400ex wont stay running.

[Slowex]

I was riding my 400ex today and all of a sudden it started to sputter as if it were running out of gas. Then it was ok for another 30 seconds then it just died. If i turn the choke on I can get it to start for just a second but it wont stay running.

I pulled the carb off and its squirting fuel fine and i am not out of gas. Right before I went riding I adjusted my valves they were a little loose. I have recently been adjusting jets to get it to run best but it has been running fine. I dont think these actions are related. The jets are both brand new. Filter is new. plug is new. It was running fine just before this. Any ideas?

[tri5ron]

When you adjusted your valves, did you follow a service manuals procedures to a tee?
or did you do it from memory/experience?
Did you remove the timing mark plug and verify TDC?
Is it possible that it should be re-checked?

is it possible that the plug wire got cracked or pulled from the coil when you changed the plug ?

what size jets did you use, (also what brand), and what did you adjust the A/F mixture screw to ?

[Slowex]

If any of those things were done wrong I would think it wouldnt run fine for a while. Im going to clean the carb out.. maybe something got inside there.

[rocky_mtn_honda]

just thought i'd throw my .02 in...recently after my rebuild when i was out breaking mine in, i must have jarred come junk loose in the tank cause it all the sudden started dying with the petcock in the ON position, but when i switch it to reserve it runs fine no problem...so needless to say, im about to clean my petcock and tank out before this weekends ride...just another thing to check
good idea about cleaning the carb too, sounds like a circuit could be clogged somewhere

[coreo5]

float valve in the carb could be stuck shut. or stuck really close to shut

[wrekd]

Did you pull the plug to see what color it was after that happened?? When I rejetted mine it was a little too rich and it did the same thing and fouled the plug.

What you jetted it from and to might help us out a little also.