Debating on whether to order 15t sprocket.

[wild-bill]

The bike has 950 miles and I ran it hard for the 1st time. At this point, I don't think the ninjette has enough power to pull a taller gear ratio, especially at freeway speeds. But the engine is prolly still tight. Back in '99 I had a DR650 and it did not "loosen up" until the bike had about 3,000 miles. It would go about 10mph faster after the 3k point. So maybe I shouldn't make a final decision yet. But if I change it, I want to do it as soon as possible 'cause I know a new sprocket with a chain that has some wear is not good. Should i go ahead and order the 15t now or wait? What would you do?---Personally, I don't mind shifting into 2nd so soon or turning 9,000 RPM at 70mph.

[slolane]

Best mod I did

[JMcDonald]

GIve only ever heard one person report regretting going to a taller ratio. I love mine, with it being one of the tallest anyone has done on this bike (someone has a 15/38 setup I think, which is another 1% taller), and im actually considering going taller with some power mods.

Use www.gearingcommander.com and compare numbers with your riding preferences. Also, searching or even just scrolling through this forum will net you tons of info and opinions.

And FWIW, performance isnt technically reduced, but instead just *changed*.
Posted via Mobile Device

[gfloyd2002]

I was tempted by this mod, but there are no freeways in the country where I live, speed limits top out at 50 mph, and my daily commute is trafficky.

So for me, its all about torque and 0-50 mph runs, over and over. There is no need to lower RPMs at highway cruising speeds at the cost of reducing revs and torque. (I've even heard of track racers moving to 13 tooth, which seems crazy.)

I'm a bit of an extreme example, but the answer depends what you use the bike for and how you want to optimize it. Freeway riding or use the bike for touring? Then go for it. You want the low end pull for getting up hills or around town? Probably not.

[JMcDonald]

I think it might have been RacerX who reported faster 1/4 times after reducing the rear sprocket incrimentally from 45t down to 41. Based on his discussion of it, anywhere from 41 to 43t rear would be ideal for acceleration for most riders. A 15t front would be right around 42t rear.

90% of the reason I did this mod was for the longer lower gears, ESPECIALLY 1st. Calmer highway riding was just an added bonus.

Btw, changing sprocket ratios does not reduce peak thrust, but instead just moves it around.

Posted via Mobile Device

[gfloyd2002]

Originally Posted by JMcDonald

I think it might have been RacerX who reported faster 1/4 times after reducing the rear sprocket incrimentally from 45t down to 41. Based on his discussion of it, anywhere from 41 to 43t rear would be ideal for acceleration for most riders. A 15t front would be right around 42t rear.

90% of the reason I did this mod was for the longer lower gears, ESPECIALLY 1st. Calmer highway riding was just an added bonus.

Btw, changing sprocket ratios does not reduce peak thrust, but instead just moves it around.

Posted via Mobile Device

I'm no mechanic, but I'm struggling with the physics of this. Bigger front and smaller back both mean more top speed less acceleration. There will be less pull because of the gearing. I get the highway benefits of lower revs and less buzz, but how can that mean faster quarter times? Is it just based on fewer shifts needed b/c of longer gears?

[gfloyd2002]

Thinking more about this, longer first gear especially could make up for 7% additional leverage needed on the 15, just not at all intuitive. Current 1st is pretty useless in getting off the line and going.

[Yasko]

Originally Posted by JMcDonald

GIve only ever heard one person report regretting going to a taller ratio. I love mine, with it being one of the tallest anyone has done on this bike (someone has a 15/38 setup I think, which is another 1% taller), and im actually considering going taller with some power mods.

For what type of ridding?

[HKr1]

I wouldnt feel comfortable just changing the front sprocket, without adding to the chain or doing the rear sporocket also. Who wants to move the rear wheel forward, farther rear would be better..... if I had to choose.

From playing on the other bikes, changing a tooth on the front and rear kept the axle in the same spot.

