The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: Royalcrown32 on 03.04. 2012 06:43

Title: Spark plugs?
Post by: Royalcrown32 on 03.04. 2012 06:43

Just wondering what type and make of spark plugs work best in a 1960 Super Rocket? I just bought a bunch parts from an old-timer who quit the motorcycle hobby. Including in the lot are lots of spark plugs. Mainly NGK. I don't have any experience with NGK As I always use Champion spark plugs in my Triumphs.

Title: Re: Spark plugs?
Post by: beezermacc on 03.04. 2012 07:56

In correct Super Rocket spec. (357 cam, high comp pistons, alloy head) Champion recommend N3C, which is equivalent to B8ES or B7ES. I think the NGK numbers go in the opposite direction to Champion, i.e Champion N4 runs hotter (retains more heat / has a longer porcelain insulator cone)  than N3 whereas NGK B7 is hotter than B8. I'd start with a B8ES.

Title: Re: Spark plugs?
Post by: BSA_54A10 on 03.04. 2012 11:39

If possible fit a BP6ES or BP 7ES.
The "P" is for "Projecting" electrode.
Modern fuel ( which is nothing like real petrol) will leave an oily film on your plugs when cold which is conductive.
The projecting electrode plugs are less prone to cold fouling than standard plugs.