Need Help, Starts to sputter after 1/4 throttle

[Enojastic]

Ok, the last time I rode my 400ex was in september last year. I went and started it the other day and it seemed to be running normal, then i tryed to take it for a ride and anywhere after about 1/4 throttle it just sputters. New Spark plug and the last time I rode it, it was fine. Anyone have any idea whats wrong?

[ridesa02400EX]

did you put new gas in it? or is it the gas that was in there from last september?

[Enojastic]

Nope, same gas. I didnt think that was it because it idles fine and its only after 1/4 throttle that it starts to sputter. The further I push the throttle, the worse it gets.

[BADTRX400EX01]

Try new gas, then if that doesn't work, your jets are plugged with varnished gas, maybe the float bowl is caked too. Did you at least drain the float bowl last year?

[UglyMotha™]

if gas sit for a few months it gets all gummy and nasty and stick to things and glues things together and plugs holes and stuff so try takeing your carb apart and do a thurough cleaning and check you vent lines too

[MX250r]

Sounds like your parking brake is on and it is restricting it. Did that on my 400ex at the dunes and scared the chit out of me. Thats all it was.