One more DIY just for the fun of it :D

Since I was changing both the front and rear sprocket I started with the rear and kept the wheel loose to get enough chain slack for the front sprocket. Changing the rear sprocket will require stands of some sort to drop the rear wheel out, just changing the front sprocket could be done without stands.


Start by removing the cotter pin and loosening the axle nut on the rear wheel.
http://img523.imageshack.us/img523/6712/imgp0239of9.jpg
I then loosened the adjusting nuts and pushed the wheel forward as far as it would go. Then to drop the wheel all you have to do is pull out the rear axle and then remove the chain. After the wheel is out it's a good idea to make sure that no one messes with your rear brake, getting the pads to spread out can be a pain.

After taking the wheel out I placed it on some 4x4's to keep the brake disc from touching the ground.
http://img523.imageshack.us/img523/112/imgp0242yi9.jpg

At this point you need to unscrew the six nuts to take the sprocket off. I ended up having to kneel on the 4x4's with the wheel between my knees and putting pressure down on the center of the wheel to keep it from sliding while trying loosen these nuts. I was fairly surprised by how tight those nuts were on there.
Now you have the wheel with no sprocket
http://img521.imageshack.us/img521/4110/imgp0244cu9.jpg

Now just place the new sprocket on and tighten up the nuts. I tightened mine in sets of 2 going to opposite sides of the wheel to avoid warping anything by over tightening one side. I tightened the nuts according to the service manual at 44 ft-lbs each.
http://img355.imageshack.us/img355/9421/sequenceaz3.jpg

At this point it's time for the wheel to go back on. Since the axle is already out it's a good idea to clean and lube it. As I mentioned earlier I only put the wheel back on I didn't tighten the axle nut or adjust the chain yet since I wasn't sure how much slack would be needed for the front sprocket.

Next we'll swap out the front sprocket.

Now to change the front sprocket. To start off unscrew the bolt holding the rod to the crankcase and slip it off so that the lever hangs freely.
http://img152.imageshack.us/img152/4783/brakeky4.jpg

Next you need to unscrew the three bolts circled in red below that hold the cover. These bolts are not the same length, to help remember how they go I put them through a piece of cardboard marking which direction is up.
http://img152.imageshack.us/img152/7572/coverks2.jpg

Now you can pull the cover off and you have access to the sprocket. Before you can take the nut off the crankshaft you need to straighten out the washer that is bent over the nut.
http://img517.imageshack.us/img517/7479/imgp0256xw2.jpg

Once the washer is straight you can begin to attempt to unscrew this nut. That sucker is on there tight. With the bike in first gear and my dad holding the rear brake the wheel still kept spinning and the nut wouldn't unscrew. To stop this I took off the chain guard and placed a 2x4 over the swingarm through the tire.
http://img91.imageshack.us/img91/1088/imgp0257ya5.jpg

After that it was fairly easy to get the nut loose. It is now possible to pull the sprocket off and to place the new one on. When swapping the crank sprocket the service manual says to lubricate the new sprocket and crankshaft with molybdenum disulfide. I used some moly grease and put the sprocket on.
http://img91.imageshack.us/img91/5213/imgp0258cd7.jpg

After that I placed the washer I took off earlier back on the crankshaft and tightened the nut. To keep the wheel from spinning while tightening I used the 2x4 again but this time I placed it under the swingarm. I tightened the nut 94 ft-lbs, according to the service manual.

At this point you're pretty much done. All that's left is to put the cover and gear lever back on. Then you need to adjust your chain and tighten the rear axle.

I haven't gotten any significant saddle time with this set up and probably won't still spring time but the short test run I took had me wishing I've done this earlier and these bikes should definitely come from the factory with a 15 tooth sprocket up front.

With this set up my rpms dropped by about 1000, a little less I'd say but I was able to travel on some of the roads I've taken before pretty much a gear lower. Setting up for corners I was able to stay in the same gear and have enough power to drive through the corner. Before I was either getting close to redlining driving through corners or I'd have to grab a gear up to drive out of the corner.

EDIT: Since this DIY was published, a number of folks have come to the conclusion that the spacer side of the front sprocket should be facing in, not outwards as shown in the last picture

:clapping:

thank you, sir!

So the new sprockets you put on are 15/44. What are the stock sprockets? (I'm pretty sure it's 14 in front, but not sure on the rear)

So the new sprockets you put on are 15/44. What are the stock sprockets? (I'm pretty sure it's 14 in front, but not sure on the rear)

Stock for the '08+ is 14/45 :thumbup:

Makes sense. That is a difference in overall gearing (14/45 to 15/44) of just a little under 10%, so if it was turning 10k rpm at a certain speed before, it would now be a little over 9K rpm.

Do the numbers represent how many teeth the sprocket has?

What would be a good setup for a more fuel efficient run?

Do the numbers represent how many teeth the sprocket has?
Yes

What would be a good setup for a more fuel efficient run?
The setup that he uses in the DIY would be more fuel efficient. Any setup that has a front sprocket with more teeth than stock and a rear sprocket with less teeth than stock will offer better fuel mileage. If your bike has the power to pull then this will also give you a higher top speed (and less acceleration), so you can only change the gearing so much.
So the closer the ratio between the front and rear sprocket is 1:1 then the better mileage and top speed the bike will have. And vice versa.

Any setup that has a front sprocket with more teeth than stock and a rear sprocket with less teeth than stock will offer better fuel mileage. If your bike has the power to pull then this will also give you a higher top speed (and less acceleration), so you can only change the gearing so much.
So the closer the ratio between the front and rear sprocket is 1:1 then the better mileage and top speed the bike will have. And vice versa.

Neither of these statements are true. The only thing that is guaranteed with a sprocket swap for one with a taller gear (larger front and/or smaller rear) is that for a given road speed, engine revs will be lower.

At that same given road speed, the bike needs to produce the exact same thrust at the rear wheel (often measured as rear-wheel horsepower). If the engine is turning less revs, that often means the rider must use more throttle at that lower engine speed. Whether or not using more throttle at a lower engine speed uses more or less fuel than a higher engine speed with less throttle, well, the answer is it depends. And in many cases, there is actually very little difference at the end (for all reasonable changes in gearing). Depends on the particular engine's power curve, and fuel usage along that power curve. There's no free lunch. To push a certain bike a certain speed through the air takes a fixed amount of horsepower.

As for a taller gear ratio allowing a higher top speed, that's also B.S. for almost all production motorcycles. The only way that would be true is if the motorcycle could pull to the engine redline in top gear, so a taller gear ratio would allow the bike to go faster at the same redline. The ninjette can't pull to redline in top gear, so the point is moot. And any sportbike on the market today is geared such that it can't redline in top gear either; even the hyperbikes are hitting their 186 mph limiter at significantly below their engine's redlines.

Neither of these statements are true. The only thing that is guaranteed with a sprocket swap for one with a taller gear (larger front and/or smaller rear) is that for a given road speed, engine revs will be lower.
Then shouldn't this give better mileage? If you are traveling at a constant speed with 1K less revs then your mileage should be better in theory. I realize that if you're cruising at 5K then it's hard to go down to 4K because of the lack of power on the bike. But when you're talking the difference between 9K and 8K then the power becomes irrelevant and you can use less throttle (and so fuel) to go the same speed. Or am I missing something completely? yes, i did read your explanation in the middle, and it makes sense, but only if you're in a situation where there is a pretty big difference of power between that 1K of engine rpms
Also, for the top speed thing, I realize I should have inserted the word theoretically. A taller gear ratio theoretically gives you more top speed. Of course the ninjette can never reach redline at top speed to begin with, so it won't actually improve top speed.
I don't wish to argue, as you of course know more than I do, but if there is absolutely no gain (in any aspect) with a taller gear ratio, then why on earth would people swap sprockets? going down for the track makes sense so they can get the punch out of corners, but then why don't we all just gear down then if there's no difference in mileage?
Now I'd actually be interested if someone did a "before and after" for mileage and a sprocket swap.

I did a sprocket swap and saw zero change in mileage. The reason 99% of motorcyclists who swap sprockets do so, is for quicker acceleration. Which works. Using a shorter gear ratio allows higher revs sooner, and higher revs for just about all sportbike motors mean higher power, as they make most power not far off redline. And by going to a shorter gear ratio, many of them do lose ultimate top-speed, but gain acceleration. A great example of this would be an AMA superbike. 215+ hp at the rear wheel, but is geared to top out at 175 mph or so at most tracks, even less at some of the tighter tracks. Geared differently they'd likely reach 205 mph or more, but that wouldn't get them around the racetrack any faster. (The 2nd reason I believe sportbike riders swap out sprockets is they love to see the perceived increase in performance since their speedos are now showing faster speeds much quicker, as most bike speedos are run off the countershaft. If the dash is telling you you're accelerating faster, sure feels like you are, even if the actual performance change isn't really as drastic.)

Ninjettes are a special case. We have such a small high-revving motor already, that going to taller gearing makes the bike better behaved on the freeway. It is more comfortable for some people to be going 9.2K rpm instead of 10K pm. Or 8.3K rpm instead of 9K rpm. Less vibration, less noise, motor just feels a little better behaved. But the bike still needs to produce the same amount of hp at the rear wheel to maintain the same speed on the highway, even at those new rpm levels. And there just isn't much difference in fuel economy from 8.3k to 9k rpm, when the bike is making the same power.

If people are really interested just in better mileage, the way to manage that is riding style. A stock ninjette can range from mid-30's mpg up to high 60's mpg, with zero mechanical changes to the bike. Just a matter of how that control on the right handlebar is used.

alright, well I guess I'll just go sit this one out then...

