After assembling and reassembling several times, found that the whole transmission would sometimes lock up. Slowly chased it down to the top fork on the shift drum seemingly hitting a rough spot in the channel and getting a bit rough, which seemed to lead to the entire tranny locking.
But as these were the "pin" type drum forks, there was really no good way to get that damn pin out. Yahoo group no help on this one, either.
Tried sanding the channel as much as I could and stopped short of busting out the Dremel.
But then as I was playing around, I ended up removing the retaining clip, moving the fork back and forth quite a bit, then replacing the pin. And viola, suddenly the binding was gone. I think that by removing the retaining clip it allowed the pin to shift in place a bit so that it wasn't binding. Theoretically...
But in the end, was worried that it may not really have solved the problem permanently, so decided to swap it for the drum that was in the Model Motor, which had a smooth action despite having a few rust spots here and there.
That seemed to solve the shift issue, but was also finding that when I tightened down the case screws, the tranny would freeze in place from pressure.
After a long process of elimination, realized two things.
One, you need the gasket in there to account for a critical millimeter or two.
Second, the case must close flush by hand first. If you're closing any gap at all using the screws, then it's binding on something. Usually jiggling it a bit will help it close up.
As always, can't forget the 3 thrust washers: mainshaft, countershaft, and kickstart.
