Let's try this again

I recently posted a thread about an engine idle problem and got no response. Could it be that no one has experienced this. HELP PLEASE !!

426 Engine idles great when cold. After warm up, engine idles high, maybe 2500 - 3000. If I drag engine speed to normal idle w/ load it will normal idle until throttle change then goes back to high idle. Opened pilot needle up 1 turn and symptoms some better. My guess is that pilot jet too small & mixture too lean after warm up. Anyone had experience w/ this?

well let me be the first to post something for you. i have a 97 dr435 (dr350 with 435 big bore kit in it). that bike used to do the same thing . on the carburator on that bike i just turned the little knob that would push the throttle open or let off the throttle till the bike ran right.i'm not sure if the 426's have that or not. hell i'm not even sure what that little knob is called but it worked for me!!

I think you are on the right track. Actually, this subject has come up many times before. It does seem to relate back to Pilot jetting (including Fuel Screw adjustment). Try adjusting your fuel screw first and then go to a bigger pilot jet if you get past 2 turns out.

The idle setting might also contribute to this situation as too high of an idle may cause the CDI to adversely alter the ignition during idle based on the programmed map.

Sorry I don't have experience with the 426 specifically. High idle or hanging idle generally indicates a lean condition. Idle that stalls or drops momentarily then comes back up indicates a rich condition. So unscrewing the fuel screw (richening it up) is the correct way to go. How many turns out are you now? Can you go further out? Did it always run like this or did this symptom appear recently? If recently, it may be that colder weather is causing the lean condition because the air is denser. It is common for us to adjust the fuel screw in the winter. Dirty fuel passages or partially clogged jets can also cause a lean condition.

Thanks for all replys. Have a 425 cc Big Bear quad that experienced the same thing. Open the pilot screw and condition improved. The WR426 did it right out of the box. Idle perfectly when cold. After five minutes, it goes to high idle. The air screw is set @ 3.25 turns. Clearly, the next step is to change to richer pilot jet. I have a Thunder Alley pipe due to arrive any day and bought the recommended 168 MJ for the pipe. No change recommended for pilot. Logic would say, one PJ richer which is #45 to address this condition. Any thoughts about that ??

I'll hang up & listen. Thanks

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now