I have a similar issue with my '84, but with a standard tranny. Although mine always either starts or grinds - it never does "nothing". Sometimes it will grind 1-3x, and then start on the 2nd - 4th try, sometimes it will start on the 1st try. Once, with my mechanic friend helping me getting it into better running shape, we push rolled it a few feet while in neutral and I popped the clutch, then it started right up. Question - I know the rear main seal is leaking - it's pretty oily down there, would that contribute to the grinding problem at start up? I didn't think to ask my mechanic friend at the time this question... Or, if it is what drinkypoo suggests - either a missing flywheel tooth, or a sticky pinion, I should consider installing a new flywheel if the former, but how does one resolve the problem of a sticky pinion?