Hi all,
This is my first time posting a thread here. It seems like a great platform to help me in my hunt for a fix, so thank you to the people that take the time to read and comment.

Ive recently purchased a 2011 fatbob with a 110 cube upgrade on it.
It was a project and is very rough and not looked after.

it wouldn’t run upon inspection as seller told me the fuel pump wasn’t working.
This was correct, so I put a new fuel pump, regulator and filter in the tank.

Now I can start it but the problem is that when start it it fires up as normal but after about 3 seconds it drops the front cylinder and runs on the rear only.
Then proceeds to flip flop between running on 2 cylinders for a second or two every now and then to running mostly on the rear cylinder only.

I have checked the plugs, leads and coil. If I pull the front lead off the coil while engine is idling there is no change to the way it runs. If I pull the rear one off then the bike stops.

I’ve used an in-line spark tester. On the rear cylinder the light flashes nice and bright, but in the front cylinder it is flashing but it’s really weak.

I pulled code P1352 front ignition coil driver high/shorted.

It seems to me the coil is being told to stop spark for some reason.
This is where I’m a bit stuck.
I’m handy with a multi meter, but don’t have any of Harley testing equipment.

Has anyone seen this before?

 

Spark plug on front cylinder is wet.

 

 

I have run test 1 with multimeter and I got 1.5v for that but can’t find a short in the wire. I have even run a loop wire from ecu to the coil with no change.
What is odd though is that I ran the same test for the rear cylinder and I get 5v.

 

Compression on front cylinder is 190psi and rear is 185psi, so I think I can rule out a compression problem.
I’ve tried a different (known working) coil and no change.

 

Look at this guy go...talking his way through his issue all by himself lol...can't believe nobody has commented to help the poor guy out.
You said it has a 110 kit on it..
any idea if it's been tuned and with what? Could be an issue with the tune. If you or a friend has a power vision you could see what tune is in it. You won't be able to make any changes unless the p.o. brought a license for it but he doesn't sound like the type that gave a **** about his motorcycle. That's all I got...

 

Did you try swapping front ignition coil with the rear?

 

Thanks for your response Screamin Beagle.
I figured that I might as well keep updating the thread as I went. One thing that I put on there might make sense to someone and then the cogs might start turning.

I don’t know what tune it’s got in it, but what I can say is that I don’t reckon the bloke I got it from did any of the mods to it in his time.
this was at one point a very nice bike with a lot of money spent on it.
He had it for about 5 years and said the only thing he changed was the bars.

 

Dynoking, I have tried that.
the rear that normally runs won’t run and the front cylinder will crank, crank, crank then bang. It ignites and throws a blue flame out the pipe. It doesn’t run though.

What should it do if leads are reversed?

 

may be a burned ecm. Check the voltage going to the coil and make sure there is continuity from the coil to the ecm