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[Phantom6722]

Got 96 Heritage and the other day I changed the plugs the front plug looked fine but the back plug was sooty, both exhaust look the same could the timing be out of whack? As well when the bike is idling the rear exhaust note seems to pop a bit more that the front exhaust. Any ideas what the problem (if any) could cause the back plug to be sooty?

[spydglide]

Got 96 Heritage and the other day I changed the plugs the front plug looked fine but the back plug was sooty, both exhaust look the same could the timing be out of whack? As well when the bike is idling the rear exhaust note seems to pop a bit more that the front exhaust. Any ideas what the problem (if any) could cause the back plug to be sooty?

Is it carb and does it have a manual choke( 'enricher'?  Sometimes running the enricher too long when warming-up will cause a plug-fouling condition.  spyder

[prodrag1320]

do a leak down,a bad valve seat can also do that (sooty plug & poping)

[HILLSIDECYCLE.COM]

Got 96 Heritage and the other day I changed the plugs the front plug looked fine but the back plug was sooty, both exhaust look the same could the timing be out of whack? As well when the bike is idling the rear exhaust note seems to pop a bit more that the front exhaust. Any ideas what the problem (if any) could cause the back plug to be sooty?

Check the plug wires first, then move to what Kirby said.
Scott

[Phantom6722]

Thanks Guys for your input. I did a compression test 6 months ago and both cylinder were +100 psi and within HD specs. I have Crane duel ignition coils and Fireball HI-E module set to single fire –multi-fire. I will reverse the wiring for the coils to see if I transfer the occasional popping problem to the front cylinder as well as check the timing and VOES setting. If it’s not an ignition timing, coil or plug lead problem then Kirby can you explain how to do the leak down test.

[cahdbiker]

Phantom6672, before you do anything ride the bike with the new plugs and see if the results are the same. It could be as simple as a bad spark plug. This has actually happened to me. Plug looked good, but was not working .  If it was the choke it would effect both plugs. Always check the most simple thing first then work your way back from there. Don't forget to check the plug gap. Leave your rear plug in, pull plug wire, put another new plug in rear wire, start the engine( I know it will be running on front cylinder only), see what kind of spark you see when you  ground it to the engine. Also a bad spark plug wire is a big possibility. I had a plug wire that was rubbing on something under the tank and was shorting out because of that. Check your coil could be a bad connection. Good Luck CAHDBIKER

[HILLSIDECYCLE.COM]

.......................and ALWAYS, if an electrical issue is suspected, start at the battery, and work outward.
Scott