Hi people, my dads 400EX is only about three months old. After riding the bike for about twenty minutes, it begins to cut out periodically with a load on the motor. (Usually going up an incline at lower RPM's and at about half throttle.) It feels like a fuel problem. Has this happened to anyone else? Any help would be greatly appreciated.

00 Banshee

 

maybe you just need to shift down

00 trx400ex - ac mudscreen front bumper, nacs headlight covers
86 trx200sx - powersport bandit 20 in rear tires

http://www.geocities.com/cory_14/

 

I dont mean to sound like a smart ***, but are you pulling the choke all the way off....


Eric

 

This has occurred on my '99 twice in the past two months. I blamed it on the White Brothers rev limiter. Maybe it was not.

 

If I were you, the first thing I'd do would be to read the plug (a new one, to avoid a contaminated reading) after riding at 1/2 throttle if that's where you get the problem. You may be a tad lean on your needle jet. If your read indicates a lean condition, raise the needle one position from the 3rd, or center one & re-test. If the problem still exists, I would return the needle to the 3rd position and go one size fatter on the main jet. There is some overlap in the three jet circuits so they aren't precisely defined. The pilot controls fuel flow from idle to 1/4 throttle, the needle jet from 1/4 to 3/4, & the main from 3/4 to full throttle, again, with the above mentioned overlap possibilities.
P.S. Agfter re-reading your post I notice that you mentioned it seems to occur only on an upgrade; if the jetting hasn't resolved the problem you might check the float level & also the float needle to be sure they are both operating smoothly & that the float level is up to spec. On an incline, if the float level is not up to spec you could be starving the engine of fuel.

 

my cousin had that problem and i notice it on mine, more like a flat spot i think, a k&n and jet kit fixed her right up

 

if you have a whitebrothers rev kit and your battery is not at a full charge it wont have the current needed for this mod put stock box back in

 

I had the same problem with mine also. Every now and then it would cut-out and occationally stall if I tryed to take the motor above an idle. It was dirt in the jets, I took my carb apart and gave it a good cleaning and installed an inline filter, I haven't had any problem with it since.