[JMcDonald]

I think moving the rear wheel forward would technically increase turning response, but dont quote me on that. And really, I bet less than 1% of riders could really tell the handling difference between even the full range of adjustment.

Changing the sprocket ratios does not reduce the overall acceleration capabilities of the bike. It just moves peak acceleration and spreads the average acceleration out over a relatively wider range of speeds. Dont think of it like you have to be in the same gears at the same speeds, regardless of how the sprockets are changed. Think of it like you just need to have it in whatever gear that will put you at a useful RPM for your given speed. So, for me, if I need to accelerate from 50 to 65, I would just keep it in second and have the exact same acceleration as a stock-geared bike in 3rd (my 2nd is basically identical to stock 3rd). Yeah, if i was trying to shift at the same speeds as stock it would be much slower, but shifting must be based on revs, not vehicle speed.

Yasko, I do all sorts of riding. Most of my comuting is surface streets with stoplights and such. Most of my fun riding is up and down the interstate hitting all the onramps and offramps.

Stock, I hated first gear so much that I would do everything I could to stop in 2nd so I wouldnt have to bother with first. Even now I occasionally stop in 2nd (which is like stock third) if I will be going on slower streets or hitting multiple stopsigns. Off-the-line performance was much improved after tuning the carbs, though.
Posted via Mobile Device

[HKr1]

Originally Posted by JMcDonald

I think moving the rear wheel forward would technically increase turning response, but dont quote me on that.

Too late,,,,,,,,,,,, quoted. Moving the rear wheel forward "FOOKS" up the high speed steering. You can keep that sheet!

Did I read the rest of your psot? NO! Where's my glass of RUMM !

[JMcDonald]

Lol wtf?

I am just going by the uninanymiously reported reduced steering response resulting from extended swingarms.
Posted via Mobile Device

[Sailariel]

The primary reason that I went for the 15T Sprocket was intersections. I found it to be a PIA to have to shift to second gear in the middle of an intersection where I need maximum concentration and the ability to avoid a collision with some bufoon on a cell phone.

With the 15T, you negotiate the intersection safely by being able to concentrate on your surroundings and not having to shift. With the 14T, you were practically redlined coming out of the intersection. On the highway, the bike was a lot less Buzzy at 70+

[ungluck]

def wanna do this...would be great here...back and forth to the academy/waikiki for shift

[JMcDonald]

I would wholeheartedly recommend a 15t over the factory 14t to anyone who asked, regardless of what kind of riding they did.
Posted via Mobile Device

[highpsiguy]

I love the 15t mod. Still pulls me great thru town and thru the mountains. Dropped rpms at interstate travel. No plans to go back to stock.

[oroboros]

Mmmmm. Rum. I like Appletons rum. Reminds me of Jamaica. My next purchase 15 teeth.

Originally Posted by HKr1

Too late,,,,,,,,,,,, quoted. Moving the rear wheel forward "FOOKS" up the high speed steering. You can keep that sheet!

Did I read the rest of your psot? NO! Where's my glass of RUMM !

Posted via Mobile Device

[bella250r]

I love mine!

[Yasko]

My bike has 2700 miles on it. Would I have to buy a new chain if I add the 15t now?
Looking at this one.
http://cgi.ebay.com/ebaymotors/JT-FR...Q5fAccessories

Is this the right one for my 07?

[wild-bill]

Originally Posted by Sailariel

On the highway, the bike was a lot less Buzzy at 70+

My engine has some vibration from 7000-8500RPM. So if I went with a 15t, I would have to ride FASTER to get out of the buzz zone. At 9k, and even 10k, it's very smooth.

[wild-bill]

I ordered the 15 today. If I don't like it, it is reversible. What socket do you need? Is it by chance a 27mm? I had to buy a 27 to do the 650r front sprocket. But I went from 15 to 14 on that bike. Now it accerates quicker and i like the new 1st-not as much clutch slipping is needed to take off. I wish it had the ultra low 1st gear like the 250.