No need to sit anything out! :) This board is for all of us to learn more about our bikes. I'm certainly not the be-all and end-all authority by any means, and I learn things from this board and others every day.

One thing that I do know though, is that motorcyclists put way too much faith in sprocket changes as some magical elixir that will give much better performance and fuel economy. When it's just math.

As Alex mentioned sprockets don't change power, this change wasn't done for more speed or less fuel. Honestly the way I ride maybe about 20% of the time I'll truly take advantage of the ninjas gas mileage.
Again as Alex said it's really all about changing the behavior of the bike, the taller gearing ratio helps me get the power I want at rpms that I feel are healthier for the engine. Rarely will I take the bike to redline anyway so not having the power to pull to redline in the taller gears isn't something that's going to bother me.

I am considering swapping the sprockets, not for fuel economy, or accelleration. Just to reduce the RPMs at highway speeds, though I will see what it is like after I have finished the mods that are in the mail (AreaP CF full system and Dynojet jet kit :D )

I find these discussions on sprocket swaps informative. I am constantly doing this on bicycles--except that on a bicycle you are dealing with a 10 sprocket cluster in the rear and a 2 or 3 chainring cluster in the front. It gets quite complicated because in the end, you are the engine. Like Alex, I plan to leave things alone. I like the quiet exhaust, so that will stay stock. I also have no complaints about the performance. I do think that the Kawa engineers did their homework--after all, you have to have done something right to be the top 250 since 1986. My only gripe with Kawa is that their factory Shop Manual leaves a lot to be desired. It very briefly describes procedures and only mentions special tools. It could, for example mention that the rear axle requires a 24mm socket. The DIYs on this forum make the manual look sick. This sprocker DIY is great for those wishing to replace worn sprockets.

Lot of opinions about sprocket teeth, power, and gear engineering. Don't need to bring out the calculus book on this one my fellow engineers. Empirical data collection works better for this. On my little Yamaha Virago 250 I dropped my rear sprocket down 4 teeth from a 45 to a 41. Not a surprise that my overall fuel economy bumped up from the original configuration (from about 80 MPG to well over 90 MPG). I commute 26 miles to the office at a max speed of about 60 MPH. It's a cruizer for gawd sake so one might expect that kind of gas mileage. Anyway. my tach tells me that I dropped around 800 - 900 RPM at that 60 MPH speed. My available acceleration dropped at the seat of my pants, and I can feel that. But at that 60 MPH cruising speed the tach is singing to me, in 800 RPM alto less. So, lets see. My RPMs dropped, my V-Twin is smoother and is happier, my fuel economy improved rather well, and I can STILL go as fast as I want. Don't need no stinkin' math to tell me that dropping the gear drive ratio from 2.81 to 2.56 was the ticket to less fuel use. My :2cents: + I will raise you 1 tooth :fightmallets:

By the way. Has anybody dropped their rear sprocket on their 2008/2009 model to 43 teeth? If so, can you feel the loss of acceleration much in any gear? :eek:

some locktight on the bolts that hold your rear sprocket on would be nice too

Hmmm.... about the sprockets..

taking what I know, if you have a matched gear ration, 1:1, that means that the rear wheel should spin at the same speed as what your engine/front sprocket is right? So for arguments sake, lets say the engines spinning at your 10k rpms, then at a 1:1 sprocket ratio, your rear wheels will be spinning at 10k rpms, which in the end means a REALLY REALLY HIGH top speed. So we can naturally assume there is zilch torque.

At the other end of the spectrum, we start separating the ratio, putting more and more teeth on the back sprocket, which means what, that for every tooth the front sprocket pulls, 1 will be pulled on the back. Which in turn means that the rear wheel does NOT spin as fast as the front sprocket. Which means... lower top speed, but a gain in torque right?

So, out of pure common sense, a closer (1:1) ratio means less torque, more top speed, and a higher (1:15) ratio means less top speed, lots more torque. In proportionality of course.

However there's the thing about saving gas..

I've got the whole idea worked in my head, but I don't know which concept I need to share first.. so bear with me please.

Power is defined as energy over time. More clearly defined here as "work" over time. Work per second you could say.

Work in a very physical sense here is basically your rpms. Each revolution of the engine/front sprocket requires a certain amount of gasoline. That gasoline gives the same amount of work every time its burned up. When you establish that, its so much more natural to make the assumption that "less rpms, is less gas, is gas saved" Thus we have the integral of the puzzle, any decrease in overall rpms needed to do anything, will save us gas.

The reason this works, is that the force you need to maintain a certain speed is yes, a certain "rear-wheel horsepower," how much of this rear-wheel horsepower is actually given by the engine is very different, and dependent on your sprocket ratio. Alex, i believe you were mistaken in assuming that rear wheel horsepower is the same as engine horsepower. If you need x amount of rear-wheel horsepower, you must ask y amount of power from the engine. But y does NOT equal x at all times. Its dependent on your sprocket set up. What happens is if you're using a 1:1 ratio, (or defined as 1/1, which is 1) you are using 100% of your y into pushing out x, giving your top physical speed from your engine. But lets say you use a 2:3, or a 1.5 sprocket ratio, then you are using 1.5 of y to push out the same amount of x, which means you have that much less maximum y to push out the same amount of x. Now, you can do this indefinitely to get more and more acceleration, but we'll run out of top speed. Where as if you went the other way and sprocket the ratio closer, you'll get more top speed. However the limiting factor is not really how much engine output there is, but rather, how fast your rear wheel can spin before it destroys itself. Wheels simply CANT spin at 14k rpm. So we take all that extra energy we can't exactly use yet, and put it into straight acceleration (with a transmission. A sprocket ratio is just a more permanent thing).

As I was writing this post, I found the best way to think about it was literally, to think about your gear box. You know the lowest gear has the most torque, the most acceleration. When you finally use up all of your horses into accelerating, you shift up, to a bigger gear, a gear with more teeth you could say.

Nope.

Pushing a bike down the road at a certain speed is always going to require the same amount of power from the engine. And the same amount of work from the engine. The rear wheel is turning at the same speed. And all of the forces trying to keep the rear wheel from turning at the same speed are exactly the same (wind resistance, rolling resistance, and every other class of friction).

The engine can certainly be turning different speeds to push the rear wheel at the same speed, that's what a transmission does, and changing the sprockets in any way will do the same thing by adjusting the effective ratio from crankshaft rotation to rear wheel rotation. But running the engine twice as fast does not use twice the fuel, and running the engine half as fast does not use half the fuel. Think about what happens when you are revving an engine with very little load on it. Notice how at 1/8th throttle, it still goes all the way to redline? Then think about when there is close to max load on it, going up a steep hill, and when you apply even full throttle, the engine in many vehicles struggles to reach redline very slowly, if it ever gets there. Amount of throttle alone does not equal amount of revs an engine produces. Amount of throttle, combined with the current load on the engine equals the amount of revs an engine produces. At a higher (taller) gear ratio (engine spinning slower), there is more load on the engine, which requires more throttle (more gas per revolution) to produce the same amount of revs. At a lower (shorter) gear ratio (engine spinning faster), there is less load on the engine, which requires less throttle to produce the same amount of revs.

All that said, the slower an engine turns to produce the same power, usually that does mean that it is using the minimum amount of fuel that it can. This is primarily due to less frictional losses in the engine at a lower engine speed, even though it needs to use somewhat more fuel per revolution to make the same amount of necessary power. Yes, bikes get better fuel mileage in 6th gear than 5th gear at a certain speed. Yes, they get better mileage in 5th gear than 4th gear, at a certain speed. But they don't get 6/5ths better mileage. And they don't get 5/4ths better mileage. Doing the math the other way: lowering the revs from 9000 to 8000 does not change the fuel consumption to 8/9ths what it was. More throttle is necessary at 8000 to make the same power that was being made at 9000 rpm. So the actual fuel consumption is a heck of a lot closer to 17/18ths what it was. Or even 35/36ths. Theoretically lower, but a small enough difference that it may not be enough to even notice. A 10% gearing change does not (and can not) result in a 10% increase in fuel efficiency, if the vehicle is driven in the exact same manner at the exact same speeds as prior.

When swapping the crank sprocket the service manual says to lubricate the new sprocket and crankshaft with molybdenum disulfide. I used some moly grease and put the sprocket on.
Thats cool that you guys use this! I dont own a motorcycle but im trying! I am however a very avid marksman. I reload my own ammunition and some of the reloads I make use Molybdenum disulfide covered bullets (I just call em moly) They yeild higher velocities, cleaner bores, and dirty fingers. :P

By the way. Has anybody dropped their rear sprocket on their 2008/2009 model to 43 teeth? If so, can you feel the loss of acceleration much in any gear? :eek:

BUMP

im also curious about this...i was actually planning on droping mine down to 41, giving me nearly the same ratio as 15/44...i know i will lose acceleration...but i feel this will be overcome by my installation of dynojet 98s and a full area p

soooo yea....anyone out there feel a very noticable loss in acceleration?

Yes, you're going to notice a difference. Even with the pipe and jet kit. If fun acceleration isn't important to you, then it'll be fine
Posted via Mobile Device

So uhh. I want a 20T front and uhh 30t rear how much extra gas is that gonna use?:D


Kidding kidding

So essentially changing out the front and rear come down to rider needs/preferences, theres a trade off either way because the same amount of energy is needed to achieve and maintain a given speed!

How does engine efficiency plays a role here?

