Edited Date/Time
4/19/2026 5:09pm
Guys-
Finally getting going on my 2000 YZ250 rebuild, currently at the transmission part. Inspecting the trans I'm seeing some wear on the dogs and looking for advice on what can be reused and what should be replaced.
No weird marks on any of the forks.
FWIW, I did not experience any issues with the trans, but really want to take care of anything now while it's apart.
So that was the drive shaft, I figured I should replace 1st wheel gear, 5th wheel gear and 3rd wheel gear? Reuse 4th and second?
Now to the main shaft-
Thinking replace 4th and 3rd pinion? Reuse 5th pinion?
With a transmission, I have been told that there are gear mating issues on 2 surfaces. There are the gear teeth and the shifting dogs and their corresponding pockets. To resolve shifting issues, any visible disruption on dog or the pocket edge needs to be replaced as a pair. ( dog and pocket) Now from a gear running longevity perspective , the gears on both shafts that run together should be replaced as a mating pair. If you do all that you transmission will work awesome and your wallet will be empty. Shifting performance has always been my interest with transmission repair. Replacing dog and pocket repair has always done me well.
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It doesn't look like that gearbox has had any serious trouble.
3rd & 4th dogs on the mainshaft are the weakest point in these gearboxes.
I like to assemble those with an oiling hole in the 4th gear sleeve aligned as close as possible to the oiling hole in the shaft.
The dogs on your 5th / 1st gear on the countershaft look pretty ugly, but 1st gear usually doesn't have issues on these bikes.
Your shift forks don't look bad.
Thanks for the reply, that cuts down the parts list quite a bit.
How do you guys feel about rem polishing? There’s a company here in the northeast that will do it for like $250 bucks.
Polishing transmission parts can make a big improvement on shift quality, especially on a new bike or a bike with very low hours.
I don't know the going rates for that service, so I can't comment on that aspect.
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