Hello,

My son has a 2004 TRX400EX. Practically from new, it has had a warm-up or idle issue, I don't know which. When you start it from cold or hot, you can not use the choke, it will just kill the engine, and you have to keep the throttle reved up very high for several minutes. Then while still keeping the throttle reved up, you have to jump on the bike and take off like crazy and keep the revs up while shifting and riding. Even after riding for a while it stalls out if you let it try to idle.

I don't have a tachometer. The Clymer manual suggests to adjust the idle screw but does not explain beyond just that. I did try turning the idle screw, but the screw wants to spring back to its original position. I traced the cable to the other side of the carb, and there is a knurled metal collar where the cable enters the carb. But I can't get to it to see if I can loosen it. How would I get to this if I need to?

The air cleaner is clean, the gas is fresh, oil is fine, brand new - properly gapped spark plug.

What should I try? Any help would be greatly appreciated. Thank you.

Chip

 

Id start by doing a carb cleaning. Sounds like the pilot jet is plugged shut. Rather than clean the pilot jet...just go to the dealer and get one thats one size bigger(#38 is stock, and #42 is a good choice). Lots of people do this mod, and it starts so much easier, and idles like a champ. The bigger the number the richer it is.
Check out this article on replacing it.
http://www.exriders.com/techarticles/pilotjet.html


Then while the carb is off...work on the idle adjuster. You might have to work some penitrating oil in there, because its probably rusty or coroded.

 

Thanks hondabuster!

I'll try as you say and see what happens.

Thanks for the article explaining exactly what to do - very helpfull for me.

Take care,


Chip