Best sparkplug for a stock panhead

[ldfly112]

I have a 1961 and a 1957 FLH been using Champion RJ12Y plugs just wondering if there is another plug out there that would work better Thanks

[Rubone]

What do you expect by "better"? And you should not use R type plugs, they are resistor plugs, unless of course you have an electronic ignition and appropriate coil. With points ignition non resistor plugs and solid core wires.

[dukekleman]

IDFLY,

There is far too much hype ( marketing ) put into spark plugs especially when it comes to pump gas street engines. Try not to get caught up in it...

Use the appropriate thread reach, heat range and ignition system capable spark plugs available to you with the correct gap.
Be careful on packaging that appears to have been tossed around, dropped, etc...
Be sure to gap them correctly, meaning tool usage. Center electrode and porcelain damage can occur going unnoticed causing the user to blame the brand of spark plug instead of their inability to use the selected tool correctly.

Lastly, a spark plug can only do it's expected task if the environment in which it lives is appropriate.
Inappropriate Fuel control ratios and oil control issues are a battle the spark plug can only endure so long. Premature spark plug replacement is a sign of these issues.


Hope this helps,

Duke Kleman

[otis71]

Champion J12YC is the crossover. Not sure if they’re still being manufactured but I find complete packs at car swap meets often. Correct Harley 3-4s went obsolete a few years ago but are still easy to find.