51 tooth rear sprocket

I recently changed out the rear sprocket to a 51 on the back (technical woods riding) has anybody else done this? I am asking because the chain is resting on the rear chain protector (just in front of the rear sprocket). I am not sure if this is too much or if there is an aftermarket guide I should be using. BTW, the chain tension/freeplay is adjusted adequately with a little extra freeplay. Any ideas are appreciated thanks


What bike are we talking about? XR600R? XR650R? XR650L?

and what front sprocket are you using?

Whatever the case, if the rear sprocket is so big that the chain is PRESSING against the chaing guide, it doesn't sound very good.

The guide is made out of some kind of heavy duty rubber (like the front chain slide on the swingarm) and it does the job, but it will wear out very quickly if the chain presses against it hard.

I'd suggest that you go to a 48 rear sprocket and drop a tooth in the front sprocket. The chain guide won't be a problem anymore and also it's much easier to switch the front sprocket whenever you want to go for high speed enduro.

...But that's only my opinion..... :thumbsup:


how do you like the 41mmFCR? how does it fit on your bike? I have one on a 650R... came from sudco , and the fit is bad, and sudco isn't much help!!!

Just wondering how yours is working?

Actually, I'm having some problems with mine. The carb is now 2.5 years old. Up until 6 months ago it was fine, but I'm not really bothered with these problems now as they are not related to power or throttle response issues. I'm having some cold engine behaviour issues, nothing else.

Generally speaking, the FCR made a huge improvement in throttle response and a small increase in power.

It's funny what you say about Sudco... I live on the other side of the globe from where they are and they were very helpful over the phone when I called a few times...

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