My bro just got his 400ex jetted and got the valves adjusted but now it noticably vibrates when decelarating and feels like it lost bottom end. What could cause this? it has a stage II cam, pipe, filter, and cdi. I also had trouble turning it on, would the cdi cause this due to a low battery? thnx~

 

you defently got a problem was the cam installed before they adjusted the valves, maybe it's a problem with the other after market stuff, far as the starting problem does it turn over any diffrent to slow or not is the engine noisy. it would be easier to fix this if I was able to be right there but cann't type back with more info