Carb adjustment help...

I just got my first HD (2003 Sportster 1200) and am getting ready to do a little work. Bike runs fine, but had a caugh at speed (not on decel or accel) and had a backfire thru the carb at idle. This is what I know and what I've done:

Dealer put on a SE aircleaner (full flow), new pipes (Cycle Shack Slash Cut 1 3/4 M Pipes http://www.pipecity.com/Products/Pro...roductID/66427). The carb had been adjusted as the mix screw was not plugged.
Spark plugs were tan prior to doing any work.
Idle was set around 1400 rpm.

I removed the carb and cleaned it and reinstalled = little change, idles rough at 1000 rpm. Mix screw seems to have no affect.
I replaced the slow jet (42) with a (45) from the dealer = seems rich and possibly running a bit hot dles rough at 1000 rpm. Mix screw seems to have no affect.

I have looked for an exhaust leak and intake leak but have not found any. I replaced the vacuum lines as they seemed suspect.

I have read just about every forum post and have tried just about everything that I've found. I'm unsure if the dealership did a "stage 1" upgrade without doing the jets since I don't know if the pipes are "stage 1".

I took the bike out today... the caugh is gone but now it's definately running rich and the idle seems a bit choppy. I have a little hesitation in the lower RPM range but definitely drivable. Plugs are light gray with a dark ring at the base of the threads. I'm adjusted about 3 turns out on the air idle screw but it still seems to have no affect.

Any ideas to adjust? Thanks!

1400 rpm is a little high - try setting it to 950/1000 rpm and redo the idle mixture - also put the 42 jet back in and go from there. main jet should be no larger than 180 - after you get that done try redailing it in - And if that don't work check with ART - he the sporty man on the forum and he may be able to help out with a few more ideas.

Thanks for the idea! I had thought that I should go back to the 42 and try again... I get a little change when adjusting the mix screw, and I'm now about 2 1/2 turns out. I don't have the stumble or cough that I had when I got the bike a week or so ago. No more backfires.

I don't have the time to take it out for a real test drive, but I have a set of fresh plugs installed to run in the morning to see how it's doing. I didn't notice any hesitation in the low RPM's, but only a real test drive will tell.

I'm also going to run some seafoam through the rest of the tank to clean the rest of the crap out of the carb. I think I'm really just fighting a dirty fuel system now, since putting the old jet back in didn't cause the issue I had to begin with.

On another note... has anyone ever got some crap under the glass of their tach? If so, how did you get it out???

Thanks!

I took the bike out this weekend and she's running pretty good. I think I have a little bit of a bog when shifting, but nothing bad. It might just be the nature of the beast that I'm not used to yet.

I went to the local bike shop (not HD dealer) and the guys there said it seemed like it was running right, even with the upgraded A/C and Exhaust and running 42 and 170 jets!

Thanks for the help!