Hi Guys.
Hope someone can shed some light on my problem. Just finished a 1200 (S&S cylinders and pistons) conversion of my 883 Iron. Also did a tank lift/wire tuck and coil/key relocation using DKCustoms kit. Already had Cobra PowerFlo air filter and V&H 2-2 Big Radius pipes. Using PowerVision tuner with a map from DynoJet. Idle set at 1000 rpm.


Bike started first time (a little to my surprise because as a novice mechanic I assumed something would be wrong!). Idled just beautifully at 1000 when warmed up. Started the break-in ride and then things started to go awry. While riding gently at 50 mph, 2500 rpm bike started to lose power/chug. Came to a stop and noticed idle dropping to 750 rpm and immediately up to 1500 rpm, then back down to 750, back up to 1500, and so on. Stopped motor and retrieved DTC from the tuner. Had DTCs P1352 (Front Ignition Coil Driver High/Shorted EFi) and U1097 (Loss of Speedometer Serial data EFI). After 5 minutes or so bike started up again without a problem. Tried to limp home slowly but same problem occurred with same DTCs.


Left bike overnight. Started up again this evening and idled just fine. Went for a ride and after a few miles same problem but no U1097 DTC this time, just P1352. Let bike cool and started up again without a problem. Switched ignition leads to see if problem would now show up as rear coil issue (could probably then assume ignition lead problem). However no difference to problem or DTC. Noticed problem seemed to only occur when temp reached about 180C (about 350F).


My problem is I am unsure what to do next to try to determine the exact problem. Any ideas?


Seaplane.

 

Update:


Started from cold and let idle. Reached 110C (230F) and problem started again. Using a piece of paper at each exhaust (advantage of 2-into-2 exhaust) it is obvious the front cylinder is losing compression when idle drops to 750, regains it at 1500, loses it again, etc. Stopped motor and restarted immediately - initially fine but problem recurred after 20-30 seconds. I think it's an intermittent loss of spark to front cylinder suggesting a coil issue but surely simple relocation of coil shouldn't cause it to malfunction?

 

Year, model and mileage on the bike?

 

2012 Sportster (883 Iron). Only 2000 miles on clock.

 

The symptoms sound like a bad coil, but the bike is newer/lower miles than you typically see bad coils start showing up.

What do the plugs look like? Have you tried another set or switched them?

 

Plugs look perfect (however already have new set on the way which I will try).

 

Did you flash the ECU for the 1200 setup? Its a different ball game now with that setup.

 

Years of troubleshooting electrical problems has given me a motto "what's the last thing human hands touched" in your case you changed a lot of things, good possibility you have accidentally crushed a wire or cut through the insulation . when things heat up they expand and maybe ground out. go over the wiring that you touched just to check.

 

Hi Cool Inferno. Re. ECU flash: Yes. Used map from DynoJet for 883 to 1200 cc with best match Air filter/exhaust (emailed to me rather than a self initiated download so I assume it should be okay).

Hi Baird. Good motto. While I was as careful as I thought I could be I am now planning on removing tank again to make sure all wiring is sound especially the relocated coil wiring.


However the more I look into ECU mapping the more I think that this may be the issue (possibly low VE to front cylinder) so I plan to start with a suitably adjusted map and try to autotune the bike over the next few days.

 

I would do that, if anything start with a slightly modified map and go with the autotune. Try not to lug the engine to much during the break in so that you don't have problems with the piston rings.