Motorcycle Repair: sprocket, drive ratios, clutch springs

Question
I have a 2006 RM85L. I would like to replace the rear sprocket (47 tooth) with a 43 tooth to
lower the rpm. Besides Chain length are there any things that I will need to take into consideration?


Answer
Hi Joel,

Change the front sprocket to change engine speed (RPM). Change the rear sprocket to change wheel speed or overall top end speed.

Final drive ratios are 3:1 or three points on the rear sprocket to every one point on the front sprocket.

If the stock rear is a 47, go to a 44 point rear. Making changes to the rear sprocket otherwise is fruitless.

Always change both sprockets and drive chain as a set. Do the same with clutch plates and clutch springs.

You can find gearing calculators on line.

Respectfully,
Mark Shively