Running like crap.

[JForestZ34]

I went riding a couple of weeks ago with a couple of my buddies. My one buddy doesn't have a quad and wanted to ride so I let hime ride my 400ex. Anyway we go riding for a couple of hrs. I'm riding my yfz450 and he's riding the 400. So after a litttle bit of riding the 400ex starts to backfire and run like crap. Well then we find out that it ran out of gas,, HA I forgot to fill it up with gas the last time I rode it. So we switch the fuel thing to reserve and start our way back, and it'still running like crap. There were times that he would be riding and it would just stop running. If we just sat for alittle bit and then tried to start it, she would fire right up, but when it shut off and we tried to start it, it wouldn't do anything, but crank. We filled it up with gas back at the house and still it would run like crap... So I went out today and got a new spark plug and threw it in and it ran a little better but still was having problems. Now the gas I put in was fresh so I don't think that is the problem. When the bike is cool is runs just fine but it seems as it gets hotter that's when it starts to stumble and fall on it's face. DO you think it's running lean. But I never had any problem with the bike until now. I have no idea what the hell could have happened? I checked the plug and it shows alittle sign of a lean condition but it was the same way before this happened. The bike never overheated or anything so I have no idea what the problem is. If anyone has any ideas I would really appriciate it..

James

[blasterandy]

Mine started doin the same thing. On mine the spark plug wire is jiggling loose and almost coming off. So check and see if that is it.

[Sparky_20]

its possible that your carb or feul petcock is gummed up. Did you check your air filter to see if its clogged?

[JForestZ34]

I just cleaned the filter. I was thinking that could have been it but I cleaned it and it's still doing the same thing. I'm starting to think that it could be the pet cock on the gas tank. Could be that when the gas got as low as it did it could have had some junk in it and could be covering the petcock. How would I check that will tall the gas have in the tank.. I guess I could take the fuel tube off going to the carb and drain in into a gas can.


James

[300exOH]

Sounds like you got some dirt in the carb. It happened to my wifes 250ex a couple of weeks ago. I did the same thing...ran it out of gas so I put it on reserve and it started doing the same thing as you described. It would idle but wouldn't rev. Take your main and pilot jets out and clean them with carb cleaner. I even had to take a sewing needle to push some small particles out of the jets that the cleaner wouldn't get. Just make sure you hold the jets up to the light and look through the hole to make sure they are clean before reinstalling.

[86 Quad R]

also check and see if the gas cap is venting properly.

[brandon86]

Check for fire after it gets hot and dies. Maybe coil or other electrical part not makeing contact after it expands.