Ignitor problem or wiring harness? No spark on #2 cylinder.

[Venturing Sole]

History: in June 2011 (about 68,000 miles on my 2006 RSV) coming back from Maintenance Day bike suddenly ran a little rough and had poor highway performance. Muffinman helped do a color tune and we discovered #1 cylinder (left rear) had no spark. Replaced coil and plug cap and all was well again (in retrospect, coil was probably not bad, just needed to re-engage plug cap on the wire, but I’ll never know for sure). In July 2014 (about 105,000 miles) and a week after Sleeperhawk helped do a valve shim job (everything running great except cruise control), suddenly #4 cylinder (right front) wasn’t firing (exhaust hardly warm, heavy gas smell, gas dripping from carbs). Re-engaged plug cap on coil wire and all was good again (except cruise control still not responding to “Set”). Two weeks ago (about 110,000 miles) I changed the oil and suddenly #2 cylinder (left front) wasn’t firing (exhaust cold). Unscrewed and re-engaged plug cap, no difference. Tried again in case I didn’t do a good job, still not firing. Ordered a coil and plug cap (note that #2 coil has a shorter wire than #1 and #4 - and #2 is probably the hardest coil to get to). Installed new coil and plug cap and still no spark.

Then I searched the forum and came across several threads with recommendations (primarily from V7Goose) circa 2011 to eliminate possibilities. I unscrewed the plug cap from the new #2 coil wire and put a nail in the wire to check for spark...nothing. The front two coils are too far apart to swap the spade connectors, so I confirmed #4 coil was generating spark by laying the plug against the engine...yep. Removed #4 coil and put it in #2 mounting location and attached spade connectors and put new #2 coil in #4 mounting location and attached spade connectors. New #2 coil hooked to #4 cylinder generated spark, so the coil assembly seems ok. The known good #4 coil assembly hooked to #2 cylinder produced no spark. Put the new #2 coil assembly back on #2 cylinder and put old #2 coil assembly on #4 cylinder. Old #2 coil gave spark on #4 cylinder, so I probably didn’t need a new coil after all (oh well). New #2 coil on #2 cylinder still no spark. No surprise at this point.

Although it is probably a moot point, I checked resistance across the spade connectors of both new and old #2 coils and original #4 coil (on my workbench). All measured 4.3 Ohms. I could not get any readings on the meter when I put one probe in the end of the coil wire and one probe on any of the spades or the mounting posts. Also could not get any readings when I touched one probe inside the plug cap and the other probe to the screw end. Again, probably a moot point since I physically swapped coil assemblies and always got spark on #4 cylinder and never got spark on #2 cylinder.

Is the conclusion that the ignitor is bad? Is there a way to eliminate the wiring harness?

Looking at the wiring diagram, all four coils have a wider spade red/black wire which goes to the engine stop switch. #1 coil (left rear) has an narrower spade orange wire that goes to the cruise control and the ignitor. #3 coil (right rear) has a narrower spade yellow wire that goes to the ignitor. #4 coil (right front) has a narrower spade white wire that goes to the ignitor. #2 coil (left front) has a narrower spade white wire (although diagram says it should be white/green) that goes to the ignitor.

It appears ignitors cost about $500. Would like to have confidence this is the problem so I don’t throw $500 after the $100 I wasted on the coil/plug cap. Can a dealer check function of an ignitor off the bike?

Amy other tests I can perform?

Appreciate any help.

David

[V7Goose]

The ignitor may be bad, but it is a simple job to test the wires to each coil first.

 

The R/B wires are all connected to a common 12V supply coming from the kill switch, so just disconnect that wire from the coil and check it for 12V with the key on.

 

As you have already seen, the other wire on each coil goes to a specific pin on the ignitor. To test that, just remove the plug from the ignitor and use an ohmmeter to check for continuity from the pin in the plug to the end of the disconnected wire at the coil.

 

If you have continuity on the wires, the ignitor is almost certainly bad. HOWEVER, just removing and reseating the plug on the ignitor MIGHT fix your problem - sometimes pin connections can build up a thin layer of oxidation that is fixed by simply reseating the connection (scrapes the surface of the pin). Pilots used to HATE it when we wrote up a repair as simply "reseated unit", but it was not an uncommon fix. Good luck,

Goose

[Neil86]

While having the harness unhooked at both ends for continuity test also test the wire

vs battery negative to ensure there is not a short to ground in between coil and igniter as this will prevent firing spark plug too.

No aftermarket tachometer connected to the #2 coil?

Edited November 9, 2014 by Neil86

[Venturing Sole]

Aftermarket tach is connected to #4 cylinder and mounted on brake reservoir. Will check continuity as suggested and report back. Thanks for comments thus far.

[Venturing Sole]

Removed the ignitor and performed a continuity test after sorting out all the wire colors compared to the Clymers manual. Manual shows a white/green striped wire to #2 coil, but in fact is a light grey. Wires for coils #2 and #4 checked out ok. Cleaned up the ignitor and the connector pins. Also cleaned up the wiring harness connector which had a lot of grit mixed with dielectric grease. Re-installed the ignitor and battery and checked for spark...voila! Spark! Set gas tank on to confirm cylinder would get hot. We got heat! All reassembled. Haven't test ridden yet, but pretty sure this problem is solved. Still have a cruise control problem, unless a miracle occurred in re-seating the ignitor. If cruise still not functional, that will be another thread. Thanks for the troubleshooting advice. Our forum is invaluable.

 

David