[Kyle450x]

Hey Everyone,
I finally took my transmission apart from pre-running Baja last October when I encountered transmission issues so I loaded her on the truck and used the back-up bike.

While riding in 5th gear under some load the transmission suddenly lost drive (as if I was in neutral) and them slammed back into gear. I am still unsure as to what could cause this...

Symptoms of transmission: 1st through 3rd: golden.
4th gear: would pop out of 4th gear and into 5th or 3rd under any kind of load.
5th gear: almost impossible with high gearing as you have to shift from 3rd to 5th and feather it.
Overall, all gears were very hard to shift through at the shift lever.

So with that said, looking at the transmission gear shift drum there is a notch of metal missing from the center gearshift drum track, and the center gearshift fork appears to have been grinding on the gear track a bit.

4th and 5th gear of the mainsheet assembly show some gear pitting as well (odd that that didn't translate into the countershaft gears?).

Does anyone have any input as to if this (seemingly small) damage could cause such symptoms? I was expecting to see missing teeth from gears etc.









Hard to shift through gears: my theory is that the primarily the center gearshift fork is bent.

I don't really see why 4th gear continues to pop out of place though.

[Kyle450x]

Small update: I noticed that the dogs between 4th and 3rd on the mainshaft are worn. About 1/2 of the dog height is worn away. What causes this?

[Aussiecrf230]

If the drive dogs are badly worn this will result in the gear not staying engaged. With the drum missing metal that probably provided play that started the problem. Either that or the dogs were already worn through shift problems and have spat the gear sideways damaging the shift drum.

The gear tooth wear is normally in the middle of the tooth face whereas yours is on one side which suggest gear not aligned/fully engaged. Once again can be related back to play at drum. Were 4th and 5th gears replaced in the past?
Had the gearbox had any other work?

Normally anything but the smallest amount of play in gear being locked in position can result in it dropping out of mesh. Under load that normally makes a mess of some part.