Cuts out under load

[yellow_ho_01]

here the problem, i can sit there and nail the throttle(in nuetral) and it revs out just fine... and does just fine in about 90% of the drag race type takeoffs... my problem is that say i go into a corner in a gear thats alittle high, it cuts in and out like(sounds the same as when you run out of gas, cuts on and off) but as soon as i downshift it works right, most of the time. I just got this 400 like 2 weeks ago, i checked everything out on it.. its got a 165 in it now,.. screw is at 3 1/2, i tried it at 2 1/2 but it did the same thing(of course) i checked the needle, now correct me if im wrong, but doesnt the needle in a jet kit usually have the size and other stuff marked on it?? this one has nothing on it at all.... the only time it does this is if im in a gear just alittle (should still run, maybe bog down, not cut out) high and i nail the throttle.... like its not getting enough gas..or maybe too much... OH another thing... until the quad has been running for like 2-3 mins.. when you punch the gas it blows alittle smoke,.. only when you punch it though... i was thinking this might be to rich... and also be the problem for the cutting out,.. too much gas??

sounds like your just riding in to tall of a gear ta me..

[yellow_ho_01]

but its not really that high... i meanits not like im up 2 gears.. plus i have a 14T on front.... it even does it if i stay in the gear,... after the speed picks up... it feels like water or bad gas.... but like i said it only does it when i said. When i downshift and it stops... the rpm's are higher then what i would normally ride trails at(when in the lower gear) is that too confusing??

you should check your compression.

If the compression is down and you need to power into a higher gear it just doesnt have the "power" to do it.

Why I first got my 400 (w/ims 440 kit) it had plenty of power to pull a higher gear. Since rebuilding the cylinder and rings etc I had a problem with a valve seat and it killed the compression. I am dealing with a proble like yours till I get the valve problem fixed. Till then it like to be riden like a 2 stroke in the power band/

Since you purchased the bike used you will need to get together some info and the compression is a good place to start.

[yellow_ho_01]

what should the compression be at.. ill try to find a gauge ASAP.. thanks... i knwo its kinda hard to tell by the feel of it... but as you might know to adjust the valves you need to turn the crank with a 17mm socket,... just by doing that it feels like it has plenty of compression... but i will find a gauge though,, thanks

I think the stock comp is listed at from 100-130psi.

Let us know what you find.

[yellow_ho_01]

just out of curiousity i took off my airbox lid, thinking i was running rich... i was right.. runs great now..... i was kicking *****!!! now i just need a new clutch..... any suggestions???

[TRX250XFIRE]

As i was reading though all the posts i was trying to think of things it could be, now my head hurts. lol, but its good it was just the air box lid,

i cant wait till i get my 400