The ability of a motor to run at higher revolutions can hinder its ability to harness energy in an efficient manner((see first attachment. m=motor)). Generally speaking about sportsbikes they are higher RPM, Higher HP to torque machines.
Demonstrated here:
http://www.sportrider.com/performance_numbers/146_motorcycle_weights_measurements/kawasaki.html

Generally speaking about the amount of bang your getting for your buck. With the absense of fuel injection and computer engine management systems and a fuel return line it's pretty easy to determine anyway you gear our little ninjette it will use the same amount of fuel.
demonstrated here:
http://upload.wikimedia.org/wikipedia/commons/a/a6/4-Stroke-Engine.gif

a 14t/45t stock setup going x mph at y RPM needs the same amount of energy as a 15T/44T going the same road speed but with a different engine speed((see second attachment.P=power V=velocity)). Another way to put it..>At the same road speed: The engine rotating more is doing a greater number of smaller burns, the engine rotating less is doing a lesser amount of burns harder. Also demonstrated above.

One critical factor left out of our pointless dispute is tire size. Demonstrated here:
http://en.wikipedia.org/wiki/Gear_ratio

And in the end to really be the fastest most fuel efficient bastard out there... wait until you get home to eat instead of showing your bike off at the local Micky Ds like I do.:D

Well hope you guys understand my point. I wasn't serious.

So uhh. I want a 20T front and uhh 30t rear how much extra gas is that gonna use?:D


Kidding kidding

So essentially changing out the front and rear come down to rider needs/preferences, theres a trade off either way because the same amount of energy is needed to achieve and maintain a given speed!

How does engine efficiency plays a role here?

The ability of a motor to run at higher revolutions can hinder its ability to harness energy in an efficient manner((see first attachment. m=motor)). Generally speaking about sportsbikes they are higher RPM, Higher HP to torque machines.
Demonstrated here:
http://www.sportrider.com/performance_numbers/146_motorcycle_weights_measurements/kawasaki.html

Generally speaking about the amount of bang your getting for your buck. With the absense of fuel injection and computer engine management systems and a fuel return line it's pretty easy to determine anyway you gear our little ninjette it will use the same amount of fuel.
demonstrated here:
http://upload.wikimedia.org/wikipedia/commons/a/a6/4-Stroke-Engine.gif

a 14t/45t stock setup going x mph at y RPM needs the same amount of energy as a 15T/44T going the same road speed but with a different engine speed((see second attachment.P=power V=velocity)). Another way to put it..>At the same road speed: The engine rotating more is doing a greater number of smaller burns, the engine rotating less is doing a lesser amount of burns harder. Also demonstrated above.

One critical factor left out of our pointless dispute is tire size. Demonstrated here:
http://en.wikipedia.org/wiki/Gear_ratio

And in the end to really be the fastest most fuel efficient bastard out there... wait until you get home to eat instead of showing your bike off at the local Micky Ds like I do.:D

Well hope you guys understand my point. I was'nt serious.

Was gona post but then decided not to Ive posted way too many times on this topic. Find my other post if your looking for some insight.

what metric size do you guys need to loosen the front sprocket?

what metric size do you guys need to loosen the front sprocket?

27mm. Search?:D

i have a 17/16 SAE size but its kinda loose

i guess i should stick with the metric sizes

:)

i guess i should stick with the metric sizes



yes, most definately. this is not a nut you want to have any "looseness" on the socket seeing as it's so tight on there.

yes, most definately. this is not a nut you want to have any "looseness" on the socket seeing as it's so tight on there.

Only a "nut" would use a non-metric socket on a Cowsooki nut:p

Only a "nut" would use a non-metric socket on a Cowsooki nut:p

Sounds nuts.
While your picking up a random 27mm socket. Grab a 17mm and a 24mm to save yourself a trip or two. 17mm right rear axle 24mm left rear.

Sounds nuts.
While your picking up a random 27mm socket. Grab a 17mm and a 24mm to save yourself a trip or two. 17mm right rear axle 24mm left rear.

HeLL!:cool: Buy a complete metric set...and get the best you can afford while U R at it. :D

after three attempts at unscrewing the sprocket nut, im still unable to take that damn nut off the sprocket.

i have a 27mm socket and a 22" drive wrench. what am i missing still? that sucker is driving me crazy. do i need to heat it up or something? melt the black rubber to loosen it? should i get a longer wrench? im running out of options already...

pleaseeeeee help.........

you need a 3 foot piece of pipe to use as a breaker bar

Flaten the bent washer, put a 2x4 through the rear rim, Get a long pipe to put over the wrench handle for extra leverage, crack it off

three foot? thats from the socket to bar end right? i got a 22" so i need more. dang!

gotta run to City mill

thanks man

three foot? thats from the socket to bar end right? i got a 22" so i need more. dang!

gotta run to City mill

thanks man

It doesnt matter as long as your getting more leverage. 2ft may even work. Longer the better. Dont go all 10 footer an sh!t :D
A good sized Dead Blow hammer might work ok aswell.

It doesnt matter as long as your getting more leverage. 2ft may even work. Longer the better. Dont go all 10 footer an sh!t :D
A good sized Dead Blow hammer might work ok aswell.

I agree. Your socket wrench can be extended with the pipe from a pipe-clamp (wood working tool) or any medium to heavy wall pipe. 2 feet will be fine if you employ the aid of a 3 pound mini-sledge hammer. Give the set-up a good whack. The longer the pipe, the better leverage. The 2x4 jammed thru the rear wheel will keep the engine from turning while you work. Don't forget to flatten the washer:eek: first. Have a torque wrench to re-install???:thumbup:

the sucker finally succumed to the mighty power of an impact wrench

took it less than 5 seconds the one ive been trying for almost 15 hrs now (cumulative)

oh well...

thanks guys

Wow..had to go impact wrench. yikes
I think I need to do what kkim does and give every nut and bolt a once over with a torque wrench. I think my front axle is way to tight.

BTW: can someone give me a link to a 15T front sprocket that doesnt need shimming? please.:)

everything i have been able to find on the subject of sprocket change everyone is doing 15 in front and either leaving the rear alone or going smaller....after going nuts trying to decide...since i really don't understand how or why with the gear ratio works...i ordered 13/47 i would like to be able to pull out into traffic faster...has anyone done this???

everything i have been able to find on the subject of sprocket change everyone is doing 15 in front and either leaving the rear alone or going smaller....after going nuts trying to decide...since i really don't understand how or why with the gear ratio works...i ordered 13/47 i would like to be able to pull out into traffic faster...has anyone done this???


That sprocket change should do the job!:thumbup:

i ordered 13/47

Check out the gearing commander (http://www.gearingcommander.com) site where you can put in the stock 2008 Ninjette, and play with the ratios to see how things will change. With a 13/47 setup, the engine will be turning 10,000 rpm in top gear at about 72 mph, and will hit redline in top gear at less than 90 mph. Most folks tend to change the gearing to something taller on the ninjette to smooth out the highway ride (by lowering revs); it's rarer to go shorter as you're suggesting (which will increase revs).

Lovely DIY, wondering if it applies to an 09 250r. Looking to do my front sprocket to a 15, not gonna touch the rear cause i dont have any stands for it.

...wondering if it applies to an 09 250r.

yes

A possible addition to pp2 of this excellent DIY:
To fully remove the shift link rod / clamp from the rod that enters the engine, you MAY have to loosen the silver hex bolt immediately to the rear of the assembly. This is the bolt that holds both the shift lever and link rod to the engine case. I had to back mine off 1 1/4 turns.

@Alex:

The gearing commander saved me from hunting for the calculator! Thanx. I just bought a 41 tooth rear ($41.99), must get stands first. Already got a torque wrench, impact driver, metric sockets (deepwell), and threadlocker (blue).

@Ninjette.org:
Any recommendations for axle lube? What about the chain? Stock OK, or do you recommend aftermarket? Mine has 1800 miles on it, have cleaned it once, lubed twice. Thanx for any help!

Johnny

@Ninjette.org:
Any recommendations for axle lube? What about the chain? Stock OK, or do you recommend aftermarket? Mine has 1800 miles on it, have cleaned it once, lubed twice.



I use Belray waterproof grease on any axle, bearings, linkages or pivot points.

stock chain is okay as long as you take care of it. at your rate, you are under maintaining your chain. check your owner's manual for cleaning/adjusting intervals.

I use wd-40 or kerosene to clean, maxima chain wax to lubricate. I've also started using dupont teflon spray as a lubricant, too.

I've actually wondered much of this about gear ratio on motorcycles and always decided that shift patterns really determine your gas mileage. Riding CVT Scooters(ranging from 25-150) you can really tell a difference in acceleration and top speed(woohoo 50mph;(] when changing variators, roller weights, and springs. But being a CVT bike I've never really been able to control my shift pattern.

I've also thought about what a street bike would be like with a CVT setup.... just googled and obviously its been a few years since I've thought of this so here are actually some CVT motorcycles, an aprilla, a honda, a ridley(some company in Oklahoma?) and Dutch E.V.A.(actually a pretty interesting bike)

At any rate gas mileage can be simplified by how much gas you burn in a given time(which for most is in correspondence to a distance). You don't generally refer to a trip somewhere in how long it will take when talking about gas usage.

btw, I know this thread is old(playing catchup), I'm new however and just thought I'd give a mention of what I didn't see people mention.

