It is very easy to over crimp the master-link. Rear wheel up on stand, turn by hand and observe if any kink in that area of the chain. Chain whip that you see is due to being in gear with engine around idle rpm and no real load on the swing arm. Best to test drive, once you have checked for master-link over crimp or any kink in the chain. May just be lube required and I know that you said it is a new chain. You did fit a 525 and not a 530?
I find that sometimes, when the chain is too loose, it is almost as though the clutch does not want to release the gear when shifting from 2nd to 1st when stationary. Double clutch by letting the clutch out slightly and pulling it back in, helps address this or tighten the chain a bit.