400ex won't stay running

[dan burke]

help: 02 400ex run good went to the dunes for 3 hrs,wouldn't stay running, had the carburater rebuilt $165.00 still won't stay running,ou of ideas, maybe some body has an answer.

thanks much:

[js600]

try cleaning out the fuel petcock

[dan burke]

thanks for your imput,we did that, cleaned the fuel tank etc ,didn't make any difference.

[the Z Man]

So, it starts for a minute, 3 minutes... just fires and dies?
How long before it starts again..
Is it getting spark when it dies or is it running out of gas, what mods you have, is there a kill switch.

[07400ex]

hey mine was doing that...i think it was juist a fouled plug i changed it and it runs fine.

[GPracer2500]

Check that the gas cap breather is venting properly.

[maxfior]

Did you find out what the problem was? Check the spark plug? Cleaned the carb? Let us know.

Max

[bartlettracing]

valves can do that .... have them adjusted
to lean pilot jet ....can also do that ...


will it restart right back up and run for awhile again ?

[440challenger]

make sure the pilot jet is spot less.
Of course that you have fuel..

On a worst case scenario, when it warms up your lossing compression... Doubt it.

Maybe people think cleaning the carb is just spraying carb clean in it. you have to take all the jets out and clean them with a small piece of wire...run carb clean throughout , and blow out the passages with compressed air. I always get jobs where people say they cleaned the carb and never removed the jets. if it will run off choke,,that is probably your problem.

[maxfior]

Originally posted by 440challenger
make sure the pilot jet is spot less.
Of course that you have fuel..

On a worst case scenario, when it warms up your lossing compression... Doubt it.

Maybe people think cleaning the carb is just spraying carb clean in it. you have to take all the jets out and clean them with a small piece of wire...run carb clean throughout , and blow out the passages with compressed air. I always get jobs where people say they cleaned the carb and never removed the jets. if it will run off choke,,that is probably your problem.

Yea, I agree, cleaning the carb means taking the whole thing apart. I've found this stuff at my local Napa to clean carbs, works great. It's in a 1 gallon pail and comes with this little dip basket. You lower your carb, or parts in there and let it sit while you run to McSlingers (McDonalds) and get a double cheese burger, when you come home, (after taking a trip to the toliet) you can pull up the little basket, spray off the parts with carb cleaner and blast it with compressed air and there is your new carb! The stuff is AMAZING! I had a carb off an 1974 CT90 that was so nasty, you couldn't even move anything, it was completely crusty and awful, the Napa junk cleaned it right up and the carb was perfect again. Jet blockage and the needle valve are the parts to check first since they are so small and anything that would impede fuel flow will cause major head aches! Good luck man!

Max