If you are going to ride a distance of 10miles and you plan on riding this distance @ 60mph.
For Instance A. You give it full throttle asap you will burn a decent amount of gas. Obviously because you are displacing a lot of gas from your gas tank out to your muffler in trade for that nice boost of speed. This is where time comes into play, you were sitting @ 0mph and it will literally take you seconds to reach 60mph. Thereafter you will cruise the rest of your ten mile trip(assuming no stops) in a decent time.
For Instance B. You are lenient on the throttle and accelerate slower than normal taking your time to reach 60mph. Obviously going slower you will travel a much longer distance for more for a longer period of time before achieving sweet 60. This ends up meaning your overall trip time will be longer all the while traveling the same length.

All in all it seems equal to me, not really to comparable either, I tested this with my 08 mustang. POS never got great gas mileage for obvious reasons, however, it did give a readout as far as mpg that were being achieved which was entirely accurate. By calculation of odometer reading and current gas tank fill at time car was started it would deviate a rather disgusting number at times. As a side note I did find out you could cheat and fill the tank up while it was still running(obviously not safe , but it only happened twice to confirm the readings). At any rate, I put 30k miles in the first year and mostly city with moderate traffic so I felt the burn. I tested out gas mileage by resetting the meter at rest and accelerating at tire squelching force and maintaining 45mph and counting the next green light as a marker. At first within the window of acceleration I "blipped" by using 8-12mpg(such a waste) for about 4 seconds and finished the distance in a rather timely manner. This worked well as I drove back and forth across town through many of the same intersections just for the sake of testing, right? I then would reset the counter and tested gas mileage with granny acceleration of 0-45 which was in the range of about 40seconds. Obviously I got my 20mpg out of it but it took me nearly a minute of gas burning to get a fraction of the distance. Maybe you can say you saved some gas in the comparing how much was used in acceleration, however when it came to distance/time I was burning a comparable amount of gas. I'd also imagine this would be equivalent to a motorcycle.

So I guess this run on rant on a dead thread has gone on much to long, then again what else better am I doing at work?... P.S. Kudos:thumbup: to you if you are reading this.

Hey, where did you buy your sprockets at? This was a good DIY thread!

Hey, where did you buy your sprockets at? This was a good DIY thread!

I've seen a decent range of sprockets on http://cheapcycleparts.com

Cool! Thanks!

thinking of going 15T front. does anyone know if the stock chain will fit ok, or is it necessary to get a new one?

thinking of going 15T front. does anyone know if the stock chain will fit ok, or is it necessary to get a new one?

Just did the swap yesterday on the wife's '09. The 15T fits perfectly and there is more than enough chain to go around (ended up on the second adjustment "notch" from the front on the swingarm). I installed an AFAM 24502-15 sprocket and it needed no shimming for proper alignment.

Just make sure you have a 27mm impact socket and a stout 1/2" drive impact wrench.

We went out riding last evening and she gave me a big :thumbup: on the switch. I've not ridden it yet, but I did with the stock gearing and I thought it was just stupid under-geared. Granted, it's a polar opposite to my Buell, but first gear on the Ninja was like the granny gear on old Ford pickup.

Chris

Thanks for the report, Chris.

May I ask, where you purchased the sprocket? possible link perhaps?

Thanks for the report, Chris.

May I ask, where you purchased the sprocket? possible link perhaps?

Sure, I'll look it up and post it.

[EDIT]: Here's the link: Drive Systems USA (http://www.drivesystemsusa.com/p/740553/afam-520-chromoly-steel-front-sprocket---kawasaki.html)

Took her bike out for a spin on Saturday. I must agree with her wholeheartedly - :thumbup::thumbup: !!!!

IMHO, it's where the bike should have been geared from the factory. It's a street bike, not a trials bike. It settles into a groove right about 60mph and ~7700rpm and it feels "happy". Acceleration isn't quite as snappy, but overall I think it's a wash because you don't have to shift like a trucker with a 13 speed Road Ranger who's in 6th by the end of the intersection.

I think the swap makes the bike a lot more friendly for the "average" rider looking for a more relaxed, longer distance bike. I don't think I would want to ride it on the expressway for hours on end at 75mph, the seat is too hard for my bum, but the bike would certainly handle it. I can't help from getting a big grin every time I ride it - it's amazing how well it handles for such a basic bike. I can't come up with a good enough excuse to buy one and also keep my Buell, unfortunately.

Chris

27mm. Search?:D

Then 1-1/16 should also work fine if you have one lying around. There is one-half of one-thousandth of an inch difference between 27mm and 1 1/16 inch. 1.0625 inch = 1 1/16 inch 1.063 inch = 27mm

BTW: can someone give me a link to a 15T front sprocket that doesnt need shimming? please.:)

The Drivenracing.com sprocket 1098-520-15T measures the correct 9.3mm if anyone is searching for the new gen one.

I did the swap but could never get the nut to budge with a breaker bar. I had to resort to an electric impact wrench (2x4 through the wheel not required) on the sprocket nut and the rear axle nut to adjust the chain.

An impact wrench removes these buggers in about 3 seconds.

http://www.ridegear.com/detail.cfm?model_ID=0&Category_ID=26&manufacturer_ID=730&product_ID=44432&related=long

Random link, the picture is not correct, but this is what it looks like.

Howday All:

I had the 41 tooth rear sprocket installed along with a 2 Bros Racing slip on (kinda tired of people not hearing me and merging with traffic). The 41 tooth has been so far remarkable. Stock, the bike would turn about 5000rpm @ 45mph in 6th gear, now it goes about 50mph (indicated) in 6th at 5k rpm. Highway speeds (65+) are more relaxed, even with the bark from the new lungs!

Johnny

An air wrench with an impact socket makes the take off a real breeze.:thumbup:

Good write up. Some additional information should be added in the original post like needing a 27mm socket to remove the front sprocket, etc.

QUESTION:
I removed my OEM 14 tooth sprocket and will be replacing it with JTS 15 tooth sprocket a noticed it has a rubber washer on each side. Do I need remove these and place them on the new sprocket?

JTF515.15
PN: 80-985-15

EDIT:
Don't need the rubber and for sprocket (JTF515.15). I need to add shim (spacer) http://www.ninjette.org/forums/showpost.php?p=255716&postcount=42

Thanks everyone.

Common sense suggests that a taller gear will make the bike go faster. As it was brought up by Alex, I believe...it doesnt work that way on these ninjettes.
I went to a 16/41 and finally had the chance to run as fast as i could over some distance, maybe 3-4 miles giving plenty of time for the bike to do its best.
Indicated speed in 5th was 100+ and it got right up to speed.
Indicated speed in 6th was 100+ and it took maybe a minute to get there.
In both...I had a strong head wind.
But the good news is that I can run at 80+ and the engine just sits above 8k.
At this point, got 119 mi out of 2.3 gallons running at 70-80 all the way.
Soooo pleased with this simple mod.

Common sense suggests that a taller gear will make the bike go faster. As it was brought up by Alex, I believe...it doesnt work that way on these ninjettes.
I went to a 16/41 and finally had the chance to run as fast as i could over some distance, maybe 3-4 miles giving plenty of time for the bike to do its best.
Indicated speed in 5th was 100+ and it got right up to speed.
Indicated speed in 6th was 100+ and it took maybe a minute to get there.
In both...I had a strong head wind.
But the good news is that I can run at 80+ and the engine just sits above 8k.
At this point, got 119 mi out of 2.3 gallons running at 70-80 all the way.
Soooo pleased with this simple mod.

You have to mod the bike for more horsepower to get the benefit of more speed with the taller gear. Increase the power and tourque and the motors ability to turn the taller gear and presto faster bike. In my opinion you went too far 16/41 is way too tall for the best speed with bolt-ons. (great for mileage no doubt) I tested a number of sprockets on the dragstrip. Got the best results with a 14/41. Weight plays a factor. Im a lightweight under 150 geared up. Over 150lbs my best guess would be 15/45 or 14/42 over 175lbs 14/43 over 200lbs leave it stock.

I posted it becasue it's a pretty good illustration of what Alex brought up...top speed is based on the work it takes to move a bike and not the way you gear it. Yes, you're right...the gears are a little tall for street work but...ya gotta understand....I have to travel miles and miles to get to the playground...even a little 200 mile saturday spends maybe 150 miles on parkways. Jetting and stuff is more than this noob mechanic wants to attempt. At this point...anything more complicated than turning a wrench and getting the screw to go back into the hole it came from is beyond me.

When I ordered the larger counter shaft sprocket I also ordered a new lock washer for the nut. Since my sprocket choice needed to be shimmed I simply put the old lock washer on the drive shaft on the other side of the sprocket and used it for the spacer/shim.:thumbup:

I posted it becasue it's a pretty good illustration of what Alex brought up...top speed is based on the work it takes to move a bike and not the way you gear it. Yes, you're right...the gears are a little tall for street work but...ya gotta understand....I have to travel miles and miles to get to the playground...even a little 200 mile saturday spends maybe 150 miles on parkways. Jetting and stuff is more than this noob mechanic wants to attempt. At this point...anything more complicated than turning a wrench and getting the screw to go back into the hole it came from is beyond me.

I hear ya.
Your good for mileage with your set up. No doubt. DONT be afraid to jet the bike. Follow the step by step instuctions in the DIY its a breeze. Check out the jetting database Its full of info on the proper jets for your area, altitude etc. That is if your willing of course. OTHERWISE enjoy your MPG gains. God knows your gona need them with these gas prices.
Besides if you want to go fast you can always strap on your FZ-6.

great source for sprockets and chains:

www.sprocketcenter.com

or

www.rockymountainatvmc.com

also, both sites offer free shipping for orders over $100

I just got my Driven sprocket from Fatbikez.com. http://fatbikez.com/driven-kawasaki-ninja-250r-2008-2009-front-sprocket-520-chain.html for $22.99 shipped after the "ship4free" coupon code. The Driven sprocket is advertised as lighter than the oem one. I need to weigh the oem one when I remove it. I weighed the driven sprocket on our shipping scale and it came up at 6 oz. Too bad our scale isn't accurate to a decimal point in ounces.

