OK, here's the thing:
2001 carburated standart, Screaming eagle 2 slip ons, 44k miles. Carb has obviously been drilled, so I think it has been rejetted. The power is, let me call it "not impressive". But it takes around 30 MPG, solo ridden, wich is too much, in my opinion. A/C is new (stock).
Any tips? I think about a mikuni, and maybe a SE ignition. Someone told me that the 00 and 01 models have that problem (the carburated ones).

 

You should get at least 40 mpg with your set-up. I like Mikuni, but the big pumpers are worse on gas than the Keihin.

If your carb has been rejetted, most likely it has too big a main jet. Stock those bikes were fat on top, going up a size (or two as many did) kills performance and gas mileage.

The carb is easiest to work on on the bench. Remove choke cable at the frame mount, disconnect throttle cables and fuel line. Pull vacumn hose CAREFULLY.

A good starting point for idle needle setting is 1 1/4-1 1/2 turns out. On an eight year old bike, I recommend unscrewing the idle mix screw all the way and take out. Check to make sure it is not blunted, clean threads with WD40. Give a shot of WD doen the hole and GENTLY bottom the needle. Turn out to starting position.

Remove top of carb. Note how diaphragm and spring are installed. Check needle. It it is aftermarket it will have grooves and a clip. Clip should probably be in 2nd groove from bottom. If no grooves, check for a 3MM washer under the needle. Shouldn't be more than one with your setup.

Drop float bowl. Make sure main jet is tight in holder. Check size of main jet. I like a 170-75 for a set-up like yours. One famous tuner says go as low as 165 with slip-ons and an air cleaner. You probably have 2 or three extra steps in your main jet.

Check your slow jet. If your bike is HDI (France) it may have some screwball jet. You should be good if you have a 42 or a 45. Bigger or smaller it will not be right. I think it must be for emmissions testing but Harley likes 'em lean as a snake at the bottom and fat on top.

Start bike and warm by RIDING. When engine is at operating temp adjust idle to approx. 1000 rpm (a little faster is better than a little slower). Slowly turn idle mixture rich a 1/2 turn and back to start. Turn lean a 1/2 turn. Which direction did it seem to run better in? Tune in that direction. NOTE: It may run best right around the starting position of 1 1/4 to 1 1/2 turns.

MPG varies a lot with riding style, but I don't think you will get less than 40 MPG with this method.

 

Thank you so much for taking the time to type all this. Very much apreciated. I'll print your answer out and go to work
Thanks again
Jean-Luc

 

If you get into it and have questions PM me. I'm actually a fan of the Keihins because I hated their Bendix and Tillotson predecessors.

 

Trying to figure Your post out, hard to follow Ur thoughts or meaning here.

First,U say Ur at 44mpg's, then had or have carb work, then state, no power.

But what does ( it takes around 30MPG, solo) mean???

Of the couple carbs bikes I ride with both say they get 45-50MPG. and have
pipes, A/C and cams.

 

I didn't write 44 MPG, I wrote 44 K, means the bike has 44 thousand miles.