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Using NOS plugs - Champion N57R

Posted: Wed May 13, 2020 3:25 am
by Scout63
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.

Re: Using NOS plugs - Champion N57R

Posted: Wed May 13, 2020 3:03 pm
by bjorn
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

Re: Using NOS plugs - Champion N57R

Posted: Thu May 14, 2020 11:41 am
by Scout63
Thanks Bjorn. Ben

Re: Using NOS plugs - Champion N57R

Posted: Fri Jun 05, 2020 3:22 pm
by 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

Re: Using NOS plugs - Champion N57R

Posted: Fri Sep 10, 2021 4:44 pm
by jmbradford
These recessed plugs were designed for use with the CS heads that have the firing slot in the head as there is a risk of compressing the bottom electrode of a normal spark plug with these heads. I have used several NOS N57R in the past and they work OK , they might be a bit cold for some road use and are not to easy to start if oiled or flooded.A good magneto is a must for easy starting.An FE220 is similar style plug which you will see mentioned in the books too.