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CR 125, best sprocket/chain set up.

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I was looking for some advice on a good sprocket size for the CR, probably a 52 tooth rear for more low end. Not sure about the c/s sprocket or what type of chain to get. Advice?

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I think most sprockets are about the same i've never been able to tell a difference in them. But yah get about a 52 tooth in the back and that should about do it.

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Isn't 52 stock? It is on the 06 any how,cuz I went up one tooth on the back to a 53,it made a bit of difference on the bottom end,donno if I'd go to a 54 tho...

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I am not an expert, so went to the Renthal website and they have a good amount of info on it. In the 2001, the stock setup is a 12 drive / 52 rear sprocket. I went back to that after buying the bike and riding it once with a 13 / 49 which I thought had WAY too much top end. The stock 12/52 had WAY too much bottom end, so going to go back to a 13 drive, but keep the 52 and that should be somewhere in the middle. Unfortunately, its something you just have to try, etc. and see how the engine pulls, your riding style, etc. Good luck.

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I was looking for some advice on a good sprocket size for the CR, probably a 52 tooth rear for more low end. Not sure about the c/s sprocket or what type of chain to get. Advice?

I also bought Renthal sprockets and DID Gold 520 chain. Maybe overkill, but I am a fun rider not a racer, so don't expect it to wear very soon. I don't ride enough.

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I am not an expert, so went to the Renthal website and they have a good amount of info on it. In the 2001, the stock setup is a 12 drive / 52 rear sprocket. I went back to that after buying the bike and riding it once with a 13 / 49 which I thought had WAY too much top end. The stock 12/52 had WAY too much bottom end, so going to go back to a 13 drive, but keep the 52 and that should be somewhere in the middle. Unfortunately, its something you just have to try, etc. and see how the engine pulls, your riding style, etc. Good luck.

Stock setup for the 01' CR125 was 13/52. Alot of people like 13/53 gearing.

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Stock setup for the 01' CR125 was 13/52. Alot of people like 13/53 gearing.

Thanks for the correction. I don't know where I read that its 12/53 for the 2001, but going back to a 13 anyway...

CR125-drive-train.jpg

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Ive got a 1999 with a 13/52 setup and it works great! Good bottom end and still plenty of top end. The Renthal site says stock was 13/51, so I would say go up 1 in the rear. Run an o-ring if you're more interested in longevity and a non o-ring if you're more interested in keeping the weight down/racing. Just my .02 cents.

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Here's a chart I made for you guys. 2387447950103689355S600x600Q85.jpg

I have a 99 and I'm running a 14 50 and I hate it. POS is so hard to get moving. It doesn't help I built up the motor for top end RPM's. I don't really know which is stock I was just going off what you guys were saying.

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My boy runs a 02 CR 125 his gearing ended up being 12/51 ... too much bottom for me at 4.25 ratio I have a 07 and run the 13/53 combo 4.07 ratio  ... he digs it helps him pull outta the corners quicker, but really it's how ya stay on the pipe we run neck n neck an I got him by 75 lbs ya I'm too big for my bike but it's still fun ripping her around with all the old guys (+40) 

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