Keeps jumping in 3rd gear!?

[Wes350x]

We split my stock motor a few months ago and put a long rod crank and new seals and bearings... Well the bottom end came from a different motor I bought. Put it all back and it would jump out of 3rd gear only under decent acceleration.

Got my old buddy to split it again, take his time and check everything good.  He found that a shim was not there that sits on the case and a shift fork looked like it had recent wear. So we said...there's the problem. Well NOPE, put it back in and still jumping in 3rd. He is a very picky guy and said he checked everything against the manual and an extra tranny he had.

Not sure what to do.. I'd like a stick a stick of dynamite in the exhaust side and light it right about now!

[T8R6X]

mine did the same thing, the shift drum had a small crack in it letting the fork move took a while to find it, just a suggestion

[Victork]

I bet the shift drum is loose.

[johnny22]

Mine used to jump in first gear and it was a worn shift fork. I do know that in a yfz if it starts to jump in third it is the clip in the tranny that holds the gear where it is supposed to be

[Tbone07]

I'd make sure you are absolutely positive that all your transmission gears are from the same model year. If you pull up a microfiche from Service Honda or wherever, it should list the amount of teeth on each gear given the specific model year. Especially if you're swapping parts out from a spare bottom end.

I almost made that mistake when re-assembling my transmission

The shift fork/drum is also a probable cause.

[Oppossum]

I had the very same issue many years ago after a total fresh build. during the initial "ride" break in, once you got to third it would jump out of gear when you throttled it and would repeat each and every time. the problem with mine was the two 8mm bolts that hold the shift drum tabs were backed out ever so slightly. after lock tite, re-torque and reassembly of engine, all was well.

[Wes350x]

We will eventually get the time once I calm down some to re-split it again and check all that you guys are stating.  The forks are all great, Im 100% sure on that.  Ill be sure to look at the drum and all gears seperately. Just gotta cool off first and not have sledge hammers near me once I decide to do it!

[jamieg45]

Yah these old toys of ours can be very frustrating at times, been there a few different times when I was racing and not to long ago after a greatride. The bike ran awesome but the next weekend I went to silver lake and the bike would start and idle fine and rev up, but had no power to ride it at all at full throttle. Got it home and started playing around witthe electrical and swapping pieces and found out my, stator, coil and cdi all went bad at the same time. Keep your head up man and you will get it all figured out, it just takes time.