2003 sportster wont start or run right when it is warmed up

Hey dude, did you have trying on intake pipe leak ...spray any carb cleaner on the manifold intake....any change would be an air leak....
Voila.Thkx.

There is not enough information. Start with the simple first by looking for vacume leaks John has already done a great job describing that process. Once you can establish the problem is not mechanical then start looking at electronics and wiring. In the past I found a lot of interesting problems were solved by removing grounds, cleaning the surfaces of corrosion and remounting the grounds and using a heavy grease on top of that connection. If the connection gets hot use anti.seize grease. Use any grease sparingly avoid making a mess later due to too much grease dripping hot at speed.

Well, what is it a 2000 or a 2003, obviously not a 1200S so no codes available. When it runs cold is that with or without the enrichment circuit (choke) active?? Is the float level set right? Is the carb diaphragm okay or has it got a hole in it?? It is running very lean when hot as evidenced by the popping on deceleration. Does it run better when hot with the enricher somewhat activated?? What if you spray some fuel into the intake when it is hot and not running well??? Check for downstream from the carb induction system air leaks when hot by spraying, very carefully, WD40 or such all over the induction system seals etc. and watch for an increase in rpm etc. There is no cam position sensor on this bike but 2003 has an ignition module which does cam position sensor functions. Is the timing correct, not likely the problem but ..... If there is no intake leak, the carb is all okay and the float level which is critical is correct, check out the VOES (vacuum operated electrical switch) which switches between two ignition timing settings depending on engine running conditions. Of course motorcycle spark plugs are also critical and a good looking plug may not be good in fact and may break down when hot and under combustion pressure so be sure the plugs are good (just having a spark apparent under no compression pressure is not a good or complete indication of a good plug). It is more likely an enleanment problem than a plug problem though from the symptoms. Also assuming the air filter is good and not plugged which would greatly contribute to/exacerbate problems.


John

Sounds like the cam position sensor.

Best way to approach troublesome fuel problems I start by ordering a new carb got one on line for mine $60.00 brand new came with 3sets of jets jeted the new carb on it put it on and slamdunk before with my old carb had problems with starting did not want to run smooth when it got warmed up stalled would load up put the carb on there and happy happy spent a lot of time on it and it was like night and day

Check exhausts if black or sooty exit then sounds like mix is too rich. That being the case, problem wont be air leaks as that would cause too lean a mix.

I'd say put that fuel injected piece of **** in the garbage, and go buy a used 1982 on eBay :)

ask me about carburators bro

Carb need a cleaning

Jets might need adjusting , to much fuel, to much air not enough of either. Float bowl is stuck, air leak . Check the plug

When they rebuilt the engine was your carb rejetted it should have been done also in the exhaust are they using power cones if so use should not be using baffles with them one or the other you take your chances with no baffles on tickets check the carb jetting first

Just in case you haven't had your valves adjusted in a while that could give the symptoms you describe.
Another thing to check is your fuel jets, drop the bowl out and unscrew the jets, blow them out with compressed air.
If the bike runs okay with the choke on, but does not run right once the choke is off, your jets are dirty/partially plugged.
You should also check that your plug wires are in good condition, and have not developed areas where the insulation is worn, allowing the spark to arc to whatever is closest.
If all else fails run a compression check on the bike, you could have a carbon buildup, or a valve seat/valve getting a little iffy.
You may also want to check that the carb fasteners are properly torqued down, and that the carb gasket is good.
I ride a 65 Pan(ex Kansas city police bike, standard transmission), and a 53 Indian Chief(also a standard), the pan once had a problem with corrosion under the bolt that holds the battery box ground wire to the frame, that can cause all sorts of problems, from not keeping the battery charged to not getting enough juice to the plugs, to (very) hard starts(the 65 was the first pan with an electric starter), and cutting out at speed, backfiring, not idling, it was like El Diablo was messing with me.
I went to the tool box instead of a priest, but a priest with a tool box would have been cool.
The Indian was bought as a not running, Honda shop "mechanic" says can't fix it, bargain back in 71, it had a tank full of water and rust, cleaned the tank and everything including rebuilding the carb, and shazam! First kick, and she's ready to go for a ride.
Check all the stuff John #1 told you(he's real good on this later model stuff), if it doesn't help, check those valves (and compression).
Good Luck and remember, car drivers can't see you, and if they could they'd try to kill you.
One last thing, 70% of the stopping power of your bike is on the front wheel, I don't know how advanced of a rider you are, but practice braking HARD with your front brake.
An easy way to get used to the front wheel being locked up, is on a dirt road at low speed roll on the throttle (barely) and lock the front brake, sliding the tire, this will give you the confidence you need when you have to make an emergency stop.
Also, learn about counter steering(if you don't already know about it). Over 12 miles per hour, if you want to go left gently nudge your handlebars to the right, it'll bank to the left like an F-14.
I'm sure you know all this, but hey, on the outside chance you don't, take it from an old racer, it works, and it can save your life, and I figure you are worth keeping around a while.
All the best, and good luck!
John (Sparky)

Have you changed the Ex. pipes, if you have it can cause these problems, needs a richer setting for carb.
Could be this simple.

This may or may not be the same as mine, but I have an 03 XLH 883 and it comes to find out that the Ignition location and componeets is a lot different in most models. Finding parts and information has been a travesty at best. First thing is, everyone uses a different name for the same thing. On my model as it turns out, the Crank/ Cam Positioning Sensor is the same as the Ignition Module. On other Bikes it is mounted elsewhere. From all the reading and searching I have done, each of the symptoms are slightly different, as well as components mounted in different locations. unfortunaly there is alot of confusion on this topic even though it seems like it is fairly common. the new module was quite difficult to locate and replace. PLus the directions/ wiring are quite vague and cloudy. The first Module has 5 wires but the new one only has 2. It is not clear which wire goes to which side of the coil, so be careful when you hook it up...

I'm sorry, I can't help because I own a Suzuki. Oh, wait...that would fix it!!