Hi all, I've spent some time trying to diagnose this problem and I'm looking for some second opinions. Bike is a freshly rebuilt 1973 Shovelhead chopper with Super E carb, kick only, belt drive, ratchet top, fresh plugs, new coil. I have the carb set per the starting specs on the S&S youtube setup video. I have had it running several times since the rebuild working through heat cycles and a few short rides, now I am trying to dial it in. I pulled the plugs after a ride the other day and noticed the plugs were pretty much white, and that the bike is harder to start, so I think my issue is mixture related but I'm not sure what is going wrong. The acc. pump squirts as it should with throttle and you can see gas in the carb body when it's running and when you kick it over.

What happens is when the bike is running and you give it even just a little throttle (maybe like 3000 rpm ish) and then let off, the idle hangs in that rpm range and takes a while to come back down. It is not affected by pulling in the clutch. I know this problem is typical with intake leaks, and I just tried to identify any leaks using my propane torch but I didn't really hear a change in RPM with that test moving it around the manifold, carb body, etc. I should also say that the o-rings and aircraft style clamps are almost new and in great shape, and just the other day I took the manifold off and re attached it all as sturdy and even as I could, with my carb support bracket.

I have read that the Super E's can sometimes leak through the throttle shaft. I have had this carb opened up last summer and went through it to clean it out. I bought it used but from a guy who said he had it on his evo something or other for just a few weeks then switched carbs and it sat after that. Like I said I tried the propane torch test and found no change in RPM holding it up around the throttle connection on the carb either.

People also say in other threads to check advance weights/springs. I have not checked this since getting the motor back from rebuild, but I know the advance unit and weights/springs are new as well as the points.

Any help or ideas on what to check next would be appreciated, thanks!