Uh Oh! Whatz that noise?

I picked up an '81 KZ1000J (18k on the clock) this past Friday. It started and ran well when I bought it. I rode it around in an empty lot when I got it home as the brakes are not working. I started it again Saturday morning and everything was fine. Saturday afternoon when I started it, it developed a loud knocking coming from the lower left side of the engine. I thought it could possibly be a rod but the sound dissipates as the rpms increase. Also, when the bike is shut off, it sounds as though the starter is disengaging. Any ideas before I begin tearing into it? Or at least get me headed in the right direction. :side:

Sounds to me you know what it is, Perhaps a bearing? I have never really torn into one of these motors. Let me rephrase that. I have NEVER torn into one of these motors. (Much thanks to WiredGeorge) But I do have a good understanding of whats goin on inside em.(I mean a motor is a motor) If the noise dissapates as the rpms increase, it could be a bearing problem,or perhaps a oil pump. If the pump is weak, or the bearing clearances to great, the oil pressure will be low, as the engine speeds up pressure increases. The sound quiets up. Thicken up yer motor oil. see if that helps as it will cushon the clearances alittle, possibly raise the pressure. Its worth a shot

Drain oil, pull left cover (stator) check overrunning clutch bolts to stator and starter gear needle bearing.

Thanks guys!!! (Man, I gotta get me a manual but quick!!)