I had not seen Streethawk's thread before seeing it referenced here. I thought I was pretty thorough in reading this board. Dang.
I did see Ponyhawk's those years ago, and even referenced it in my thread.
Streethawk blames the worn shift fork for his gear wear, which I think is a reversal of cause and effect. Granted, if the fork was bent then fourth may not engage fully, causing excessive wear at the end of the dogs, but most of the shift fork wear is (I'm convinced) from the angle on the dogs where they mate causing the gear to want to push back out when torque is applied by the engine. The shift fork moves the gear over to engage the dogs, but the angle of the surfaces on the dogs tries to push the gear back out. The only thing holding it engaged is the shift fork, which has now become a thrust bearing, not part of its designed purpose.
There
are no thrust bearings on the gear shafts. Straight-cut gears do not apply forces along the shaft. The circlips and washers are not thrust bearings (as they were called a few times in Streethawk's thread,) they are simply retainers, or locators. But put on angle on those gear dogs, and now you
do have an axial force on the gear along the shaft, resisted only by whatever the next piece is; in this case, the fork.
My fork looked about like his, maybe not quite as thoroughly "machined," and I think the dogs on my 4th gear were worse than his. It was a complete surprise, as I'd had no issues with 4th other than an occasional false neutral, which I blamed on lazy shifting. It never jumped or slipped once actually engaged.
Thinking back, but not being bothered to go look again, I don't remember if he replaced the third gear parts as well, or just fourth. I put both entire shafts from my donor motor into my motor, all "new" transmission. If Streethawk replaced 4th without replacing 3rd, he can expect a repeat of that shift fork wear, because that angled wear on the 4th gear dogs would also have been present on the mating surfaces inside the third gear wheel. Not trying to be a doomsayer, but I hope more was done than just the 4th gear wheels....
He also got
much more carried away than I did with other stuff..... Yeah, I did a valve check while it was sitting out, but shock? Final drive? Starter? Pthpthpthpthpth on that! I had enough to do with the tranny shafts.
And had he waited until the motor was upright to put the clutch basket back in that would have been simpler. In an upright engine the balancer simply hangs in the correct position when the crank's at #1 TDC.
