[paynep]

Assuming that you have a 2-into-2 system, the Monster 620 ones can ground out while I don't think anyone has had a problem with 620Sport ones. Dunno about Monster 600 though?

Also I never had a problem with 750ss headers on road or track and I think I've got a set of 750ss ones which will fit a 600ss if you need a cheap fix

Alternatively if you only have a 2-into-1 std system the back of your bike is too low or the spring is too soft or the shock is knackered...