Good point Kilroy, might have to try some N9ys, cheap enough to experiment with eh?Kilroy wrote: ↑Thu Jul 19, 2018 6:23 am I use Champion plugs in my 70's motorcycles.
It's what they came with, but most bikes I work on have had NGK's fitted for the same reason - everyone stocks them.
One thing I noticed between the two is that for the same grade of plug - in my case B8ES v N3C - the position of the electrode on the Champion places the spark a little further into the combustion chamber.
I think that is beneficial, especially in the Trident/Rocket 3 engines where the spark plug barely makes it through the alloy head.
Imagine the same might apply to a B series head..
Wow, have you got a Rocket 3 or a Trident? Those ray-gun pipes on the BSA are super cool.