Re: 954rr 4th gear problem
Worn Drive Dogs can also be a problem, I replaced everything in my tranny and still have the same problem with 4th. It's the drive dogs in my case.
You can drop the shift drum and shift forks from the bottom of the motor, with the clutch pack pulled. The bad news, is if it's not that ( shift drum or shift forks), then the motor case will have to be split for the tranny to be removed.
You can either A. Pull the motor, which includes the entire rear swing arm assembly. I did this the last time, put it on a furniture dolly, and split the case that way.
B. Wench the bike up ( with the fuel tank removed), leaving the motor in the chassis, and flip it upside down ( still attached the hoist).
The latter was recommended to me by a motorcycle mechanic. I did A. and it wasn't that hard.