Help me figure this thing out.

[3x440ex]

Either there's something wrong with the electical or the carb is screwed up......it runs fine until it gets hot then it starts sputtering and carring on, but only when i have the throtle wide open. I took the bottom off the carb today to change the main jet and didn't see any debre in the bottom of the float bowl. I wonder if i got water in the fuel tank? or maybe the pilot jet picked up something? :confused: :confused: Can someone help me out here? Thanks.

[JOEX]

I'm not so good at trouble shooting stuff like this....

May need some more specs on your machine....

It wouldn't hurt to remove the carb and clean every out. How's the plug? May need replacing too. I always look at the cheap stuff first:p

Joe

[cals400ex]

i would try the plug first. i am wondering if your rich on the mainjet?

[nakomis0]

Thats what happens when a CDI box goes bad.

Ussually after it warms up the bike will die, let it cool down and then it will start again. Thats the most common way they die.

Maybe yours isnt that bad yet, and it is providing weaker spark but not enought for the bike to die.

The best way to test it is to just borrow a cdi off a friends 400ex and see if it improves.

[3x440ex]

Thanks guys.......I already tried the cdi box, since i had an extra one, and it wasn't that. I have already replaced the plug twice. As for the jetting, i was running rich with a 175 so i went down to a 155, then it was lean, so now i'm tring a 165.
My mods on the motor are: open air box with w/b foam filter, fully ported head, wb mid range cam, stock bore and compression, wb pro meg exhaust. wb cdi box.
I wonder if a bad spark plug wire would cause it to act like this?