I've been trying to chase down a very irritating problem over tha past couple of days. When I slowly roll on the throttle, my bike splutters and near dies if I don't give the throttle a good twist. The bike starts and idles fine. When idling if I give the throttle a good twist, the bike revs up easy with a couple of occasional pops through the carb. That can been dialed out. What is irritating the hell out of me is the stumbling in transition. I suspected an intake leak , but wouldn't that affect every aspect of carb operation? Any ideas?

Thanks

45 pilot jet, 165 main.

 

When I jetted my wifes Sporty it had bigger jets than that. Try 47-50 and 180-190.

 

If its a roll-on problem then you are lean during the 1/4 to 3/4 throttle positions. You probably have a surgeing problem as well. This could be caused by a leaky intake but usually your idle would suffer more then mid-range.
Try raising your needle position one - two notches (move the clip toward the tip) and see if that helps.

Edit...I know these carbs just not as they apply to HDs. Anyway I was checking out the CV carb thread, a very good informational thread by the way, and realized that stocke HD cv carbs dont have adjustable jet needles. I know, freakin DUH!!! You may need to purchase the Dynajet kit which comes with an adjustable needle otherwise a washer spacer under the head of the needle works but you can only go .030" or so.
I just thaught of one other possible cause of your problem, it could be a tear in the diaphragm at the top of the carb. The diaphragm is attached to the slide and jet needle so you will have to remove it anyway.

 

That was my thought as well. I've had the needle shimmed for a few years now. Up until a couple of days ago everything was fine, bike ran great. It's likely one of those problems that is very simple but not easily seen.

The carb is off the bike now so the I'll check the intake seals and the diaphragm more closely. It could be I picked up a tank of sh!tty gas as well. I'll get it eventually.

Thanks for the response.

 

Put an S&S E on it and enjoy it.