They may be the same heat range but the center electrode on the RA8HC is longer so if you gap it to .40 you have to bend the outer electrode where it's not square with the center electrode. Compare the two and you will see the difference. For an xtra $3.00 a pair I'll take the correct plugs.

 

I've been using the RA8HC's for years and the electrode at .040 looks just fine to me.

Here is an xref list


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That's all I've ever used in my Sportster or TC engines as well...

I don't know.

 

Did'nt say they won't work, what I said was they are not the same plug put them side by side you'll see what I'm talking about. Looks like the RA8HC is made to run a narrower gap

 

I use the Screamin Eagle Triple Platinum and love them as does the bike. I bought 2 sets and just switch them out from 1 year to the next.

 

I run the Harley 10R12 in my Nightster,it is a cooler plug from the Buell,seems to help with the pinging.

 

If you first bend the electrode too far then slide your gap tool toward the center of the plug then bend the electrode back to the correct gap you can get the electrode square no matter what the gap is.
(hope you understand what I mean, I could show you easier than tell you)

 

DPete, I've seen that on the Champion plugs as well. The ground strap ends up about .005" out of square if you set the gap to .040" at the narrowest point. For an extra buck apiece, I use the 6R12's.

 

Now that's exactly what I mean.