intermittent spark front cylinder

[wolf_59]

Just helped a friend do a 103 big bore 48 cams street ported heads on his 07 dyna wideglide fired right up for heat cycles no problem, about 1 1/2 minutes into the 2nd heat cycle it started running rough and smelled of raw fuel, checked it today same thing front cylinder and exhaust was cold hooked up automotive timing light front cylinder has very erratic spark and then no spark for awhile then erratic spark, compression is good both cylinders 165# here at 6000' elevation should be 204-205 sea level
So far I have pulled and re-installed the plug wires and swapped plugs front to rear same results once it comes out of warm-up it starts dropping the spark to the front cylinder
Practically a new bike 6500 miles on it
Point me in a direction as to what it might be
TIA wolf

[PC_Hater]

When my bike did that it was the coil breaking down as it warmed up.

Check the wiring to the coil and the oxygen sensors in the exhaust.
Might be the oxygen sensor breaking down.
Those are the easy things I can think of.

Not many miles but 12 years, time takes its' toll.

[Sycho01]

I would check every electrical connector that was unplugged and the re pluged upon asssembly. Don't over look the fact that a pin inside a connector can be bent or pushed back and is not making good contact after heating up. Wiggle test the wires before and after the connectors.
I am not sure about the '07s but I had a  '09 Softail that had ion sensing spark plugs. No compression would= no spark. I found this out on a cam change when I mis adjusted a pushrod.
Try to borrow a coil for a test run.
Hope this helps some.

[PoorUB]

Engine temp sensor?

What tuning device are you using? Can you log data?

[wolf_59]

Tuning with TTS ran data log the next morning on start up when I noticed the engine temp reading stalled watched it for a couple minutes and grabbed the IR temp gun front was 137* rear was 217*
As a test I pulled the front plug wire off my fatboy and installed it on the dyna hooked up timing light and all was good through the warm up cycle reinstalled his wire and still good
Haven't had time to do anything since then will do some more checking and preliminary tuning for cam tuning, IAC warm up etc. next week hopefully it was just a bad connection at the coil or needs a new set of wires

[PoorUB]

Swap the engine temp sensor out with a known good one. Sounds like you have a "spare" handy.

[wolf_59]

Thanks I'll keep that in mind

[Sycho01]

Just curious, problem solved?

[wolf_59]

Seems to have straightened out after swapping the plug wire back was able to get cam tune done before buddy took off on a fishing trip
I'll update when he gets back and I get a chance to do more

[BVHOG]

might want to make sure you don't have a valve sticking.

[wolf_59]

might want to make sure you don't have a valve sticking.

Good Idea! thanks

[wolf_59]

Haven't had any more issues since swapping plug wires around buddy brought it by the other day helped him flash a tune from the FR, He says bike is running great did compression test on the warm engine got 180# F/R
Only other thing I can think of is with the cam tune the estimator showed cam tune at 4/2 and I ended up with 6/2 smoothed out the idle a lot
Probably another one of those things in life I'm not supposed to understand
Thanks to everyone for the advice