I would assume that the previous owner had installed aftermarket pipes, K&N high flow air cleaner, and installed a Dynojet jet kit in the carb. Then kept the pipes when he sold it. Look up the instructions for the Dynojet kit would be a good place to start.

 

Also what 2 inch Drag pipes did you put on. Maybe it would help if you installed torque cones in the head pipes. I have had 2 Sportster bikes and I ran 2 inch Khrome Werks Drags ( they have anti-reversion cones built into them)

 

Snappy low-end and straight pipes don't mix.

It's called drag pipe sag, and you can't tune it out by tuning the carb. You want snappy and responsive low-end, you need a 2-1 pipe with a baffle. Torque cones are snake oil. Best you can do with drag pipes is a bolt/screw in the end of the pipe.

 

That video was the absolutely best one I have ever seen to explain how the exhaust pulses actually affect the bike running. I have a hard time explaining things at times (most of the time lol) Thanx for putting that up!

 

I don't know about torque cones, but I know that torque inserts near the end of the pipes are fantastic. Huge difference once you get the exhaust velocity sorted out. I have them on 2 of my bikes because of the type of exhaust I run. Check these out:

Thunder Torque Inserts - Exhaust - Sportster Parts

DK Custom Products for Harley-Davidson Tank Lifts Coil Relocation Ignition Relocation HiFlow 587 Air Cleaners Custom Foot pegs Tour-Pak relocation rigid struts Bear Trap brass knuckles bmx XiED Solo Seat Systems Pans ChopperShox K&N filters Thunder Torque Inserts ViED

www.dkcustomproducts.com

 

I have a similar problem, got an 883 k&n filter, and straight pipes, runs lean on the highway but foules plugs at idle. Did you ever figured it out?

 

Probably bad tuning, probably because they're trying to tune for straight pipes on an engine that doesn't have the cam and flow to justify the straight pipes at the diameter they're at. AFR and pilot jet should only be for tuning idle and just off-idle. Tune full throttle by main jet, then tune mid throttle by needle size. Remember, carb tuning is by throttle position, not RPM and the pilot and AFR adjustment is for 0 to about 1/8 throttle, the mid-throttle is dictated by the combination of main jet and needle, and the last 1/4 throttle is dictated entirely by main jet.

Most straight pipes are too large a diameter to work well with a stock engine.

 

Check that the enrichment device (choke) is closing all the way. That will make it rich at idle no matter what you do to adjustment. I have found this on several of the CV40 carbs used back then.

 

I second the enrichment circuit, the needle can leak fuel and cause a rich condition across the rpm band. Remove the cable and needle and inspect the sealing tip, if the black Viton appears to have a circular dent the needle is most likely leaking excess fuel into the carb venturi.

 

I second the enrichment circuit, the needle can leak fuel and cause a rich condition across the rpm band. Remove the cable and needle and inspect the sealing tip, if the black Viton appears to have a circular dent the needle is most likely leaking excess fuel into the carb venturi.

I checked the whole carb. Everything seems in order, thing is it was always lean with a 45-170 wich is curious. Ill change to performance pipes and see