Motorcycle Repair: 2002 FLSTSI rear cylinder fouling plug, valve seals, heritage springer

Question
QUESTION: 2002 Heritage Springer 88B with injection. Engine has 74,000 km (45,000 mi.) and has been fouling the rear plug for about 30,000 km. Plug is badly fouled after about 3000 miles (5000 km).

Changing plug frequently keeps it running and there is no smoke or misfire. After the plug is fouled, then it misses occasionally and eventually gives an error code of "no combustion detected" on the rear cylinder.

Now have synthetic (HD syn 3) oil in the engine, and it doesn't seem to use as much oil...but, still fouling the plug.

No compression or leak down test done yet. However, I suspect that this is due to valve seals, and I'm hoping that there is a way to fix this without cracking cases.

What do you think?

ANSWER: You never said if the fouling is wet or dry.
If its dry, then you need to test the plug wires and the coil to make sure they are good.
If its wet, I would do a compression test and see if you are oil fouling the plug.
If you are burning oil, you dont have to split the cases. You will just have to pull the top end
Good luck and happy riding
Mike

---------- FOLLOW-UP ----------

QUESTION: The plug is dry, until it fouls so badly that there is no more combustion...still, not that wet though. Will check the coil, etc...

ANSWER: Dry means that the cylinder is not burning correctly. Check the coil and plug wires. If that isnt the problem then you can have the cylinder remapped.
Good luck and happy riding
Mike

---------- FOLLOW-UP ----------

QUESTION: Sounds good...this has had stage 1 remapping and it was verified last season. Was still the same though, eg no errors or issues. Not sure, does that mean the purposefull cylinder cooling misfire has been programmed out?

I just did a 9,000 mile run in 12 days (round trip) out to Niagara Falls and back to the west coast...all highway, still fouling.

Will definitely have the remapping and spark checked.

Thanks

Answer
The reason I said to remapp was that the rear cylinder is running to rich. If its not the coil or the plug wires then I would have a dianostic run and have the rear cylinder remapped if it passes the dianostic.
I would still do the compression test as well as the bleedown test, just to verfy that the are good.
Good luck and happy riding
Mike