Well, I got my Driven sprocket on last night. It took a 4' cheater bar and a 2x4. When I heard a loud crack, I thought my 2x4 had just snapped. My impact gun didn't do anything to it. It was crazy tight.

I got a chance to weigh the oem one with the rubber still attached to it. On the same scale as the one I used before, it actually comes up slightly lighter than the Driven sprocket. Maybe I was wrong and they advertised it to be light weight, but not compared to the oem sprocket. Maybe compared to the other aftermarket sprockets? The oem sprocket with rubber weighed in at 6 oz, just like the Driven one, but when I switched to lbs, it read .3 whereas the Driven read .4. I let it sit there to see if the weight would change, but it didn't. I wonder how heavy the JT one is? As far as weight is concerned, I'm glad the Driven one is comparable to the stock one.

One question though, was it ok for me to not reinstall the rubber pieces onto the new sprocket? It seems like they're designed to be dampeners.

Finally got my rear 43T Superlite Black 520 Driven sprocket in. I put it on the same scale I used for the 15T front and it reads 1.5 lbs. When I get the oem rear sprocket off, I'll weight that as well.

I put a 15T on last year and like it, the rear is the stock sprocket.

How small can I go on a rear sprocket using the stock chain and the 15T front?

Thanks.

I just put on a 43T with my 15T front and it dropped the RPM's by a lot on the freeway. So much so that I now have to down shift if I need to pass someone. I kinda like it. I believe people have gone down to a 41 before.

I put a 15T on last year and like it, the rear is the stock sprocket.

How small can I go on a rear sprocket using the stock chain and the 15T front?

Thanks.

I run 15/42 on stock chain, no problem. Can't comment on smaller.

Just to update, the stock sprocket weighed 2.2lbs on my scale. That's 0.7 lbs heavier than the Driven sprocket I installed. Nice amount of weight savings in rotational mass and it's still steel.

I got around to putting on a 43T Renthal rear sprocket 210U-520-43P-HA after sorting out the strangled flat spot in the carbs, thanks to Kelly and others. I had put a 15T front on last fall, but the poor running down low made taller gearing seem not the way to go until that was solved.

Now that the bike is running flawlessly, probably like it *should* have come from the factory, the 43T rear went on today and the taller gearing makes the little Ninja start to feel like larger (more normal) bike gearing to me. I probably could even have gone to a 41T and been even happier, but this it for a while it for a while.

Pulling the rear nuts, axle, and countershaft nut is a really good excuse to buy a cheap HF electric impact wrench and reduces coaxing nuts to a 2 second battle.

Thanks to everyone for the info on the forum.:thumbup:

Count me as a happy 15t front-sprocket convert. I was replacing & shimming my cush drive, and took the opportunity to try the 15t front sprocket.

I purchased the JTF1539.15 I found from a seller on Amazon.

I could not get the factory-torqued sprocket nut to budge with the tools I had, and darned near snapped a piece of wood I had placed through the rear rim.

I wheeled the bike 2 houses over to my neighbor's and used his air impact wrench. A few seconds later the nut was off, and I didn't hurt myself nor the bike. :thumbup: I fussed a bit getting the chain remounted, but I'm sure there's a knack to doing it that I hadn't learned.

I'm 200+ lbs with gear on, have 150/60/17 & 120/70/17 BT-016's mounted, and I'd say the gearing & ride quality is just about dead-on for me and areas where I ride.

In 6th gear, I see an indicated 10mph per 1000 RPM on the tach, like others. 60 MPH is a sweet and smooth purr at 6000 RPM.

Thanks you all that take to the time to write-up these great DIY's and share what they've learned.

LOVE the 15/41 set up and I weigh 215 lbs. Can't wait to put a 130 tire on the back . Mileage update later.:thumbup:

Bought my second JTF1539.15 but not sure how I'm going to install it. :( I simply don't have the tools.

Ok I just changed my set up on a 2008' from a stock 14/45 to a 13/45 all aluminum instead of stock steel. I adjusted the fuel mixture to were the bike idles at 1600 rpm now fully warmed up. Its the best mod I've done. My friend has the same bike and is having lots of trouble keeping up with me from 0 to 80 mph. My bike beats his now in every aspect when riding, and im not show boating its true. No loss of top speed, stronger low and mid range, smoother and the power band seems to carry all the way to read line. Shifts are a little quick but that's because your getting to mph quicker. Without the fuel mixture adjustment this is not a good mod. Again this was my best mod ever! Throw in upgraded headers, muffler, k&n atv air filters with no air box, and #30 dino jet kit and you got yourself a screaming 250r with wings. Oh did I mention I know nothing about gear ratios ;+)

Just wanted to mention that I think the picture has the front sprocket facing the wrong way. The JT label and Lip should be facing the engine. Confused me for a while.

Ok I just changed my set up on a 2008' from a stock 14/45 to a 13/45 all aluminum instead of stock steel. I adjusted the fuel mixture to were the bike idles at 1600 rpm now fully warmed up. Its the best mod I've done. My friend has the same bike and is having lots of trouble keeping up with me from 0 to 80 mph. My bike beats his now in every aspect when riding, and im not show boating its true. No loss of top speed, stronger low and mid range, smoother and the power band seems to carry all the way to read line. Shifts are a little quick but that's because your getting to mph quicker. Without the fuel mixture adjustment this is not a good mod. Again this was my best mod ever! Throw in upgraded headers, muffler, k&n atv air filters with no air box, and #30 dino jet kit and you got yourself a screaming 250r with wings. Oh did I mention I know nothing about gear ratios ;+)

Glad you like your mod. Sounds like it's fun and your having fun playing with your bike. Be safe out there. Don't be a squid :D

after three attempts at unscrewing the sprocket nut, im still unable to take that damn nut off the sprocket.

i have a 27mm socket and a 22" drive wrench. what am i missing still? that sucker is driving me crazy. do i need to heat it up or something? melt the black rubber to loosen it? should i get a longer wrench? im running out of options already...

pleaseeeeee help.........dont heat...use a pipe and extend the wrench. sometimes just making the wrench longer with a pipe works on the toughness nut

Feck me. Now I have to take it all apart and flip my sprocket. I am pretty surprised that DIY was wrong for 3 years.

dont heat...use a pipe and extend the wrench. sometimes just making the wrench longer with a pipe works on the toughness nut

Be careful. I dented my tank with the breaker bar when the nut finally broke loose.

Just wanted to mention that I think the picture has the front sprocket facing the wrong way. The JT label and Lip should be facing the engine. Confused me for a while.

and also interesting;y, that front sprocket in the original post is for the pre-gen. Pre-gen is JTF-516, the new gen is JTF-1539. The Pre-gen front sprocket in theory should fit the current gen bike, but definitely NOT VICE VERSA.

How much am I supposed to pay if I let a dealer do this for me (ballpark figure) for the front sprocket change?

Shouldn't take an experienced motorcycle mechanic more than an hour, two at the maximum, including them loosening and re-aligning your rear tire, checking chain slack afterward. Assume hourly rate of ~$70-80/hr, so I'd say $160 MAX.

I found out this can be done without taking off the chain, if you're stubborn about it and very careful.

That said, I had a HELL of a time breaking that nut loose to replace my 15T once the teeth started to hook after some 17,000mi. Duckman, I honestly don't know how you did that. I had a 6' breaker bar going, putting all of my ~150lbs on the rear brake pedal and it still wouldn't budge. Even tried a penetrating lubricant and some modest heat as options. Instead, the chain would (essentially) stretch and allow me to rotate the countersprocket around with the nut through ~80 degrees of rotation. I finally resorted to just putting a 2x4 thru the rear wheel and doing it that way.

Lettering goes in or out? My 15 tooth sprocket just showed up today. Some people say Lettering/spacer thing in, some say out. I see you put yours out.

Edit never mind, actually did some reading. Lettering in.

and also interesting;y, that front sprocket in the original post is for the pre-gen. Pre-gen is JTF-516, the new gen is JTF-1539. The Pre-gen front sprocket in theory should fit the current gen bike, but definitely NOT VICE VERSA.

I just received mine today from bike bandit it was a jtf516-15

http://www.bikebandit.com/jt-sprockets-steel-sprocket?mg=62158&t=1&td=1 second one down. Is this wrong, I know it will work but is there a new gen one?

I installed my sprocket upgrade this past weekend. I made a huge a mistake by removing the chain before the front sprocket.

I thought I had to buy a whole new master link and reattach the chain but eventually got it off w/smarts. Hard to describe but I did manage to take a pic of how I did it. I'll post up later tonight.

2010 Ninja I Recieved jtf516-15. Do I need to shim this out or will I be ok. All the previous Threads I didnt see anything about shimming till yesterday.

2010 Ninja I Recieved jtf516-15. Do I need to shim this out or will I be ok. All the previous Threads I didnt see anything about shimming till yesterday.

I had one of the JTF516-15 on my '08 for ~17,000mi, before it needed replacing. No shim was used. That said, if you can afford to wait to get a shim, I would. It's a small difference, but if my original 15T had been shimmed, I suspect it (and my chain) would've lasted longer.

