So it occurred to me that the clutch is running fine now, but as the plates wear, I'll have slippage again...the pressure plate will once again rest on the transmission mainshaft.
Therefore, I bit the bullet while the fork was off anyhow, and did some in-situ surgery to better meet the first half of Bob Newby's instructions when he found out about my clutch slip: remove 2mm from the mainshaft.
Avert your eyes now if you can't stand lazy, amateur hackery...I know the proper solution would be to disassemble the gearbox, put the mainshaft on a lathe, and turn it down. But since there's nothing actually touching the end of the mainshaft, I figured it only had to be roughly square. My only concern with the end shape, best I could see, was ensuring the smooth, snag-free operation of the pushrod. Next time the transmission is apart, I'll probably go ahead and get it touched up on a lathe for propriety's sake.
First, I covered the primary like a good operating room (or a Dexter kill scene...) using some foam packing sheeting pressed over the mainshaft. Then I used a combination of Dremel cutting wheels, carbide bits, and flap wheels to remove the requisite material, re-chamfer it, and smooth it all out. Going slowly and using my caliper's depth gauge helped me get it roughly even while working freehand; the flap wheel largely evened out the imperfections and made everything nice and glassy-smooth.
[ATTACH=full]74628[/ATTACH]IMG_20191219_111212278 by Mick Doul, on Flickr
However, the shortening of the shaft led to another issue...in clutch engagement, the ceramic ball I had on the end of the pushrod arrangement would now stand fully proud of the mainshaft, pinned against the adjuster screw. Though it's held in that position against six springs, it made me uneasy. There was still a potential for it to somehow slip out. So, I went to follow the second half of Newby's instructions: grind the pushrod end to a "bullet shape."
To do this, I set my drill up on the workbench with a clamp, with the rod in the chuck, and spun it while I worked a counter-rotating dremel flap wheel to round out the end, periodically stopping to test-fit it against the pressure plate adjuster screw. It only took two or three fittings before it was perfectly shaped.
[ATTACH=full]74629[/ATTACH]IMG_20191219_142642157 by Mick Doul, on Flickr
[ATTACH=full]74630[/ATTACH]IMG_20191219_143642542 by Mick Doul, on Flickr
Then, I attempted to re-harden the pushrod by heating to glowing with a propane torch, quenching in oil, and re-tempering with the torch till I got a blue sheen on the outside. (Per WikiHow instructions...) I've never done that before, and do hope I got it right. I figure I'll check for wear periodically and make a new section if I have to. (Any input welcomed!)
[ATTACH=full]74631[/ATTACH]IMG_20191219_145722341 by Mick Doul, on Flickr
Fits perfectly.
[ATTACH=full]74632[/ATTACH]IMG_20191219_150755234 by Mick Doul, on Flickr
Looks like I will need to get a new pushrod and make attempt #2, however, as the loss of the ball at the end of the arrangement makes it too short, overall. I could put the ball back into the pushrod tunnel, as seen in this pic, but that makes the rod-ball-ball-rod arrangement slightly compressible as the balls stack up slightly on each other when engaging the clutch. It works that way, but doesn't seem optimal.
I also found that getting the short inner segment out of the pushrod tunnel could be a pain. If I do another multi-piece setup, I'll make the inner rod a little longer and the outer a little shorter.
