Champion vs NGK
Up to Commando
Hi Chaps - my Norton Commando is supposed to run on Champion N7Y plugs but I've fitted NGK BP7ES as an equivalent - it's proving a bugger to start (old fuel doesn't help either). I noticed that the sparks on the NGKs are rather weak (Tri-Spark Classic Twin EI + Tri-Spark coils.) I connected a multimeter across the NGK plug top cap and the centre electrode (at the plug 'nose') and got a high resistance. I tried this with another BP7ES plug and got the same result. As a reference I removed one of the Champion N3s from my Rocket 3 and did the same measurement and got a full 'short' (which is what I'd expect - i.e. a simple copper core). I know that plugs with an 'R' suffix denotes 'resistor' i.e. suppressed - I thought that perhaps the 'S' in the NGK code also denoted 'suppressed but apparently it simply denotes 'standard core size'. Any ideas ??
Cheers,
Mark,
Probably a totally odd idea, but how about running Champion N7Ys? Ran them ever since I had my first Commando- now 35 years- road and race, never had a spark plug problem. Part# 06-2348 from Andover Norton if you can't get them locally.
Sorry, I forgot- the easy solution is not what people write in forums for. So pester any number of spark plug specialists instead and stay well away from the obvious answer........
Hi
I used to run my Commando Metisse with 10.25 C:R using NGK BP7ES (plus Boyer Ignition) and it used to start first kick. I've worked on a couple of bike recently where the owners were convinced they had an ignition problem only to find that one of the carburetter pilot jets or passage ways were blocked. It's worth a try!
N:B The concentrics that don't appear to have a pilot jet do (of sorts) - it's hidden away in the passageway behind the pilot jet screw.
Regards.
Ian.
Hi all - as a follow-on - today I brought 4 x brand new Champion N7YC plugs. When I got home I did my 'test' - two of them passed - i.e. full short from top connector to nose-end electrode. The other two had high resistance. I fitted the two that 'passed my test - they gave great fat sparks and with fresh fuel the bike started second kick (after a six month lay-up) and ran beautifully - what is going on with these plugs (NGK and Champion) ??
Note that the plug leads are copper but with 5k plug caps (as recommended by Tri-Spark etc.)
Cheers
The only problem I know off is if one severly floods the carb at first start with brand new plugs and thus soaks them in petrol for their first spark. They just die an instant death. Remember that from our rotary racing days and, no, we did not use Champion plugs in the rotary racer.
Put a Bosch plug in a Triumph (or Norton) and see how long it works. On Triumphs (real Triumphs, pre-1985) I give them a week at most. No idea why it is so, it just is!



