New here new to me 954 advice needed
 

Hi everyone new here new to 954's as well I've had a 95 900rr a 07 gsxr 1000 a 02 gsxr 600 stunt bike and now a 02 954 so I'm not new to bikes riding or mechanics, my bike isn't pretty but she sounds healthy no top end or bottom end engine noise but she has no 4th gear is sounds like a bunch of grinding when going into 4th I've passed it and 5th and 6th are fine my question is what's the easiest way to replace that gear or should I replace all transmission internals, she's getting setup as a high speed stunt bike/tire killer, I've never been in the bottom end or transmission of a bike but plan on getting a book and doing all the work if possible some guidance or knowledge would be greatly appreciated

The only drawback to the 954 is how often something like that requires splitting the case... And if you think it's the actual cogs - you'll have to split the case. I think I remember someone swapping out the drum without splitting the case, but I don't think he swapped the forks..... So I'd plan on splitting it, which means more money, time, and effort...

Replacing gears will require splitting the cases. The drum and forks can be replaced by removing the oil pan and clutch with the engine still in the bike.

My experience with gear problems involves a case split and complete rebuild.
If a gear/trany issue occurred, there is a good chance that "metal crap" has gone through the oiling system that can compromise the rest of the engine.
An oil filter "chop" might reveal lots of stuff.
Good luck!