Strange noise while accelerating??? Any thoughts????

[Y2KR1forfun]

Hey fellas, got a prob with my 00 R1. Lately I have noticed a strange knocking/clicking sound coming from the rear part of my bike when I am accelerating. Only happens some times. Seems to be coming from the tire area, maybe swingarm. It will click/knock once or twice from a standstill, as the tire rotates, but at no other times. I checked everything while on a stand, and it all seems tight. No play, no wobble. Axle torqued to spec, up against chain adjusters. Swingarm bolt tight. Brake carrier tight, caliper tight. I am going nuts trying to figure this out. I just dont want failure and following rear wheel lockup due to this while i'm hammering away. Almost sound like a hollow knock. Doesn't seem to be from the transmission. I tried to replicate the sound but cant . Only happens when I am pulling away from a stop. HELP!!!!!!!!!

[LDHR1]

check cush drive ,bearings and chain.

[1hander]

cush drive, or chain

[jhall78]

It dosent make the sound when hitting the back brake slowing down?If not it's your chain.

[Y2KR1forfun]

Dosent make the sound any other time. As I tried to check the problem further, 1/2 hour of stop and go in a parking lot, it seemed more noticeable. Definitely a metallic type sounding knock from the lower part of the bike. If it was from the chain, how on earth could a chain make a "knock"? As far as the cush drive, it would seem that that would cause 1 knock as it bottomed out, not 2 or 3 as the wheel rotates. If it was coming from the trans, what would cause the sound only on initial acceleration under load?
Oh yeah, in case it helps, it has 21000 miles on it.
Thanks again!!!

[BSR-1]

sounds like the chain.
a worn out or unlubed/out of adjustment chain can make a knocking sound.