Hi guys, i'm wondering if anybodyelse that has ever installed a 640cc kit on his XR600R has nitticed that vivbration. I got a used NX650 dominator cylinder that i made bore to 101mm and got a 10:1 wiseco piston. The bike goes very well, but as the rpms reach 4000rpm or so it vibrates a lot, then after 4k it seems that it softens a bit and at around 7000rpms you can feel the vibration harder again. It's because the stock XR piston and the wiseco doesn't weight the same or what? Should i take it apart and grind some material away from the new wiseco piston to make it weight the same as the stock XR??? Or that vibration is normal and can't be softened? Thanks a lot.