When I replaced my sprocket with the old style thinner sprocket, I had also ordered a new lock washer. I placed the old lock washer on the shaft first on the engine side of the cover, then the sprocket, then the new lock washer. If you read the earlier listings you will also find a spacer part number you can order that is used in the transmission. I have a 15/42 installed in one bike and 16/42 in the other. If you use a 16 tooth front sprocket you have to grind some metal out of your chain cover so the chain does not rub. If I were going to do it again I would use a 15/39 or 15/40 to avoid having to dremel out the sprocket cover. The 16/42 allows me to travel at 77 MPH at 8000 RPM instead of 60 MPH at 8000 RPM.:thumbup:

A word of warning: I damaged my output shaft, and/or bearings, by removing the stubborn counter-sprocket nut. My method of removal was no different than is mentioned in this thread. I continued to ride for another 20K miles, so it wasn't critical, but every now and again, when the road was super smooth, I could just feel a bit of unbalance. This was just a suspicion, until I went to replace my clutch, and damaged the input shaft, and/or bearings, removing/installing the nut for the clutch basket. I had the same damage, but it was more severe, and more obvious this time.

It is my belief that using breaker bars, and torque wrenches on these nuts is a potential cause of damage. For now on, I will only use an impact-wrench for these types of applications. You may not get the perfect torque speck, but getting it snug with the impact wrench should get it close, without the added risk of damage. I did this with a new engine, and have had no problems.... I forgot what it felt like to ride with a smooth transmission.

lol good topic here lol. I am sure i will put a 15t front. just to help with highway rpms

lol good topic here lol. I am sure i will put a 15t front. just to help with highway rpms

Like others have said, it does a lot more than that... it runs smoother on city streets too. :)

I am amazed at what one tooth can do!

A word of warning: I damaged my output shaft, and/or bearings, by removing the stubborn counter-sprocket nut. My method of removal was no different than is mentioned in this thread. I continued to ride for another 20K miles, so it wasn't critical, but every now and again, when the road was super smooth, I could just feel a bit of unbalance. This was just a suspicion, until I went to replace my clutch, and damaged the input shaft, and/or bearings, removing/installing the nut for the clutch basket. I had the same damage, but it was more severe, and more obvious this time.

It is my belief that using breaker bars, and torque wrenches on these nuts is a potential cause of damage. For now on, I will only use an impact-wrench for these types of applications. You may not get the perfect torque speck, but getting it snug with the impact wrench should get it close, without the added risk of damage. I did this with a new engine, and have had no problems.... I forgot what it felt like to ride with a smooth transmission.

How did you fix it?

How did you fix it?

Long story short..... a new engine. If you read the thread where I lament about ruining my reputation here, it gives the whole story. It was a rough year.

I still have the old engine on my floor, and MAY have it rebuilt, but don't know if it would be cost effective it flip or not. I never did modify the registration with the new engine VIN#..... hope that doesn't come back to bite me.

Long story short..... a new engine. If you read the thread where I lament about ruining my reputation here, it gives the whole story. It was a rough year.

I still have the old engine on my floor, and MAY have it rebuilt, but don't know if it would be cost effective it flip or not. I never did modify the registration with the new engine VIN#..... hope that doesn't come back to bite me.

Ah. I thought that was because of a noise that persisted after the engine swap. Better luck to you going forward!

Ah. I thought that was because of a noise that persisted after the engine swap. Better luck to you going forward!

No, the new engine is good. The noise you are referring to either went away, or bothers me a lot less now. I'm a bit less compulsive these days (still trying to nail down the jetting though.... getting close).

Got another JTF 1539.15 and JTR 486.41 today. Not sure I should attempt the front sprocket install after seeing headshrink's problems. :/

When I replaced my sprocket with the old style thinner sprocket, I had also ordered a new lock washer. I placed the old lock washer on the shaft first on the engine side of the cover, then the sprocket, then the new lock washer. If you read the earlier listings you will also find a spacer part number you can order that is used in the transmission. I have a 15/42 installed in one bike and 16/42 in the other. If you use a 16 tooth front sprocket you have to grind some metal out of your chain cover so the chain does not rub. If I were going to do it again I would use a 15/39 or 15/40 to avoid having to dremel out the sprocket cover. The 16/42 allows me to travel at 77 MPH at 8000 RPM instead of 60 MPH at 8000 RPM.:thumbup:
I can't recall if I've got a 38 or 39 tooth rear but I'm taking it off and it's only got a couple thousand miles on it (basically threw it on, crossed the country, and stopped). It's pretty small and we had to remove a link in the chain even with the 15T front. ninja250's/Casey's chain-maker/breaker really helped with the OEM chain. :) Now I've got to use the Harbor Freight chain breaker tool to remove extra links and rivet my 110-link replacement (Youtube has a guide for using it to rivet). I guess what I'm trying to say is: It's yours, if you want it.

Got another JTF 1539.15 and JTR 486.41 today. Not sure I should attempt the front sprocket install after seeing headshrink's problems. :/


I assume you're referring to the possible bent shaft or damaged bearings... It was a pretty subtle thing on the counter-sprocket side of my original engine, and was never even verified. It was the clutch side that put me over the edge to replace the engine. I haven't had any problems sense then. This is partly due to the entire big-picture experience teaching me not to be so compulsive about motorcycle maintainance.... In fact, I can now proudly say that I rode to/from work today, in the rain, with a bald rear tire :thumbup: Ok, so the replacement comes with this next weeks paycheck, but before I would have replaced it at the slightest hint that a single wear-bar was exposed.

I put the 15T on my replacement engine as well, and have not had any issues with it. However, I used an impact wrench instead of a breaker bar on the CS nut. IMO, specific torque on this nut is not critical because of the splined washer that is bent to hold the nut from spinning.

Ah. Well, I don't have an impact wrench and I am willing to try it with what I have.

Now, I think I might have made a mistake. In anticipation of my new chain and sprockets arriving in the mail, I went ahead and broke off my old chain, loosened the nuts on the rear sprocket, and removed the front sprocket cover. Now that the new chain and sprockets are here, I realize that I can't use a completely disconnected rear tire to hold a CS sprocket from turning as I try to loosen the nut. :(

I feel like it may be a bad idea to install the new chain with the new rear sprocket with the old front sprocket just to put all that force into it, especially when I still have the same front sprocket on there that a horribly failed chain was used with (cracked, missing, and C-shaped roller links visibly chewed up my last rear sprocket; had to have done something to the front too though it looked much better).

I don't see how else to do it though, so I will be attempting to install the rear sprocket and new chain today unless someone has a better idea. Wish me luck!

Ah. Well, I don't have an impact wrench and I am willing to try it with what I have.

Now, I think I might have made a mistake. In anticipation of my new chain and sprockets arriving in the mail, I went ahead and broke off my old chain, loosened the nuts on the rear sprocket, and removed the front sprocket cover. Now that the new chain and sprockets are here, I realize that I can't use a completely disconnected rear tire to hold a CS sprocket from turning as I try to loosen the nut. :(

I feel like it may be a bad idea to install the new chain with the new rear sprocket with the old front sprocket just to put all that force into it, especially when I still have the same front sprocket on there that a horribly failed chain was used with (cracked, missing, and C-shaped roller links visibly chewed up my last rear sprocket; had to have done something to the front too though it looked much better).

I don't see how else to do it though, so I will be attempting to install the rear sprocket and new chain today unless someone has a better idea. Wish me luck!

Use the old chain. Take a spare piece of wire and hook the ends together on the slack side.

Now, I think I might have made a mistake. In anticipation of my new chain and sprockets arriving in the mail, I went ahead and broke off my old chain, loosened the nuts on the rear sprocket, and removed the front sprocket cover. Now that the new chain and sprockets are here, I realize that I can't use a completely disconnected rear tire to hold a CS sprocket from turning as I try to loosen the nut. :(

put the chain back on. wire it to the other end of the chain quick so it holds on the sprocket. re-intall the wheel. put a piece of wood through the spokes so it jams on the swingarm. CS sprocket nut will come right loose.

My buddy and I did that method on his CBR600 without issue.

Use the old chain. Take a spare piece of wire and hook the ends together on the slack side.

put the chain back on. wire it to the other end of the chain quick so it holds on the sprocket. re-intall the wheel. put a piece of wood through the spokes so it jams on the swingarm. CS sprocket nut will come right loose.

My buddy and I did that method on his CBR600 without issue.

Good idea. I would have tried it but my mother already took it for scrap metal even though I told her that steel was worthless. I'm already trying to get it back. Hope she didn't already scrap it.

hahaha I bet they won't take it. It's got rubber o-rings in there :lol:

OK, all this talk about the sprocket nut, so it's time for something that goes hand-in-hand: Impact Wrenches.

I don't have an air compressor or an outlet by the bike. Unlike when I was in an apartment, I am finally in a living situation where I can run an extension cord, but I still think something I can power off of the motorcycle battery in a pinch would be best.

Anyone think this will do the job on that countershaft sprocket?
http://www.ninjette.org/forums/attachment.php?attachmentid=17539&stc=1&d=1331872842
http://www.northerntool.com/shop/tools/product_200479025_200479025

Delivers 280 ft.-lbs. of max. torque
12V, 80 Watt motor
Plugs into 12V DC power outlet
2500–5500 RPM no-load speed range
Reversible
1/2in. detent pin anvil
11ft. power cord
Comes with 2 double-end sockets: 11/16in. x 3/4in., 13/16in. x 7/8in.
Includes two 10A fuses and carry case

Well, I wish I had bought that one. Instead, I bought the last one on clearance at Harbor Freight ($20 after coupon). So how about this?
http://www.ninjette.org/forums/attachment.php?attachmentid=17540&stc=1&d=1331873346
http://www.harborfreight.com/12-volt-1-2-half-inch-emergency-impact-wrench-92349.html

Get back on the road in minutes with this portable 12v impact wrench. This impact wrench delivers up to 150 ft. lbs. of torque to power off lug nuts.

