best plugs for thundermax

[itsafatboy]

Wondering what are the best plugs for tmax or does it make any diff. i was going to go back to the copper plugs like stock was using the iridium ,  but have heard the copper have the best spark am i way wrong ,  116" 11.1 comp softail

[Appowner]

I don't see where the ECU cares which plug is used as long as it fits OEM specs.  All I see the ECU doing is telling the coil when to fire the plugs.

[Tynker]

 

[SP33DY]

I attended a 3 day ThunderMax training session and they showed us that a certain condition in a trouble report was traceable to iridium spark plugs. That was about 7 years ago, and my memory won't let me be more specific. Their saying was "Iridium? Get rid of 'em!"

[Appowner]

That could very well be but is the issue some kind of conflict between the T-Max and the plug or simply that the iridium is not as good as some thought?

Would the same issue have been present had the bike had the OEM ECU?

[bobrk1]

What  does  thundermax  recommend ? I  had my  bike  dyno  tuned  and  he  said  I could  only  run hd  factory  plug  not  even  the  screaming  eagle  one  otherwise  would  trip  anti knock , bike  been  running  great last  70k.

[Coyote]

I didn't think TMax had knock detection.

[smoserx1]

That could very well be but is the issue some kind of conflict between the T-Max and the plug or simply that the iridium is not as good as some thought?

I had always thought the H-D only plug requirement applied to just Delphi EFI Bikes with ion sensing knock detection (because of the feedback).  I have a carbureted bike and just changed out a set of iridium plugs with nearly 50000 miles.  They are very good indeed.

[bump]

I have been using Champion plugs in my twin cam for years, no problems. It came with stock harley plugs but it went back to dealer 2 times in 2 months, they changed plug wires and coil. Got check engine light about 5 miles from dealer. Stopped on way home and got champions, light went away and haven't had that since.

[jmorton10]

 I have a t-max on my 124" RK.  It runs fine with whatever plugs I put in it.

~John

[tdrglide]

I have been using champion RA8HC for years on my TC's. Both Delphi and Tmax. Never any spark plug issues
However I just went down to local napa to get some and was told they had to order them   so I went the autozone and was told by them "no longer available"   so over to O'Reilly and they have them on the shelf 

[Hossamania]

Hope you bought extras.

[Ohio HD]

Never trust the gurus at the parts store. Champion isn't discontinuing the RA8HC.



RA8HC Champion