Need some help! Hesitation

[platinum350]

Ok, I have a 2002 400ex w/ no engine mods yet. The last couple of rides I have noticed my bike doing some hesitation, especially when I was really on it. It is very irradic and doesn't do it every minute. It's almost like I am running out of gas or my plug is fouling. When it happens I ease off the throttle let it idle a minute and it's cool. So, I changed the plug today and noticed it looked pretty normal w/ the exception of some slight white color on the metal hook thing that you gap. I am assuming I am runnig lean. Any suggestions or know why this is happening all of the sudden. This quad does not have that many hours on it. Thanks in advance for any help w/ this.

[nosliw]

done nothing to the motor so you didn't mess with jetting, right?

maybe your accelerator pump shaft is rusty or something...

take out the carb and clean er up

[mojoe2878]

sounds like your main jet may be partially clogged not letting you get enough fuel in the upper throttle positions. pull the main jet out and make sure it doesnt have any trash or build up in it.
make sure all the intake and carb. boots are tight and have no cracks.
may want to adjust the valves if its been a while.

[platinum350]

ok, I was thinking something seems clogged myself. I guess there is a filter on the petcock. I should probably pop that off and clean that. I just remembered that I bought a kerosene gas tank and there was no fuel screen/filter in it. Who knows maybe something got through into my tank. Is there a filter on the petcock????

[mojoe2878]

i think there is a screen filter in there.