Knocking or rattle under hard braking

[woodsrider300]

Just bought a 2015 300rr and rode it in a dual sport ride in Ohio. Noticed a rattle or knocking in rear of bike on steep down hills braking hard. Locking and unlocking rear brakes. Sounds like something loose in suspension linkage but checked all bolts and none loose. Anyone else having this happen? I bought the bike new so this was the first ride on it.

[GMP]

First, this is best in the chassis forum. Second, it's your chain. Every bike I have ever had rattled the chain during hard braking over bumps, especially with the clutch in as there is no tension load on the chain then.

[ricoyam]

I think the chain guard and lower rear fender slap around a bit too.

[Johnny Depp]

There is slop in the fit between the tab on the swingarm that the rear caliper slides on. I wrapped mine with inner tube and stopped the rattle.
This is not just a Beta thing, most all bikes have this issue.

[woodsrider300]

Don't think it is the chain. I can hear the chain rattle. This is more like a knock or a clunk noise that only happens on steep downhils. The chain I can hear rattling on braking and accelerating. And it might only hear 4 or 5 times on a downhill. U would swear something is loose and banging. Can't find anything loose.

[woodsrider300]

Found it. The swingarm bolt was loose. retorqued and problem is gone!!!