so i went for a ride yesterday and got about an hr away from my house, i tried to turn into a parking lot to grab a bite and the bike sounded like a semi with a ENGINE BRAKE on. so i barley made it into the parking lot and found out she was running on one cylinder. this is what I've tested....
i have a power commander 3 with o2 eliminators.
i tried to disconnect the pc3 and replug the factory ECM and it wouldn't start i think due to the fact i still have the o2 elms still on but i can't find my factory ones..
i also tried my brothers coil on my bike still did the same thing.
i checked the crank position sensor and its good.
i check all my plugs and all seems good there also.
i don't have any trouble codes on the bike either.
i tried to check the injectors but the ohms on them are 0 on both
but i did find something just now..... i check my spark to the front head and it has none. the rear has spark. but i replaced mu coil with my brothers working coil and it still ran on the rear cylinder
i also cleaned up all the contacts on the PC3 and threw a lil die electric grease on them for good measure.. i haven't added anything to the bike in about a year and have never had a problem with it until now..

 

My 07 EGU goes in Wednesday for the exact same thing. I was 85 miles from home so turned around and ran that whole thing back in second and third gear wide open. Semi's were passing me on hills I was so slow!!!!! Checked the codes and it indicates a O2 or fuel injection circuit failure. Shop thinks a short.

 

Don't the bikes have cylinder deactivation on the rear jug to prevent overheating?

 

Yes the newer bikes have that but mine is a 07 street bob. So I'm not supposed to have this and I think it's only the big touring bikes

 

aaah CARBS...

 

You didn't say anything about plug wires. Did you trade those out?

 

No carb on an 07, Throttle body with fuel injection.

It was my belief that the 07 FXDB had the rear cylinder cut out, but the OP was saying it was the front cylinder not firing.
I would check spark plug wires and plugs next.

 

does that bike have the one piece coil? with the four wire connector

 

hope I don't sound out of the loop.....but have you checked compression in the bad cylinder....I just recently had a valve spring break on my road glide causing a tow home, and a current wait for some parts...

 

having no spark in a cylinder has nothing to due with a compression check.