Sounds like the starter solenoid is not engaging far enough and starter is spinning before it is fully engaged. check and tighten all cables to battery otherwise may need starter rebuilt or replaced
I have had my 1990 bike from new and suffered similar problems some years ago. There is no lubrication in the starter, my problem was the starter clutch, which I replaced. Was pretty straight-forward and the same starter is still working OK with my recent new S&S 107 motor!
Sounds like the starter solenoid is not engaging far enough and starter is spinning before it is fully engaged. check and tighten all cables to battery otherwise may need starter rebuilt or replaced
Thanks a bunch for above. I cleaned terminals and it seems a lot better.
One other thing to check, your starter bolts may be loose. It's not unheard of and one of two things happen when they are, you either get nothing when you hit the starter button or, you get a grinding noise. Check them out as well.