PROJECT CRF50

When we decided to get new sprockets and chain I had to decide what countershaft and rear sprocket to get. There were a few things to think about.

The stock gearing uses a 14 tooth countershaft sprocket and a 37 tooth rear sprocket. Changing the tooth count on the countershaft has a greater effect on gearing than the rear sprocket because each tooth is a greater percentage of the total tooth count. Example: 1 tooth added or removed from a 14 tooth sprocket is a 7% change. 1 tooth removed or added to a 37 tooth sprocket is a 3% change.

With the stock gearing, first gear is geared very low. It’s really only good for starting out and uphill climbs. Gearing up using a SMALLER rear sprocket (larger countershaft) would allow 1st to reach a higher speed before the motor winds out but wouldn’t pull as hard on starts and uphill climbs. It would also increase top speed a little.

Gearing down by using a LARGER rear sprocket (smaller countershaft) would make 1st gear all but unusable except for uphill climbs, and reduce top speed a little. I thought about going this route thinking we could forget about first gear and make second gear able to pull well from a start. This was a good possible option especially with the extra power from the new pipe and air filter.

In the end I decided to stay with the STOCK gearing!

Surprise! Again, with the extra power Ben doesn’t even use first gear much. The bike pulls well in second so basically he uses it like a two speed (Note: Many pro motocross racers use a custom transmission with FEWER gears than a stock bike). The top speed remains about the same because the bike has the stock rev limiter.

The bottom line is that the gearing is really mostly determined by the internal gears of the transmission and there isn’t really much positive change you can make by changing the sprockets (this is assuming a near stock bike, not some monster motor, modded to the max bike).

If you’re looking for faster top speed you might gear UP a bit. If you’re looking for some real stump pulling low end or want to forget about 1st gear you might gear down a bit. The choice is yours. You need to go by your specific circumstances.

I hope this helped and not confused. When in doubt stay with stock!

TEXT AND IMAGES COPYRIGHT PROJECT CRF50 2008

You can now also use: www.HondaCRF50.com to get here.

RENTHAL FRONT SPROCKET

RENTHAL REAR SPROCKET