Hi all, Im new to the forum, but have been reading up here for awhile. I have a 1985 RoadKing.

The previous owner was running Champion RN11YC4 plugs, and they have quite alot of carbon on them, although the carb tuning was off, now corrected. I noticed the factory recommended champion plugs are RN12YC. My questions are: which is the "Hotter" plug(differences between those two plugs) and which would you recommend I run?

Im also thinking about going to a different brand(if there is something better) but wouldn't know which of the two part numbers to cross-reference.

Thanks in advance!

 

Take a look here

https://www.hdforums.com/m_70378/tm.htm

https://www.hdforums.com/m_65226/tm.htm

The 11's are a colder plug than the 12's and as long as they are not fouling would work well in the motor