Wonder if you guys can help me brainstorm a problem

[RIDE-RED 250r]

My cousin has a liquid 250r that jumps out of 3rd gear. We disassembled the transmission to discover the shift forks showed signs of heavy wear. So, I took apart a spare engine I have and gave him the shift forks out of it that are in excellent condition. We thought for sure that replacing his worn shift forks would cure the problem, but it didnt. While we had his engine apart we noticed no other components in need of replacement. Shift drum looks very good along with everything else associated with the transmission. This one has us stumped right now. Anybody else have any ideas as to what could be causing this problem??
Thanks!

[just ben]

the detent arm and or spring that holds the shift drum in place

[RIDE-RED 250r]

Ok, thanks for the reply. Will check that when we get it apart again. Would that cause a problem with just 3rd gear, or all gears?

[atc500x]

Ok, thanks for the reply. Will check that when we get it apart again. Would that cause a problem with just 3rd gear, or all gears?

it depend how the drum shift is made,maybe this will cause a problem only on a gear or on all gear,can be different from a transmission to another.Are you sure the gears are in good condition? Habitually when a fork is bad the associateds gear need to be changed depend how long you use your trany with this problem.The teeth of the gear can be good,but check each side of the gear,and the gear that match to this one.

[RIDE-RED 250r]

Thanks ATC500x. I pondered that very question this morning. It makes sense that if the forks were shot then the sides of the gears the forks are in contact with would have to be at least somewhat worn as well....

[shortline10]

When replacing a damaged shift fork you always replace the 2 gears associated with that fork . Were the gears mesh with each other they get rounded off and wont catch anymore .

[Mosh]

All of these are good tips.

Also you want to replace the pins that hold the forks. They can get bent or actually worn and let the shift forks wobble just enough to pop the gears out.
You also want to check the main shafts for excess wear or runout too, and make sure all the shims and washers are good on the shafts, and also your endplay on the main shafts.

[RIDE-RED 250r]

Thank you all very much for all the helpful replies. Sounds very likely we should have at least swapped the 3rd gear set along with the shift forks. But, judging by the fact that all of his forks were very worn, I think Im going to end up donating the entire transmission out of my spare parts engine. I know for a fact that transmission is good. I think that might be the best way to help my cousin get his R up and running.