From what I have read and been told by the guys here, is that our 13 tooth mod is really as far as you want to go down in the front. The tighter the chain has to turn, the faster it will wear out. I can't imagine how noisy that will be going to a 10 tooth. Are you opposed to going bigger in the back? You know it does the same thing. One down in the front is the same as three up in the back.

 

Good question. While I’m not opposed to going up on the rear sprocket, Kawasaki currently doesn’t have a stock larger one (apparently they are working on it..) Since its still under warranty, I thought I could match the power of the larger rear sprocket with the full coverage of a stock front sprocket.

I was also thinking that the stock front sprocket is cheap enough that it might alleviate the spacing and chain sync up issues that others seem to be experiencing with after market sprockets. Apparently they now have stock 13, 12, 11 and 10 at the "correct" thickness...

I thought my CR125R was only 10 or 11 teeth, but I’m not 100% sure.....

 

At only 10 teeth up front, that's going to be a really high ratio of 4.2. Stock is only 3.00, while the most that most people go to is around 48:14 45:13 or 49:14. These translate to 3.43, 3.46, and 3.5 respectively. Compare those to 42:10 which gives a rather huge ratio of 4.2.

Not saying you shouldn't do it, but putting 10 up front will dramatically change the gearing.

 

yeah, and I'm a bit worried about over tourqing the driveshaft as well as the "noise" that the chain would make moving so quickly around the front sprocket.

If I back into the gearing ratios you described with a target of 3.5, that translates to a 12 tooth front with the stock 42 tooth rear. Maybe thats the better way to go until they get their rear sprockets into production... (in a year I won't care at all, just nice to still have them pick up the bill via warrenty if it doesn't work out....)

 

Hey dirtsurfer, I don't think they'll cover sprockets and chain under warranty.

 

dirtsurfer the KLX300 uses the same rear sprockets as the 250 so just order the size you want for the 300. IMO I think your better off going the larger rear maybe about a 46 or 47 and new chain rather than smaller front. The KLX motor is better off using the torque instead of reving like your CR125.

 

The sprokets are all the same on any kawasaki dirt bike 60cc or above from 1987 to 2006,they all use the same rear hub.

[IMG]local://upfiles/1719/A411586EADF44850898A52C022B00540.jpg[/IMG]

 

Thanks for all the info and advice!! I think I'll go with the larger rear sprocket, maybe a 47 or 48 tooth to get the same 3.5 to 1 ratio...