11 ft. cord with cigarette lighter plug
Reversible--removes and installs lug nuts
Includes 11/16'', 3/4'', 13/16'', 7/8'' chrome steel sockets

1/2'' square drive
30-40 blows per minute
Shipping Weight: 5.75 lbs.

It's only 150 ft-lbs instead of 280. I read about people having problems with simple over-tightened lugnuts, and I'd imagine that a CS sprocket is going to be tougher. I sure hope this works.

hahaha I bet they won't take it. It's got rubber o-rings in there :lol:

I told her that too but she wouldn't listen! She can have my steel sprockets if no one wants my low-mileage 38T rear (paging Fleshbazbo). :)

I can't imagine that it wouldn't work.... it is a Kawi after all ;)

A cordless might suit your needs a little better, but that depends on how much of an issue $$ is, and if you anticipate using the tool much.

I can't imagine that it wouldn't work.... it is a Kawi after all ;)

A cordless might suit your needs a little better, but that depends on how much of an issue $$ is, and if you anticipate using the tool much.

When I google for 12v impact wrench, I see many pictures that are exactly the same but are not green and Kawi-branded, so it's just fluff. The dead give-away? SAE-only socket sizes (not metric). :)

I don't really expect to use it for much. Bar ends, sprockets, etc. That's why my budget was for $20-30. My current bar ends have already been freed and I'm not sure it's enough for my sprocket, so it still may not have been a good idea. We'll see when I try it out! :thumbup:

Anyway, I was reading the $20 HF unit's manual which gives instructions as if using it on cager lugnuts is the only use and it specifically said NOT to tighten the nuts with it. Well, then, why does it have a reverse function?! :D

Anyway, I was reading the $20 HF unit's manual which gives instructions as if using it on cager lugnuts is the only use and it specifically said NOT to tighten the nuts with it. Well, then, why does it have a reverse function?! :D

That's a good point. Technically I believe you aren't supposed to use an impact wrench in reverse anyways, but I think it can still be useful to spin a nut on, and use a torque wrench to finish it off.

Well, I got mine off when I figured out that you weren't supposed to push down on the nut with the socket using my 12v emergency impact wrench. The manual only said that it takes time to accelerate before it will hammer because it is electric, but you'd just hear it spin forever internally without knocking the nut if you didn't reduce pressure on the nut. I had to use it on the front axle nut too because I found it much too tight, once again, and I couldn't turn it by myself when using my T-handle wrench (whole axle would turn).

Alex: Can you please edit the OP's DIY, post and PDF, with a word of warning about the correct CS sprocket orientation? It only makes sense for the spacer side to go IN or else the exact size difference between the pregen and newgen wouldn't matter, but this wasn't obvious to the OP or others following this DIY. Vampyre, for example:
Feck me. Now I have to take it all apart and flip my sprocket. I am pretty surprised that DIY was wrong for 3 years.

It was mentioned sometime that first year, but it is a long thread and most probably don't read it all (don't blame them).

It was mentioned sometime that first year, but it is a long thread and most probably don't read it all (don't blame them).

Yeah, but the DIYs get PDF'd and that info doesn't go with it. :(

Not to mention, the copy/paste thieves using the info on other sites/unsuspecting users.

Is that edit correct at this point?

Yeah, but the DIYs get PDF'd and that info doesn't go with it. :(

Not to mention, the copy/paste thieves using the info on other sites/unsuspecting users.

Very good point, I didn't consider the PDF. It's a good idea anyways because if the DIY is self-explanatory, many (including myself) often don't keep reading because it usually isn't needed. So yes, an edit in the OP is only prudent. I wasn't disagreeing with you, maybe just splitting hairs for the sake of conversation... it's lonely here at night ;)

Is it true that if i got a bigger rear sproket and smaller front that it would put my spedo out?

No, not on our ninjettes. The speedometer is driven off of the front wheel, so any gearing changes have no effect. This is rare, as in most bikes the speedometer is driven off of the transmission output shaft, so any gearing changes do have an effect.

EDIT: Oops... Alex got there first. ;)

Ohh thats intresting to know thought i was gunna have problems if i was to change the sproket, next question how much would putting a 47t as the rear affect teh top end speed?

Haha thanks for the replys though :D

www.gearingcommander.com

Ohh thats intresting to know thought i was gunna have problems if i was to change the sproket, next question how much would putting a 47t as the rear affect teh top end speed?

Haha thanks for the replys though :D

Not really much you can do to change the top end speed (except lower it of course). The ninja is power limited, so you will run out of motor before you run out of gear.

With the 47 rear you may be able to get to the red-line in 6th gear.

Not really much you can do to change the top end speed (except lower it of course). The ninja is power limited, so you will run out of motor before you run out of gear.

With the 47 rear you may be able to get to the red-line in 6th gear.

ohh thats cool with faster acceleration right?

Is that edit correct at this point?

Looks good to me. Thanks, Alex!

Edit: I see we lost our PDF though. Just waiting on confirmation?

ohh thats cool with faster acceleration right?

yes. I like my 14/47 setup. :thumbup: just a little quicker to redline, nothing insanely 600cc-esque.

makes me :)

ohh thats cool with faster acceleration right?

Yes. The downside is you will be ~11k rpm at 75mph. Pay particular attention to your oil consumption.

Faster acceleration also means quicker shifting.

I ride the highway quite often, so I prefer the 15/45 setup.

more like 10,000 http://faq.ninja250.org/speed/#noredir

solution. Ride back roads.
another solution. Ride at 70 instead of 75. That's 9500 rpm

Yes. The downside is you will be ~11k rpm at 75mph. Pay particular attention to your oil consumption.

Faster acceleration also means quicker shifting.

I ride the highway quite often, so I prefer the 15/45 setup.

Woahh is that in gear 6 as well?

Woahh is that in gear 6 as well?

Yep. Plugged your info into the gearing commander website and you will be around 10K at 75mph.

I run 8.5K at 75 with 15/45 gearing.

yes. I like my 14/47 setup. :thumbup: just a little quicker to redline, nothing insanely 600cc-esque.

makes me :)

Whats your total top speed around then? surely it cant be like 80-85mph?

Yep. Plugged your info into the gearing commander website and you will be around 10K at 75mph.

I run 8.5K at 75 with 15/45 gearing.

ohh okay thanks for that i must have read it wrong. is it me or is that really bad top speed to loose possibly 20mph? sorry not good with the mechanical so i could just be going off on one :rolleyes:

ohh okay thanks for that i must have read it wrong. is it me or is that really bad top speed to loose possibly 20mph? sorry not good with the mechanical so i could just be going off on one :rolleyes:

If you weren't power limited then yes you would loose 20mph. But since the ninja doesn't have enough power to get to redline normally you are not loosing any on the top.

In actuality, you might have a slightly higher top speed than stock gearing. I find with 15/45 gearing I can go faster in 5th than I can in 6th.

If you weren't power limited then yes you would loose 20mph. But since the ninja doesn't have enough power to get to redline normally you are not loosing any on the top.

In actuality, you might have a slightly higher top speed than stock gearing. I find with 15/45 gearing I can go faster in 5th than I can in 6th.

riiight im getting this now lol, i think before i do this sprocket change i'll see what the top is, i've had 100mph out of her with everything stock but havnt tried to go above that because i know i'll end up getting bored if i know its limits, dont ask why its just how i am haha then i'll be able to compare thanks for all the help though good to know that i wont feel loosing the power to bad sorry for the thread jack as well :thumbup:

Whats your total top speed around then? surely it cant be like 80-85mph?


Dunno. I don't really do top speed runs on roads. Fastest I got to was about 85 (corrected speed) on the freeway and was at about 11,000 rpm.

NOTE: I have 100/90-16 F, 130/90-16 rear tires. If you have 100/80-16 F and 130/80-16 rear, at 85 (corrected speed) you'll be turning 11,500 rpm with 14/47 gearing.

EDIT: ^ I was assuming you had a pregen... fyi, as long as you're on stock tires, you should be pulling about 11,500 rpm at 85. I was only talking about tire heights because my tires are not oem sizes, and are going to change my numbers a little bit. :o

riiight im getting this now lol, i think before i do this sprocket change i'll see what the top is, i've had 100mph out of her with everything stock but havnt tried to go above that because i know i'll end up getting bored if i know its limits, dont ask why its just how i am haha then i'll be able to compare thanks for all the help though good to know that i wont feel loosing the power to bad sorry for the thread jack as well :thumbup:

Just think of Newtonian physics with equal and opposite reactions for every action and you'll see why it can't go appreciably faster from a gearing change without some other factor like being redline-limited.

I just swapped out my front sprocket and I noticed it has a bit of a clickity-clack when the rear tire i spinning either direction. The noise is something between the chain and the sprocket.

I also re-adjusted the chain (1 inch chain slack, rear wheel at same "tick mark"), wiped all the old grease off with a rag, and lubed it with some of this Dupont stuff: http://www.amazon.com/gp/product/B003OBP63S/ref=oh_details_o03_s00_i00

Anybody know how to fix this?

I just swapped out my front sprocket and I noticed it has a bit of a clickity-clack when the rear tire i spinning either direction. The noise is something between the chain and the sprocket.

I also re-adjusted the chain (1 inch chain slack, rear wheel at same "tick mark"), wiped all the old grease off with a rag, and lubed it with some of this Dupont stuff: http://www.amazon.com/gp/product/B003OBP63S/ref=oh_details_o03_s00_i00

Anybody know how to fix this?

