I put cold in parenthesis because it's been 600,000 degrees here the last few weeks. So I don't mean temperature cold, I mean "not run in a bunch of hours" cold.

In the last 2 weeks, my 07 deuce has started to either "cough" through the intake and almost die, or straight up backfire (intake) and die, only on first startup of the morning or after sitting all day at work. It will turn over a few times, fire for like 2 cycles, then backfire and die. Or cough and die down, then idle out and run fine. Then starts back up and runs fine.

bike has:
fuel injection/96" motor
12.5k miles
2700 on plugs and fluids (probably change plugs to eliminate that possibility)
Rineharts and Race Fueler (been on it since I bought it last year with 5.5k on it)
only thing done to the bike this season, went to a 180 rear from a 160 (coincidentally that's about when this issue started, but don't see how it could be related)
no check engine light
bike runs fine otherwise

Dealer wants me to set up an appt so they can plug in and try and find the issue. They suggested possible crank sensor. How much and how easy is a crank sensor to replace? I'm not gonna pay them $100/hour to throw sensors at it if I can do it myself. Anyone have any suggestions? Thanks!

 

With no check engine light...I would check for a vacuum leak....as the engine warms up the leak closes somewhat ...causing the motor to run better.

 

so intake gaskets? I did have the air cleaner off this winter when I did the apes and cables, but the throttle body never came off. There are no vacuum hoses, are there? Just those two hoses that come out of the air cleaner plate and go into the heads, right?

 

Another thing to check is a pinhole in the gas line inside the tank..

Just did mine two weeks ago while on a riding vacation 500 miles away from home . My 07 also started starting harder, it'd turn over 3-4 times before firing.. never done that till then.

Another issue will be missing out after a certain number of miles on the bike ridden after filling up..
Mine would run perfect till about 110 miles after filling the tank.. Then start missing.

The wrench said he's thinking all this Ethanol gas is eating the hoses inside the tank... 3-4 yrs is normal time when U need them change..

 

my guess with this limited info, is a bad map sensor in the intake manifold, but spray carb or brake clean around the intake gaskets to see if it wants to die or rev way up