Spark plug advise needed

I have always stuck with Champion N7YC but non resistor plugs are being fazed out so I stocked up on them, 6 plugs will last me forever now.
I have ran with NGK and my Norton didn't like them, but others have no problems, just got to find the right heat range for your motor and work around resistor plugs.
 
JAMES CHRISTIAN said:
Can someone tell me what type spark plug I need to run with the Old Britts power arc ignition?
Click to expand...
OEM are:
Champion N7YC
NGK BPR7ES (...or no "R" for non-resistor if you can find them)

I'd think the coils being used make more of the difference in plug gap than the ignition setup type, no? If stock coils, stock compression, normal pump fuel, then go with the OEM spec plugs/Gap & heat range.
 
Re multispark ignitions. FWIW, above 1500-1800 RPM they deliver a single spark, just like a standard ignition.

OTOH, they are capable of delivering a lot more power than stock ignitions and can provide a good spark under high engine loads on modified engines where OEM ignitions might be inadequate. And because they DO provide multiple sparks at low RPM, they can also smooth out the idle/make starting easier, especially on highly modified engines...and probably on kickstart Nortons! :)
 
MexicoMike said:
Re multispark ignitions. FWIW, above 1500-1800 RPM they deliver a single spark, just like a standard ignition.

OTOH, they are capable of delivering a lot more power than stock ignitions and can provide a good spark under high engine loads on modified engines where OEM ignitions might be inadequate. And because they DO provide multiple sparks at low RPM, they can also smooth out the idle/make starting easier, especially on highly modified engines...and probably on kickstart Nortons! :)
Click to expand...
Are they typically running higher output coils or just the oem coils? It is the coil output that determines spark power, not the EI as that just manages the timing of cycling 12v on/off through coil primary windings AfAIK.
 
" It is the coil output that determines spark power, not the EI as that just manages the timing of cycling 12v on/off through coil primary windings AfAIK."

It is actually the ignition's output to the coil that determines the "power" capability of the spark. The higher the ignition-to-coil voltage, the great the potential spark output. Multispark ignition "boxes" may not require a different coil though typically, folks also change the coil at the same time. OEM point ignitions were often "enhanced" on performance builds to produce a more powerful spark by removing the ballast resistor. Of course this increased wear and, if the coil was not capable of handling the additional voltage, would cause overheating/coil failure over time. It is the robustness of the coil that is involved - basically the wire gauge - to make a "High Performance" coil.

FWIW, the actual spark voltage at the plug does not increase with a "more powerful" ignition system. The voltage necessary to jump the gap is all that will be generated. IOW, if it takes, say, 20,000 (20kV) volts to jump the gap under whatever load conditions, that is all that will be generated, even if the ignition can produce 40kV. There is no performance benefit to a higher powered ignition if the stock ignition can jump the gap.
 
MexicoMike said:
" It is the coil output that determines spark power, not the EI as that just manages the timing of cycling 12v on/off through coil primary windings AfAIK."

... There is no performance benefit to a higher powered ignition if the stock ignition can jump the gap.
Click to expand...
Unless you increase the plug gap, then there may be an improvement.
 
Tornado said:
OEM are:
Champion N7YC
NGK BPR7ES (...or no "R" for non-resistor if you can find them)

I'd think the coils being used make more of the difference in plug gap than the ignition setup type, no? If stock coils, stock compression, normal pump fuel, then go with the OEM spec plugs/Gap & heat range.
Click to expand...
NGK BP7ES are still available (they are my preference, given most plug wires are resistor-type these days and I don't want to double-up with both resistor wires and resistor plugs). They just changed the model designation to 2412. Same plug, frequently although not always marketed under both numbers.
 
Figuring that the NGKs I have always used were gone, I started ordering Champions from Andover whenever I had a parts order. Nice to know NGKs are still available.
 
My Norton using NGK BP7ES always got a mis fire after running a week with them, and I have used a few when Champion had a bad batch all them years ago, but my Norton runs so well with the Champions, never had that problem with them and with the Joe Hunt I get even longer life out of my plugs, just changed them after 25k mile and they still looked as good as the day I put them in and running just as well.

Ashley
 
James,
Tornado got it right: it's BPR7ES 5534 Post #4.
I believe Fred at Old Brits, mentioned these need to be resistor type to work with this E.I. system, which came with it's coil pack and Hi Tension wires and the plugs mentioned.
So a kit or package with two power curve settings programmed that you could switch to either, depending on your fancy. It has a rev limiter as well. I have mine set to 6800 RPM.
Kenny Cummings of NYC Norton put me on to this E.I. system at one of the International Norton Owner Association Rally's. Years gone by.
Cheers,
Tom
 
Last edited:
I ran NKG BPR8ES in all of my Commandos. I'd start with 8's and they are not fouling I'd stay with them. Seems like for NGK's only the resistor type are available now. If you choose them don't run resistor wires.
 
I use a Power Arc ignition and the installation manual says to use BPR7ES gapped at .025. It’s a real easy ignition to set up, top dead center and turn the optical encoder disk until the LED lights up, tighten it down and you’re done.
 
Is anyone else selling these units on the Norton Commando market since Old Brits retired?
granttiller.com

Grant Tiller | Norton Commando Wiring Diagram + Power Arc

I have fitted a Power Arc electronic ignition to my bike. These are sold, I believe exclusively for Norton Commandos by Fred and Ella at Old Britts. This is a brilliant company to deal with, polite, efficient and courteous. What Old Britts don't know about Norton Commandos isn't worth knowing...
granttiller.com granttiller.com
Some would like to Know.
cheers.
 
Last edited:
seattle##gs said:
The Power Arc works very well with a starter motor. If the bike is still a kick start it will always take many kicks to get it started
Click to expand...
You need to get a full revolution on the crank before the counter see the timing. If the bike crank goes backward from compression on a slow crank then it might not count proper advance. Its counting backwards on the disk from compression going backwards.
Hit the kill switch after you push it over the top. Kick again. should be good.
 
htown16 said:
I ran NKG BPR8ES in all of my Commandos. I'd start with 8's and they are not fouling I'd stay with them. Seems like for NGK's only the resistor type are available now. If you choose them don't run resistor wires.
Click to expand...
Are you using the Power Arc Ignition system?
 

Similar threads

Q
Commando spark plug
Replies
9
Views
687
norton bob
norton bob
jms
Spark Plug Recommedation for 1967 Atlas
Replies
9
Views
253
Schwany
Schwany
Britstuff
1974 850 MK II Norton Commando Clutch Basket Advise Needed
Replies
4
Views
576
Britstuff
Britstuff
jms
Spark Plug Caps for Atlas Lucas Magneto
Replies
6
Views
174
johnm
johnm
arcpoint
Amal carbs and spark plugs issues and concerns
6 7 8 9 10 11
Replies
209
Views
8,236
acotrel
acotrel
Back
Top