Hi All,
I'm looking to replace my spark plugs on my modofied 120R for maintenance. I was thinking of trying some of the precious metal plugs, maybe an iridium or platinum plug. I have a TMax so the ion sensing issues shouldn't be a problem.

I have two questions though. Anyone have a specific part number for the proper plug and would it benefit me to go to a cooler plug? I ride the wheels off this thing and was thinking it may help control detonation in the heat.
Thanks,
J.

 

32186-10 se platinum hi-compression plug. $19.95 set

 

I've had some great results with platinum plugs on motors that had less than optimal fuel mixers or ignitions, like the panheads.
long life too.

the "heat range" of a plug has nothing to do with the spark it throws- it is the ability of the plug to dissipate heat from the tip.
too hot a plug (less heat dissipation) may become a glow plug and contribute to pinging or dieseling.
a colder plug may help with pinging if the mixture and spark advance are correct.


when i last looked into iridiums ( for an evo) the specs from ngk didn't quite match the specs of the stock HD incl gap and plug reach...I couldn't get any useful answers from NGK so stayed with the autolite platinums which i have used for 20 years.
I have had good results from them- better than bosch which had inconsistent factory gapping- and on these plugs the gap shouldn't be adjusted by the owner


mike