question about loss of top end power

[buckwild]

hey,
i was riding the other day, and while going down a hill i heard a pop and the 400ex cut off like i had let off the clutch(but i hadnt).
well after that i noticed that there was loss of top end power (hard to pull steep hills etc) however it will still start and idle normal and there are no mechanical noises. also when in higher gear now (5th) full throttle it feels like it is in the lower end of third. again all top end is gone. also i changed the air filter, spark plugg and oil. just trouble shooting the old plug apperared normal. please reply im in serious need of help
thanks ahead of time
shawn

[rsimmons_82]

sounds like clutch problem to me. sometimes when a clutch breaks or wears out, the slippage will make it feal underpowered.

[rYan01400EX]

What the guy above me said sounds like a reasonable answer. I asked dad, he works on motors, and he said that his answer sounds right, however, it could be other things.

[cals400ex]

if it revs but doesn't go any faster, it is probably the clutch that needs replaced. does it want to miss or studder when your at full throttle now?

[buckwild]

no it doesnt miss or anything its like at part throttle it seems ok mabey a lil weaker but when i push it do full throttle there is no more power or top end. also when in neutrual when i push the throttel in fast it hesiatates and doesnt rev up quick
thanks for the replys so far please keep em coming

[buckwild]

o and no it does not rev high at all when at full throttle while in motion

[rYan01400EX]

Is your throttle cable stretched, out of adjustment, or anything?
Choke sticking? This sounds like a carb related problem. It seems maybe a float is sticking or something inside the carb is. Does it do like it does when you have the choke open, mash the gas? It dies down.. Then when you let off it goes back to normal until you mash it in again??

[cals400ex]

look at your spark plug and see what color it is. make sure the mainjet didn't fall out of place.