Does your noise sound like this? I got this noise when I did my sprocket swap. I don't remember it being there before.

http://www.youtube.com/watch?v=YYyaxlMNkqs&feature=youtu.be

Does your noise sound like this? I got this noise when I did my sprocket swap. I don't remember it being there before.

http://www.youtube.com/watch?v=YYyaxlMNkqs&feature=youtu.be

This is exactly the sound! What is causing this?!
Maybe it is because we both have blue bikes.

OEM countershaft sprockets have a large disc on each side of the sprocket. Sometimes the extra width of the sprocket also has a thin rubber cushion. This is designed to quiet the chain noise. Unfortunately, most aftermarket sprockets do not have this feature. Your new sprocket will work just fine but it will be, more noisy and may not last quite as long as the original. Hope this helps. :D

This is exactly the sound! What is causing this?!
Maybe it is because we both have blue bikes.

sounds like bad chain alignment.

I think it's normal.

first...anyone got links to where i can get the sprockets?
and second...taking a chance at sounding like an idiot...does anything have to be done with the chain? or SHOULD there be something done with the chain...i read somewhere on another post something about a 415 chain? =/ so im just seeing what i need all together to make it the best output...

I was thinking about doing the 15t front sprocket over the winter. My only worry is about riding on the track. I know that the 15t will lower my acceleration in 1st, but will it make much of a difference if I end up doing track days this summer?

I was thinking about doing the 15t front sprocket over the winter. My only worry is about riding on the track. I know that the 15t will lower my acceleration in 1st, but will it make much of a difference if I end up doing track days this summer?

First off... Keep all your sprockets if they are in good condition, you just may need them later.

I ride track with a 15t sprocket. Depending on the track it may help or hurt. I mainly run my 250 at Putnam Park in IN and it lends itself very well to a 15t front because it keeps the bike in the power band longer and with less shifting between corners and such. Other tracks, maybe stock gearing would be better. For Mid-Ohio, I like stock gearing better because of the "drive corners" even though I am slower in the back straight.

If your NOT good at keeping the bike between 8k and 12k rpms, it can hurt you in the long run. It will help you if you are proficient at swapping them out. I don't always know what gearing to run on a new track or maybe I am feeling more/less aggressive that day.

Many factors go into keeping the bike really dialed into the powerband. Getting entry speeds right and being in the right gear at the right time just to name a few. It takes a while to build a relationship between the bike, track and rider. Once you have that, you can feel really good about selecting your gearing.

Ah alright, I really want the 15t for highway usage, but was a little worried that it would hinder the bike. But it sounds like the key is to just keep it in the power band.

Also, about switching them. I was going to have someone do it for me, but maybe it's better to learn to do it myself huh?

Dude, it takes 10 minutes. Don't pay someone to do it for you.

Like Chris said, keep an extra sprockets so you have more options.

At Mid-Ohio, I was running 14/47 gearing; nice to rip out of corners, but I was having to shift like a mad man everywhere else and really make sure I was in the right gear on corner entry. I switched to 15/45 and really like it for commuting/general fun riding. I'll likely run the 15/45 next time (and keep it reving) I'm there, but take the 14/45 with me.

Why would you need to follow this DIY? When you take a peek at your sprocket and it looks like this:

23117

Is it just me or for those of you that changed the sprocket had a very tough time aligning the teeth of the sprocket with the spacer side facing in? I can't seem to get on properly. It's super easy put the sprocket into its place with the spacer facing out but when I turn it sound and have the letters facing inwards, It's nearly impossible. Don't know what I'm doing.

Is it just me or for those of you that changed the sprocket had a very tough time aligning the teeth of the sprocket with the spacer side facing in? I can't seem to get on properly. It's super easy put the sprocket into its place with the spacer facing out but when I turn it sound and have the letters facing inwards, It's nearly impossible. Don't know what I'm doing.

I don't think you know what you're doing. I just did this on Monday and it went in fairly easy. I do have the JT 15T though. Maybe you have a vortex or something else?

I figured it out, i had to line up the teeth perfectly before sliding it and i had to slide it in perfectly straight, if it was a little bit turned/angled, it wouldn't go in. just changing the front to 15T doesn't really make too much of a difference. I'll have to also change the rear at some point. there is a little drop in RPM but i wished there was more.

So do you have to change out the chain and the rear sprocket if you are changing out the front sprocket? I have read the the wear characteristics on the chain and rear sprocket will be compromised if you put on a brand new 15t front sprocket. Anyone know if you have to switch it all out if you install a new one?

F.Y.I I have 4500 miles on the factory chain and sprockets

So do you have to change out the chain and the rear sprocket if you are changing out the front sprocket? I have read the the wear characteristics on the chain and rear sprocket will be compromised if you put on a brand new 15t front sprocket. Anyone know if you have to switch it all out if you install a new one?

F.Y.I I have 4500 miles on the factory chain and sprockets

If you don't see noticeable wear, don't worry about it. You'll still get lots of life out of it, and can always switch it all out next time.

Ok, so today I tried to change my sprockets and chain.

I haven't been able to remove the front sprocket cover. I removed the three bolts and the shifter linkage. I could move the upper port of the cover, but the lower part seemed stock there. Is there some kind of "hidden stud" next to the lower bolt (on its right)? I tried applying force with a bar but nothing wanted to move.

Anyone had this problem?

Thanks

Ok, so today I tried to change my sprockets and chain.

I haven't been able to remove the front sprocket cover. I removed the three bolts and the shifter linkage. I could move the upper port of the cover, but the lower part seemed stock there. Is there some kind of "hidden stud" next to the lower bolt (on its right)? I tried applying force with a bar but nothing wanted to move.

Anyone had this problem?

Thanks

My guess is one of the metal alignment dowels are just a little stuck.

Thanks headshrink,

I'll ask my friend to put some liquidwrench in that area, to let it work until next time... Hope it will loosen that alignment pin...

Thanks headshrink,

I'll ask my friend to put some liquidwrench in that area, to let it work until next time... Hope it will loosen that alignment pin...

No problem. It may be difficult to get liquid wrench in the right spots, but you might want to try tapping the sides of the cover to see if that breaks it loose. You can also VERY CAREFULLY see if you can twist a screwdriver under the cover to pry it up a smidge. You just want to break the grime. Be super careful though, because you don't want to bend those dowels. Also, if you haven't already, when you eventually get it off you'll see why most of us switch to chain wax.

Looking for faster acceleration. Would a 13 t front be a noticeable difference? And do I need to shorten chain? Also does anyone have any links to a 13t front sprocket that is good I can purchase for my bike? And I am looking into a k&n filter to let her breathe better? Any opinions ?

More torque, yes. But IMO you would move through the first couple gears so fast that you may not feel like it. Shift, shift, shift slows you down a bit too. 15T is my preference because it smooths everything out and puts the shifting points where I intuitively feel they "should" be. It's personal opinion though, and for about $25 you can try a new counter-sprocket and not be out a lot of money if you don't like it.

I read on another board that 1T on the counter-sprocket is aprox. equal to 3T on the rear (not sure, just repeating). Assuming this is true, you could theoretically "fine tune" your gearing by making adjustments in the back too.

I read on another board that 1T on the counter-sprocket is aprox. equal to 3T on the rear (not sure, just repeating).

It's because the rear sprocket has 3 times the teeth of the front. (stock is 14/45, common mod is 15/45). Changing from 14/45 to 14/42 would be the exact same thing as going to 15/45; the reason people don't do that is because the rear sprocket is more expensive, and the chain length might be affected a little bit more.

Makes sense, thanks!

If memory serves, an additional factor is it becomes problematic fitment wise to add anything more than 1T to the front of our bike, thus the rear is changed. I don't hear too many people wanting this ratio, but I remember fitment being discussed in the early days.

Having a helluva time getting the front sprocket off of my Ninjette.. Looks like I'm going to have to remove my Musarri pipe and use the 2x4 trick to break it loose.. :/

I did manage to swap out the stock 45T rear sprocket for a Vortex 43T rear sprocket, though.. Maybe it's just me, but the difference is definitely noticable in how the bike rides.. It seems to be smoother overall.. I love it.. I'm hoping that when I go from the stock 14T front to the Vortex 15T front, it improves even more..

This is one of those times an impact wrench is best. Those who have been around a while may remember when I damaged my bike trying to apply more force trying to get that mother hugger off.

My oldest son is an Audi/Porsche mechanic down in Baltimore.. I'll probably enlist his services for this one, since I know he has all of the tools necessary.. Better safe than sorry..

When I got my Ninja last year (2012 out of crate new) I carefully broke in the motor not exceeding the rpm guidelines or lugging the motor . I had stock gearing. Upon coming up to my first 1,000 mile trip on her I changed out the stock gearing to 15/41 to lower highway rpms at 72 mph. The gearing kept the engine in the rpm range that I wanted but found that I could not pull any higher than 93 mph (GPS verified). If I was to do over I would probably look at 15/43, 15/42 which would help acceleration in top gears.

Overall I can't complain it's a minor inconvenience and really who cares if the top speed is 93 or 98??

Yes the front sprocket is on there. I put bike in gear had someone sit on bike and depress the rear brake pedal and I had a long 1/2" breaker bar.

Make sure you use a torque wrench and put the new sprocket back on properly. Good luck and enjoy the ride :)

I looked over various sprocket combinations to find the gearing that I thought would be best for my wants/needs.. The 15/43 *should* be the best overall option for my riding purposes, with quite a bit of highway riding mixed in with the usual suburban roads..