DIY- Sprocket Swap

[CZroe]

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

[jaso]

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 ;+)

[setasai]

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.

[Buffalony]

Originally Posted by jaso

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

[assripp3r]

Originally Posted by hzrnbgy

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

[Vampyre]

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.

[Vampyre]

Originally Posted by assripp3r

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.

[andylawcc]

Originally Posted by setasai

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.

[kcaja1]

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

[Momaru]

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.

[trevor_shiggs]

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.

[trevor_shiggs]

Originally Posted by andylawcc

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-sprocke...62158&t=1&td=1 second one down. Is this wrong, I know it will work but is there a new gen one?

[Nemesis]

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.

[trevor_shiggs]

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.

[Momaru]

Originally Posted by trevor_shiggs

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.

[Fleshbazbo]

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.

[headshrink]

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.

[nit8690]

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

[headshrink]

Originally Posted by nit8690

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!

[CZroe]

Originally Posted by headshrink

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?

[headshrink]

Originally Posted by CZroe

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.

[CZroe]

Originally Posted by headshrink

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!

[headshrink]

Originally Posted by CZroe

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).

[CZroe]

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

Originally Posted by Fleshbazbo

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.

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.

[headshrink]

Originally Posted by CZroe

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 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.

[CZroe]

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!

[flynjay]

Originally Posted by CZroe

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.

[choneofakind]

Originally Posted by CZroe

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.

[CZroe]

Originally Posted by flynjay

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

Originally Posted by choneofakind

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.

[choneofakind]

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

[CZroe]

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.northerntool.com/shop/too...9025_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.harborfreight.com/12-volt...nch-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.

Originally Posted by choneofakind

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

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).

[headshrink]

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.

[CZroe]

Originally Posted by headshrink

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!

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?!

[headshrink]

Originally Posted by CZroe

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?!

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.

[CZroe]

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:

Originally Posted by Vampyre

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.

[headshrink]

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).

[CZroe]

Originally Posted by headshrink

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.

[Alex]

Is that edit correct at this point?

[headshrink]

Originally Posted by CZroe

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

[jack_bm]

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