YZ125 Gearing Question

[alphado]

I rode my YZ125 hard for the first time yesterday at practice. It seems to be geared too high, I was in second gear most of the time and had to go into first in the corners. It has a 13 tooth front sprocket and a 50 tooth rear, I weigh 225lbs, so I was thinking of putting on a 12 tooth front sprocket. In a striaght line drag race it goes good, but I seem to have a hard time keeping the revs up on the track. Any thoughts?

 

[flynbryan]

I would suggest adding about 2 teeth to the rear sprocket. I don't really recommend dropping the size on the countershaft sprocket.

 

[Jaybird]

I agree, leave your CS alone and increase size on the rear.
4:1 should be plenty. 225 is alot of meat on that bike.

 

[atc3434`]

I'm 215lbs on a '01 YZ125... I'm pulling 52 teeth on the rear, 13 up front. Seems to be working out perfect for me. Comes out of the cornors quick, good setup for me. Give it a shot. Oh yeah, and I"m with these guys, 12 up front probably isn't a good idea.