Using NOS plugs - Champion N57R

[Scout63 Profile]

I pulled the plug from my new to me 1961 G80CS and it is a clean Champion N57R. I have never seen this type of plug with a shrouded electrode. I bought a box of 10 of these plugs unused in original packaging on eBay as I couldn’t find them new. Is it ok to use old unused plugs? Is there a better plug for this model? Thanks.

[bjorn Profile]

Hi Ben,
The N57R is for racing only, with an open pipe. The "R" stands for retracted gap. These plugs are good, but can oil up if you have a motor that burns a lot of oil. The N57R corresponds to an NGK B10.

For street use on a G80CS with a silencer, I use a Champion N3 which corresponds to an NGK B7.

regards
Bjørn

[Scout63 Profile]

Thanks Bjorn. Ben

[gtx469]

A good N3C plug replacement I run in my 61 Matchless G9 twin and also my BSA Lightning 650 is the E3.18 plug. never had a spark issue with these bad boys. Its a direct replacement for the N3