Common , it's the way the intake system works side draft instead of down like a car and one cylinder pulling an intake draft , theres alway a bit of valve overlap to on that stroke too . Not a lot that can be done with the E and that , I do on some bikes put a 1" spacer between the manifold & carb that does perk performance but sticks the carb out like old Super B and most don't like that .

 

I have that spacer on my setup on the Evo. I didn't really notice the extra width as I have a 6 gallon tank.
Even with the spacer I get a little back spitting-- overlap from the Woods W6 cam...

 

The accelerator pump diaphrams get weak with 10% ethanol...The diaphram will break down and spray a smaller amount of fuel into the carb throat...I replace mine every 3-years along with all o-rings....Also consider going to a .031 Intermediate Jet....Just some ideas from one who has been there....

 

You at least know why some guys just can't get their head around the overlap thing , they expect it to be just like fuel injection . Nature of our beast .

 

My last super E had a rich condition that I couldnt get rid of....new carb (same) and its been running great. I sold the old one for parts on ebay but got damn near what a new one cost, within a hundred bucks anyway.

 

Overlap is OK at RPM in a carbed engine when the air is flowing....It isn't good at idle or in stop/go traffic!!!

 

I had an issue 2-years ago where the nozzle loosened up (the brass fitting the main jet threads into) and dumped way too much fuel into the carb throat...I found the problem by removing the air filter cover and watching the fuel into the carb throat...The tricky part was it looked like it was coming from the accelerator pump nozzle....Live and learn!!

 

You have just provided the clue. If it runs better with the enrichener on it's too lean, and if it's too lean on the slow jet no amount of accel pump adjustment will make it right.

For a stock bike the .0295 slow jet should be fine if not a little too big. I would start with a .72 on the main jet or around that but no bigger to start with. If you have an .0295 in it now go up to .031 and run it.

You gotta read those plugs to know for sure when your about right. Browny/tan doesn't happen with todays fuel, but if you can get them to look medium grey your pretty right.

These carbs are dead simple but you have to adjust by the book and don't move to the next area until you have the first one right.

Strip it and check for clogs/debris and blow out the orifices with clean air. There is an orifice that you aren't suppose to blow clean but I can't recall which one--it's in the S&S book though.

Keep us posted....

 

Remember..The main Jet circuit turns on after 1/2-throttle open...And that is determined by airflow by a small hole called a bleed circuit...You don't tune the Intermediate Circuit by changing the Main Jet....

 

Been my experience most people tend to have too big a main jet , like bob said it doesn't come into play till 60mph minimum .