[Yasko]

Originally Posted by JMcDonald

I would wholeheartedly recommend a 15t over the factory 14t to anyone who asked, regardless of what kind of riding they did.
Posted via Mobile Device

Ordered mine today.

[JMcDonald]

I am pretty sure its 27mm. I had to have te GF go get me one because I apparently lost mine. When breaking loose, be sure to apply force in quick jerks / bounces, to reduce the chances of stripping / breaking anything.

Wild Bill, if you wish the 650 had a super-short 1st gear like the 250 so you could take off with less clutch use, I worry you might hate going taller on the Ninjette, heh.

Im still thinking of moving to a 16/37 combo. Would make first gear almost like factory second, heh.
Posted via Mobile Device

[almost40]

Originally Posted by JMcDonald

I think it might have been RacerX who reported faster 1/4 times after reducing the rear sprocket incrimentally from 45t down to 41. Based on his discussion of it, anywhere from 41 to 43t rear would be ideal for acceleration for most riders. A 15t front would be right around 42t rear.


Posted via Mobile Device

I ran my modded bike thru the quarter ALOT, when I used to goto the dragstrip instead of doing trackdays.
With 150 lbs on board (or less) the 41T rear (stock front) gave the best times. (3 run avg) The ability to rev 3rd gear nearly to the end of the strip makes it the fastest thru the quarter. I also gained quite a few mph on the top end. Mod the bike and it responds well to taller gears.

[JMcDonald]

Ah, sorry, then it was you, not RacerX .

[wild-bill]

Originally Posted by JMcDonald

I am pretty sure its 27mm. I had to have te GF go get me one because I apparently lost mine. When breaking loose, be sure to apply force in quick jerks / bounces, to reduce the chances of stripping / breaking anything.

Wild Bill, if you wish the 650 had a super-short 1st gear like the 250 so you could take off with less clutch use, I worry you might hate going taller on the Ninjette, heh.

Im still thinking of moving to a 16/37 combo. Would make first gear almost like factory second, heh.
Posted via Mobile Device

I use an impact wrench on the front sprocket nut. And I don't think 1st will be too tall on the 250 with a 15 tooth. There's a HUGE difference in the first gears on the 2 bikes. I hate 1st gears that are too tall, however. My ZRX1200R was like starting in 2nd or 3rd. But the worst I've had were the dual sports(KLR650 and DR650). Having a super tall 1st gear is no good for off road riding as far as I'm concerned. And those bikes are so heavy-I just considered them low cost street bikes with MX styling

[DaBlue1]

IMHO the 14/45 gear set up does not take full advantage of the power and torque of the engine. Anyone that has done a bigger front and smaller rear sprocket change can testify to the fact. The bike really comes alive because of it. I think you will like it.

A 15/ 41, 42 or 43 = nice all around performance, reduced cruising rpms, better mpg, stays in a gear longer, will still have decent acceleration above 4k with just a little more twist on the throttle. The bike should have come with a 15t front sprocket stock

I have a 15/42 set up. With it 6500 rpm is an indicated 65 mph and first gear is a lot more usable.

[JMcDonald]

Originally Posted by HKr1

Too late,,,,,,,,,,,, quoted. Moving the rear wheel forward "FOOKS" up the high speed steering. You can keep that sheet!

Did I read the rest of your psot? NO! Where's my glass of RUMM !

Well, looks like I wasn't so off base... but I guess you were just drunk .

http://www.gizmag.com/suzuki-gsxr600...sx-r750/16595/

Reduced wheelbase

Provided the weight is balanced correctly, a shorter wheelbase means quicker, more precise cornering - just ask a Buell XB12 owner. Suzuki has used its revised, more upright engine design to shorten the new Gixxers by 15mm without shortening the swingarm (which would reduce rear end suspension performance).

While it's true to say that chain adjustment will change the wheelbase even more than that over the life of a chain, 15mm is a significant modification when you're talking about bikes that are made to improve lap times by minuscule numbers. It should make the 600 and 750 even better corner-carvers than before.