high rpm sputtering

[Todd730]

I adjusted my valves and when i took my quad for a ride it is breaking up and sputtering at about 3/4 through full throttle. I think my timing might be out of whack. can anyone help me out please!

[cals400ex]

there is a good chance your jetting is off. if you messed with the timing, you better double check it. it is possible that the main jet is the wrong size, the mainjet fell out, or the two skrews holding the slide in the top of the carb fell out. i would also make sure you adjusted the valves to the correct clearances.

[400rednEX]

dirty air filter or loose intake boot?

[cals400ex]

yeah, i forgot to mention possibly an air leak.