Throtrle Response

[striker1001]

I was warming up my EX this morning to change the oil cause im going to glamis soon. When i finished the oil change i turned it back on and started reving it. But when i did, i would push down on the throtle and it would like skip and then like a half second later it would start reving. Sometimes when i rev it it would kill the engine. Do i need to loosen the throtle cable or is something wrong.

[sixer3]

try taking the air-box lid off and trying the same thing, it may just need a little more air, oherwise u could have put too much oil in it, did that once(be careful taking the oil cap off :)) spark plug also, and the last thing to check would be a clogged or too small of a pilot jet, did u rejet lately?

[xx3003xrdrxx]

your either almost out of gas , or your motor was cold ......

[ride_red666]

mine did the same thing it was because it was out of gas

[m1ke]

quick question....

when i take my air box lid off it backfires?

[sixer3]

ya do to too much air into the mixture no big deal put it back on :) or rejet with it off

[duneaticdave]

i hope its not this. but i had the same problem too like a day or so before i went to glamis and i thought it was just old gas so i would burn through it out in the dunes. after a hour or so after riding, it started to loose alot of power like it didnt have any compression. evenually it just quit on me and it had oil coming out my exhaust not just a dripp but a handfull. BAD!!!! right know its in the shop and i found out that the piston cracked!!!! so now its goin to be a 440. but i also have to get new valve guides, rockers, and a new cam shaft. i just hope that this isnt your cass too.

it kinda sucks for me cause im only 14 and my dad wants me to pay for the whole thing and i dont have a job or any thing.
hes evil! look heres a pic of him> :devil:

[striker1001]

Well my EX is stock, so no i haven't jetted and yes its almost out of gas but not on the reserve just yet. Is it just possible im pushing the throtle to fast for my engine to respond cause i knid of pressed it quick and hard.

[400exstud]

Is it just possible im pushing the throtle to fast for my engine to respond cause i knid of pressed it quick and hard.

Yup. I am sure that almost all 400ex's skip, spit and sputter when they get warmed up. You are able to overload the engine by snapping the throttle down to fast for the cold motor to handle. You have nothing to worry about.

[m1ke]

Keep in mind these engines are carburated, not fuel injected. The carburated engines do not like to work unless the engine has warmed up, it's crutial.