96 RM125 Not shifting Properly

[YZ250_#257]

Hi,

I am about to maybe buy a 96 RM125. It seems to be in pretty good shape other than needing a Clutch basket and fork seals. The other thing we noticed is that it won't shift correctly. When coming down from 3rd to 2nd it jumps back up to 3rd. The owner claims he has replaced the shift fork, and I believe him. But what could be happening? I have no experience that far in to a bike. Could the installer have messed something up to throw it off just a little? Thanks in advance.

 

[Hucker]

I'd see how the bike shifts after an oil change. Mine did the exact same thing, also sometimes shifted into a "false neutral" inbetween gears.. All I did was start using a 90W oil and the problem disappeared....

 

[David Trustrum]

Yeah well good luck but obviously the previous owner had some damage & he might not have fixed it all. There may be some damage to the shift drum. Or the gear dogs (on the side of the gears which mesh into each other when the gear is pushed along the shaft by the finger) may be bevelled. This pushes the gears away from each other -jumping the shift out.

This means replacement, or if it isn’t too bad a decent engine builder or engineer can recut the gear dog flat or slightly undercut it.

Nothing too hard to de but would do it soon in case it gets worse.