[Weldangrind]

Waynev, that's almost exactly what I was struggling with. It has been my understanding that the main jet controls the mixture at tip-in, but now I'm inclined to question that.

The main jet is (as we're all aware) directly below the slider needle. As soon as the throttle is opened, the needle is pulled up from the jet, uncovering the orifice. It seems to me that if the orifice is a larger diameter than stock, more fuel would flow upon opening the throttle (I think we can all agree so far). The thing that hadn't occurred to me is that since the idle speed screw simply lifts the slider, the main jet is uncovered even at idle.

To support this, I made no other mods and the quad fired right up. It still has a bit of a 'hunting' idle upon blipping the throttle, but I think that's something else. Maybe I just crutched it, I dunno.

I noticed a mis-match between the intake tube insulator and the new Mikuni, inside and out. A person would need to hog out the ID of the insulator to get maximum benefit from the new carb. The o-ring on the Mikuni isn't completely covered by the outside of the insulator either. The easiest fix would be an insulator that is designed for a 30mm Mikuni or Keihin round slider carb.

I'm not convinced that the stock insulator isn't creating a vaccuum leak. Anybody else have idle trouble?

Maybe a bigger idle jet will solve the idle issue; I'll see about picking one up today. The symptom remains that when you blip the throttle, it takes 2-3 seconds to come back to idle. That's despite re-routing the throttle cable to a more relaxed radius. BTW, it had the same symptom with the smaller carb, but it was worse.

Pete, to be clear, I used a #59 bit, which is 0.041".

Cheers!