Just got '84 R80RT and find that the smoothness I associated with my '71 750/5 ain't there. Is there a retro fit of an older flywheel that's doable ? It was 40 years past when I rode the 750/5 and I loved the smooth after all the vertical twin buzz. And to think I passed on a Concord for this thing. The last thing I expected was a lightened flywheel at the expense of long distance comfort. Reminds me of how Johnson Motors had all the Triumphs set up for California weather which threw Western Pa. rain and sleet and mud rearward onto me because of those abbreviated fenders that looked so great in the Southern Ca. sunshine.
I know, I'll dip the wretched wheel into molten lead.
It's my humble opinion that from a pure manufacturing standpoint that the flywheel and crank are balanced together. That is, that weight is removed from certain areas of the flywheel to make up for inaccuracies in the crank. Think about it; the naked flywheel, having been manufactured on a lathe, is almost certainly balanced in its as-produced state. So the various balance divots in the flywheel must be for the crankshaft.
So there is an high probability that the only thing wrong with your bike is that at some point the flywheel was removed to replace something like the crankshaft oil seal, and not returned to its original position on the crankshaft.
The factory must have marked the mated and balanced pair. How one can determine the original flywheel position decades later is a question for folks more experienced than myself. But I hope this thought gives you some glimmer of hope.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Thanks for the comment, Wobbly. I left out the fact that the '84R80RT has a clutch holder instead of a flywheel if the OEM parts schematics are correct. It's a sheet metal replacement for the heavy FW. It's a trade off ----- better shifting, better accelerating in exchange for some vibes that wouldn't have even come up to my attention when I was 24. But now I'm fragile.
unkilmal
If the clutch carrier-flywheel is not in the correct position relative to the crankshaft, the OT will not appear in the window at TDC. A simple check. R80 is by reputation the smoothest of the post 81 airheads. It does not feel like the old bike but there may be a simpler answer.
Bob
My recent carb tuning efforts have led me to believe that your problem may simply be caused by the carbs not operating the same on both cylinders. It could be that one carb is dirty inside, or one carb is out of balance with the other. Whatever is going on, the carbs need to be working as intended to get the smoothest running bike.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
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