1600 CC Vulcan (Mean Streak) Rear Cylinder Spark Plug Fouling
Our 2008 Mean Streak has the following symptoms: The rear cylinder right-side spark plug is extremely dark (significant buildup) and the remaining 3 spark plugs appear normal (insulator color, tip, etc.). This condition was first noticed at 5,000 miles. I changed all plugs (DPR6EA-9 with .036 gap), torqued the plugs and rechecked at 8,000 miles. Same indication. Cleaned the plug and rechecked at 13,000. Same indication. Here we are at 20,000 miles and this has become "normal" for this plug.
The dealer has checked the bike twice and found nothing out-of-spec. I've always run top-tier premium fuel (per the OEM Manual)......Shell, Mobile, BP, Chevron. The bike is not "lugged" and I ride one-up (180lb rider).
Question: has anyone experienced a two-plug-per-cylinder issue similar to the one I have tried to describe??? Thanks in advance.
'08 Meanie SE