Thanks all for the great help you all have provided. I have a new question.

I got my old 1986 TRX125 from my dad a few weeks ago and have been restoring it. After new gas, oil and plug, it cranked fine and runs very well after sitting in his garage for 8 years. I can't believe it.

However, I ordered both new sprockets (large rear and small drive) and a chain. I have a manual and it looks like I have to pull the sub-trans off (and all the gears out) to get to the flywheel and other trans to change the sprocket.

Question:

Has anyone done this on similar machines and is it involved as it looks?

Any insight or help/experience would be appreciated.

 

To change the engine sprocket, you have to remove the subtrans and the left side cover. Sprocket is splined and slides off the shaft (affter removing the holding plate on some models). To change the rear sprocket, you have to remove the axle. Subtranny is easy, better if you have the manual. Hope this helps some.
Denny