While riding my '80 1100 the other day I noticed that it began making a humming sound from the right side engine area when I put the bike in gear. I took it home and put the bike on the center stand to see if I could hear where it was coming from. Didn't work. I couldn't hear anything unusual with the engine. I rode it a few more times. It also made a humming/grinding noise when I accelerated. The noise went away when the bike stablized at speed.
Now I notice that the noise is back and it occurs even when on the center stand. However, now when I run it on the center stand or street, it makes a humming noise when in gear and accelerated.
Yesterday, after a short ride, it made the same noises, the oil light started coming on even though it is full of oil and antifreeze, and it had crunching noises accompanying it.
My guess is that i have a clutch issue, a bearing issue, or combination of the two that will require dismantling the engine.
Otherwise, the engine seems to run smooth and it goes in and out of gear without problems.
Maybe the oil pump screen is clogged causing the pump to cavitate and make noise. The screen is accessible (with some difficulty removing the front screw) on the lower right side of the case, a rectangular plate with 4 screws.
I appreciate your response. Unfortunately I had to wait two weeks before I could work on the bike. I pulled the screen yesterday and did indeed find a lot of gummy, tar like stuff on it-no metal. I cleaned it off and put everything back together. I started it up and now have, what I think may be, cavitation with the coolant pump. At least, that's where the rattling soulds like it's coming from. Back to the garage later today.