Hi, some may remember me. I got the same problem. I hope someone out there has had the same problem and can tell me what to do. I'd be embarrassed to take to the shop, I'm 52 and have worked on motorcycles all my life. Harley's only two years but I've got lot of experience. This has me stumped!
I have a 2006 NightTrain twin cam 88B, carburated. Bought it brand new. About a year ago I put Vance and Hines Big Radius pipes on and re-jetted the carburator a little richer. The machine ran wonderfully for about 8 months and suddenly it started to want to hic-up and stall after being hot and easing off from a stop. It has died in the intersection a couple times. It still runs great until it becomes operating-hot and pulling off from an idle. I can run for hours and if I don't stop, I'd never know that anything was wrong. The idle does change when it gets hot. When it's warming up and I ride it around, it has a nice Harley lope at idle, but when it gets hot it "Puts"! put-put-put. I tend to think it's sucking air somewhere causing it to lean out, but WHY just when it's hot?
OK, so far I've changed my gas station I go to, (I do burn premium) spark plugs, intake manifold gaskets, intake manifold MAP sensor, and totally went through the carburetor 3 times cleaning it totally, and have replaced the low-speed jet two sizes richer. Again, the bike runs great and idles great until it's hot, and pulling off from an idle. I have pulled the plugs and it's reading a little lean. Again I'd say it's pulling air from somewhere. If this is the case though, why doesn't it act up during cruising speed. Question, does this bike have any centrifugal spark advance? I'm wondering if it get an advance signal and doesn't return retarding advance while idling.
I'm stumped!
The only other thing I can think of is to buy a new carburetor or the little electronic box (the brain for setting the timing) and hope for the best.
Help!
PS I also have squirted carb cleaner around the intake manifolds and have no idle change.

 

You describe the exact problem my son had with his 2004 XL1200C last year about this time. Took two trips to the dealer to fix it. First time they thought the jetting in the carb was incorrect. Second time they replaced the crank position sensor. Not sure I understand how it's all connected but it fixed his problem.

 

Thank you for the information. Maybe I WILL look into the crank position sensor.
Thanks again for responding.