I swapped out the plugs with new ones as soon as it started sputtering. I didn't check the wires or the coil though. I know they're aftermarket for sure. How do I even check the wires?! The thing is, it idles fine and with the choke engaged it seems to behave normally. If it was spark, wouldn't that affect the idle?

Today I swapped out the carb with a known working one. Still the same issue occurring. I pulled apart my old carb while it was off too. Jets are still clean, I didn't go much further than that though. I guess I'm going to have to install that new manifold and seals. I really don't want to though

 

Change out your MAP sensor. I had a issue with my carb or so i thought and i couldn't get it to run right no matter what i did. then i changed my MAP sensor and it runs perfect again.
https://www.hdforums.com/forum/carbu...confusion.html

 

Mate I'm going to suggest something but I'm not a Sportster guy , listen to these guys first .
To me it sounds like the timing plate is on the fritz , dude I don't even know if the sportsters have that system but if a bike came in with those symptoms , the first thing I'd do after carb management is swap out the timing plate if it had one or whatever managed the timing..

 

I "think" I read all your posts completely so here's the deal - you have all the classic symptoms of an intake leak. Actually finding a leak with spray or propane is a 50/50 at best and often misleading regardless of the findings. The 48 is way big for a Sporty, another indication of an intake leak being masked by too big a slow jet.

The choke cable and starter valve absolutely must be operating correctly. Without a VOES you ignition will not advance correctly until the rpms are above 2500 unless it has points or some other puckup that uses a flyweight system. So look behind the cover and verify what you have there. If it's stock or aftermarket electronic ignition you need to put a voes back on it.

I'm not a Sportster guy, but know these carburetors very well. Replace the dinged up manifold, use new o-rings at the heads and a new carb grommet, verify your ignition type. We'll go from there.

 

If the MAP Sensor is the one that mounts to the manifold then I don't even have one, lol. Ill take a look later today but I'm pretty sure its not there. I think even my manifold has no slots for it or anything

I appreciate all the information you guys are giving me.
The bike does have an aftermarket ignition. Its an Ultima with dip switches. I don't know if thats a good one or not. It runs a self test upon keying the bike to "on", which it did and passed. What the self test actually does, I have no clue.

As far as the carb goes, I bought a brand new choke cable and the relocation plate that sits on the carb top. This is the only place it would fit, HOWEVER the choke elbow smashes against the cylinder head. Its brand new and the rubber around the elbow has already torn exposing some metal. Choke seems to work fine though.
I still have the spare carb on because I'm too lazy to take it off, but that one has a 45 pilot/165 main still showing the same symptoms. I have a 46 pilot lying around somewhere that I'll put into the old carb.

I'll start on the manifold today. I know its only 4 bolts but they seem like such a pain to get to. I have to use an Allen cut in half and turn that Allen with a ¼ wrench. Fun stuff, haha. I don't know how I'm going to torque the damn thing though.

Thanks again guys for all the expert advice

 

Yeah they're a pain but don't worry about a torque spec. When the flange gets to the head, the bolt will stop. Just give it a little more umph, just a little. Be sure to pull them down even with each flange equal distance from the head, a 1/4 turn at a time, alternating from front to rear WITH the carb and air cleaner back plate mounted to the heads. That procedure is very important (as well as time consuming and tedious)

With that ignition, you absolutely need a voes if you want any decent fuel mileage and good acceleration from low rpms. Don't worry about the jets for now either. 45 is good, 165 a bit small, but will suffice till you get other things sorted out.

 

Update

Changed out the manifold today. New seals were put in however the old ones looked pretty good. Took me about an hour or two total. The carb was mounted via the bracket while the manifold was just a hair loose from finger tight. Then switching around from bolt to bolt ¼ to ½ turn at a time. Fired her up and same problem.

I guess that leaves timing. Which I've never done but from the videos I've seen it looks fairly straight forward. And from there, I have no clue?! I guess to the shop, haha

I'm just baffled that it was running smoothly and out of nowhere this problem occurs. I know that on the ultima ignition there is a dipswitch for VOES. I think its currently set to off. Is it supposed to be on even thought my VOES isn't setup? Or am I to install VOES? I'm just shooting in the dark here, haha

 

Sorry all that didn't take care of it, but you have eliminated that area or possibility. It just dawned on me - if the Ultima ignition was installed as a kit, the coil that comes with them is total junk. I've heard more bad reports about them than I can recall, including I had one myself that lasted 200 miles until it got wet, then died. A bad coil can also give similar symptoms to what you have. Check out the coil, whether it has 2 small posts or 3. If you have a stock coil, try it. The Ultima ignition itself is very reliable with an outstanding reputation.

 

Ok, ill ohm it out tomorrow. It has the 3 posts. I hate where its located too. It makes it damn near impossible to mount the choke. I thinking of getting a different carb just so I can have a choke thats free of obstruction! Haha

 

Keep in mind, if a coil ohms bad it's bad. But just because a coil ohms good doesn't mean it is good. Learned that the hard way.... and those coils that came in the "kit" have a horrible reputation with more guys than me.

If you try a stock type coil, connect the pink wire from the module to the negative post on the coil and insulate the blue wire. White wire is (+) feed from switch and to the module.