I'm going through my 125 motor for the first time. Noticed some marks on some of the gears. Looking for feedback on how bad they look, as I have never had a bike's gears look like this on a rebuild before. For those that have done a lot of motors, is there an acceptable level of marking on transmission gears? Do the marks on the attached pics warrant a replacement of gears? There are a few that have marks like the ones in the pictures. I am sure if I threw them in, they would work for awhile. But the marks are a bit concerning to me. What do you guys think. I'm trying to determine what gears I need to replace if any.
Is it making any strange noise, or kicking out of gear? If not, I would probably run it. The good news, if it is a Honda RS125, that is a cassette gearbox and removable without without splitting the cases.
It never had a problem shifting. And no weird noise. Think I'll change the one where the corner edge is marred a bit, but run the rest of them. I do love how the motor is set up with the gearbox. Thanks for the input.
I would replace them. They have had a chip run through them, but the flaking on the dace of the teeth is a trouble sign... much cheaper tonreplace them now than when they loose a tooth and it bends shafts or busts cases!
I would look for any debris inside the transmission area. If none is found, then replace the damaged gears and be done. It really looks like foreign object debris (FOD) damage, not wear. If no more debris, then no more issue. Don't be concerned, be proactive. And maybe get a magnetic drain plug.
I see that wear on differential "spider" gears a lot. I'd replace them. We believe its from material in the oil as a spider gear only rotates when there is a mismatch in tire speeds, not nearly what a gear in a transmission sees.
Thought best to play it safe. I'm going to change all the marked up gears out. I know I would just have it in the back of my mind every time I jumped on the bike. Never found any debris as I was going through the motor. There definitely wont be any in it when I put it back together. There is no price for peace of mind. Thanks for all the input.
