OK, so working on this for a guy on my race team.

I tuned it up beautiful back over the winter on a fresh build. Stock, with an HMF Comp slip-on, UNI filter and stage 1 cam. Tuned it up for lid on cause it was cold and he planned to add an EHS lid when it got hot.

Somewhere it flew apart like a $2 watch. I wont go into the details.


Anyways, he changed the jetting to a 180 main and left the 42 pilot we installed. (Pro X Jets) I worked on it and got the thing going, but realized it idled best with the pilot closed? I mean all the way. So I assumed it was the adjustable needle he put in. So I moved the clip back to center and put it back, adjusted the sync and bam... cranking awesome, running awesome... but just sitting idling it would flux a few hundred RPM and also sounded a little trashy on decel. Not backfiring just junky.

I tweaked on the pilot and again found it ran best with the pilot screw closed? I go ride it and it does really well, but after a long decel down a hill to test for backfire, just as I go to turn around it dies and won't start back.

It was like it was running out of fuel or not getting spark and then it just fired up. Idle was slow at first and then picked up. So I went and got a screwdriver and a spark plug to stick in my pocket and off I went. After like 4 tries it dies again. So being a wise guy I pop right off and open the drain... bowl has gas. Pull the plug wire and put a plug in... yep I got spark. Not so wise as I thought...

I put the stock needle back thinking it must be a slide/needle thing and the long decels suck it down where it really only has supply from the pilot, which is closed so it dies.

Well now, with the stock needle it will idle best at about 3/4 turn from closed. But this is with the idle adjustment wide open... and it barely idles maybe 1400 RPM?


I have not ridden it yet to see if it will still die, but I got a feeling this still aint right and it is also not going to perform as well on the throttle. I will find out tomorrow evening.


I am really at a loss though? What could this be?