My 1984 Cal II decided it no longer wants to downshift, and the problem is internal. So I set out to pull the trans off. One swingarm pin came right out, the other was seemingly welded. I broke a pair of real good Allen wrenches and never budged it. Que the torch, as I'm short on patience with this kind of stuff. I got it red hot just to break it loose, it still wouldn't unscrew. I got it rocking back & forth about 1/4 of a turn, and that took a half hour. PB blaster & all that crap. So I got out the air gun and worked it back& forth for awhile, gaining a little each minute. When it decide to come out, it took all the threads with it. Wonderful. Now I'll have tap it out to something bigger & have my son the machinist make me a new piece to screw in there. There may be a better way, but I don't care about originality, and that's the easiest thing to do.