Stumble off idle /1100E -- pilot air jet?

[dpep]

I am taking my 1100E back to stock airbox and carb settings with stock exhaust. I am having someone do this for me but talking with him at each step. It used to have pods with a 138 main. Now has airbox and the 110 main from the Dyna kit (stock is 112.5).

He says that it is pulling strong except that just coming off idle, under load, it hesitates. It doesn't happen if the bike is in neutral and you are just revving the engine. This is all after the engine is warm. He replaced the stock 180 pilot air jet with a 160 from the kit and set the floats higher which he says made an improvement. But he thinks we need to go to 120 pilot air jets to completely fix the problem.

That seems like a big change to me with everything else at or near stock setting. Plus no one stocks the pilot jets and it will take two weeks to order them in. I would hate to be two weeks later with the problem not resolved or a new one created. Is there something else we should look at first?

I'm just curious what somebody else's top-of-the-head opinion would be.

[Dave8338]

Don, have him bump the jet needles up 1/2 notch and see if that helps the situation.

[mike-s]

I think Dave's on the money. Remember you can meter the fuel and the air, messing with the jet size itself can only do so much if the needles themselves are wound too far in. Get him to take the caps of the pilot screw (if in the US) and take note of how far each one has to be screwed in to bottom out, and compare that to 2.5 turns out which is a pretty reasonable starting point for fixing up the idle settingsm.

[49er]

Don, When the bike was originally tuned for the pipe and pods, it probably had the pilot jet size increased. When you return the bike to stock specs with airbox and exhaust, you really need to go back to stock pilots as well.

Does the bike drastically hesitate off idle and remain that way for a short period under throttle? If so its a lean condition. If it is a minor hesitation but takes a while to improve under throttle, then it will be a rich condition. I suspect the latter, as your mechanic will have made the idle circuit richer by fitting a smaller air jet (160). The other thing that can seriously affect the transition from the idle to needle circuit is the float levels. If they are too high, you will get a flat response just off idle.

As others have mentioned, you may have the needles in the wrong position as well.