Anybody ever seen these?

[Omarttentmaker]

I was looking thru my spark plug collection today, and these turned up. They're 18 MM with screw-on knurled nuts to hold the "shepherd's crook" ends on old coil wires. The thing that got me is that they're stamped "Harley-Davidson", as you can see in the pics. I thought the only 18 MM plugs that Champion made for Harley were the 2-piece kind.

Attachment 25566
Attachment 25567

[Rubone]

Those were sold alongside the 14mm versions when there was a #2, #3, etc, in both thread types, not sure when they quit with them though.

[Omarttentmaker]

Thanks, Rubone. Maybe they were for servicars.

[Rubone]

Servi-Cars after 56 had 14mm plugs. H-D went by the 10 year rule in those days supplying repair parts, so those were just replacement parts sold over the counter, never stock in anything. Since they are just Champion plugs with the H-D logo like all the plugs in that era it was no big deal for Champion to stamp them with the H-D name rather than their own, same as they did on the 14mm versions.

[Omarttentmaker]

So WL's up to '52 and servicars up to '56 came from the factory with 2-piece 18 MM spark plugs?