06 RT spark plugs...again

[tbryant]

Today I purchased Autolite 4163 spark plugs. They are cataloged by Autolite as proper for the 06 RT. The problem is that they have an 18mm hex instead of oem 16mm and now there is a fit problem. I had already had to turn down a 16mm socket. Has anyone run into this? Solution?

Terry :doh

[AZgman]

Yep, BTDT. My solution was to return the plugs and order the proper Bosch ones from my local NAPA store.

[markgoodrich]

Last December I called NGK's U. S. tech line and got the following answer regarding plugs for the hexhead:

"BMW calls for NGK DCPR8EKC plugs, available only through BMW dealers in the U. S. It's a dual ground plug (that's what the "K" designation means) with a nickel tip (the "C" denotes nickel).

The exact plug, only better, is widely available at less cost as the NGK DCPR8EKP, with the "P" denoting platinum tip, thus longer life.

The tech guy recommended against their iridium plug or their single-ground plug, as he said not only do the plugs not extend as far into the combustion chamber, but they don't provide as complete combustion as the duals. [I realize many use the singles, I'm simply reporting here].

Most auto parts store sites require input of your car info...use a BMW M3 and you'll get the right plug. Or, order from Amazon, get free shipping, no sales tax, works out to about the same. They're about $12 each, everywhere I looked."

I put them in the bike, and they have about 20,000 miles on them. I pulled two out after about 10k; they looked new.

Harbor Freight has a very cheap long spark plug socket which works just fine.

[tbryant]

Thanks Mark. I saw your thread in the archives, I appreciate your research. I ended up installing Champion RA6CH (809) which took a lot of research but in cross referencing backwards I arrived at these(relying on 27 years automotive parts experience). They are a copper plug, single ground electrode...$1.99 each at Pep Boys. The idle immediately smoothed out(I am replacing OEM NGK with 40K miles on them, the bike has almost 76K on the clock).

I am leaving Thursday on a 4500 mile trip, will see how they hold up. At 2 bucks each, I can replace them at every other oil change and come out ahead, way ahead. I consider it a challenge to find substitute parts that are equivalent, at a fraction of the OEM price. I am a cheapass, I just happen to own a $20K motorcycle!

Terry