I have a 01 honda 400ex. it seems that that it doesnt cleanly shift in the higher gears. Could this be needing new clutches? also it seems to tick or knock in the engine but i have no idea what it is. any idea? also it seems to cut out like its not getting enough fuel in low and mid rpms. I do have a white bros slip on and im not sure if i need to jet it or not. Also the choke lever seems to vibrate to on when riding. How do you tighten this? please help