3rd Gear Problem--Need a hand

[Z4J]

Newly rebuilt motor what was bought used, but in excellent cond.
Gears 1,2,4 & 5 work perfectly at all RPMs
Gear 3 works well until around 4000 RPMs and then it feels like the clutch is quickly pulled and released. It briefly revs high, but doesn’t grind and then goes again until you hit that 4000 RPM point. Almost like it’s jumping out of gear briefly and/or not fully engaged?

Clutch would be all gears right?

We pulled the engine and reviewed all the tran. parts. Everything look good and in order. Slight wear on the gear dogs, but nothing I’d think that would cause a problem.

Forks & drum are OK, but the primary fork for 3rd now has hit marks.

Stumped. Any ideas or has this happened to any other EX riders?

Are the EX gears so sensitive that minor gear dog wear allows them to disengage at high RPMs?

Gear shift plate?

Stumped! Thanks for the review and time.

[Z4J]

No replies mean maybe just this build?

[Ntensweapon]

http://www.exriders.com/vbb/showthread.php?s=&threadid=367744&highlight=gear+problem

[Ntensweapon]

The same thing happened to me last fall. It ended up being a worn dog on a gear. I also had one bent shift fork. I think I replaced five gears that looked questionable, and forks.

[Z4J]

Wow. Almost a direct copy Ntensweapon. Thank you for taking the time to post. Did you end up changing the gear? This is a little round, but I wouldn't think it'd cause the situation. Maybe it's just more del. can I though. Did yours look a little wore, but fine (if you changed and reviewed)

[Ntensweapon]

Well to my eyes it didn't look all that bad. Just like the edge was slightly knocked off the corner. I changed that gear and the ones adjoining it. Also like I mentioned before, if it looked questionable it got changed. Again along with the adjoining gear. I didn't want to take any chances. Splitting cases is expensive if you can't do it yourself.

I did take full advantage though. I ended up putting in a new oil pump, rings, valves, heavy duty studs new clutch, and had another session on the port and polish bench.

[Z4J]

And it was fine after that?

[Wheelie]

I replace 3rd gear in mine several years ago. The dogs were worn causing the same thing you're describing. No problems after fixing it, that was over 3 years ago.

[Ntensweapon]

Originally posted by Z4J
And it was fine after that?



I'll find out tomorrow....I haven't had it out yet. I'm confident in my engine builder. It should be fine for quite a while.

Wheelie thanks again for the encouragement before. I just didn't trust myself. Sometimes it better to have more dollars than sense.