125m rebuild going badly

[Frankencelery]

I've been working on a 1985 125m engine rebuild for some months. The original transmission had a broken gear and shift fork, so I bought a complete transmission with drum and both sets of gears on Ebay. The vendor has been reliable in the past, and the parts looked in good condition. The unit was shipped all together, so it was easy to assemble, and I took the time to compare to the originals However, now that the cases are back together, I have trouble shifting through the gears. It wants to stick between a couple of the gears. I'm half-tempted to throw the whole thing in the trash, rather than crack the cases again.

If I'm spinning the shafts, it does better, but still gets stuck intermittently. Sometimes I can get all the way through the gears and back, but when it's not moving it's nearly impossible to get through the gears.

Any ideas what I should be looking for? Frustrated!!!!!!

[Frankencelery]

Well, I slept on it, and usually I feel better after doing that. Not this time. Here's what it looked like just before I put the cases back together. It's not like I didn't have things clean. I know this is totally unscientific, but can anyone spot anything? I really thought I had it right!

EDIT: I just found out something that surprised me. I was searching for some help on the forums, and I ran into someone who said the '84 and '85 shift patterns on the 110 were different. I thought maybe the 125m might be the same, so I looked up some parts and found that the shift drums are different! I wonder if I've mismatched some parts. I'm mixing parts between '84 and '85 engines! However, the transmission was complete, all from the same engine, or so I was told from the seller.

[Frankencelery]

Ok one more post. I've been guilty of talking to myself before, so here I go again....

I may be proceeding on a false premise here. People talk about shifting through the gears when an engine is not running. I've been proceeding on the assumption that it *should* shift through the gears, even without the shafts turning. Is this true? I just meandered out to the garage again to look at it, and I watched the way the little gears mesh together, and if gears aren't moving, or the output shaft is freewheeling the tabs in the gears that move into the holes of the adjoining gear sometimes don't mesh, and you're stuck. But if I hold back on the output shaft a bit, turn the main shaft, and then shift, the gears always click into place! Maybe this is all much ado about nothing????

[KASEY]

i am pretty sure that you have answered your own question!!!!! so i see no need to further add to the conversation ,, you may proceed!!!












yes , the motor really be running.. if you had completely mismatched parts it would not shift at all... :-)