When it comes to the recommended or correct spark plugs for the Commando, I'd guess it gets almost as much discussion or debate as the "oil" topic. But will go ahead and ask if the Champion N-7YC is the accepted replacement for the N-7Y. In trying to find the N-7Y it looks like about all I can find are old stock. They cannot be obtained through the chain auto parts stores here in the states. Although they are still availble from Ebey sellers, I assume when the current remaining stockpiles dwindle and are depleted, they will be gone. Since Andover Norton currently sells the N-Y7C for the commandos, I am also assuming they are correct. I believe the C suffix means copper core, but I believe the N-7Y was also considered a copper core plug, so can someone tell me are they the same plug, but Champion has just started adding the C suffix in its' labeling? Have also bought some NGK BP7ES plugs, but the ones I bought were in a Honda box with a Honda part number on the box. Haven't ridden my bike, ('73 Hi-Rider to roadster conversion) enough to make any sort of determination on which works better, but I have already fouled several of each brand. I've kind of chaulked up that fouling to reviving a bike from 40+ years of sitting and maybe still need to do some tweaking. Just within the last few days, it started to idle rough, and the left cylinder seemed to not be hitting like it should. Went to start if yesterday. I started easily and on the first kick, but started and ran on just one cylinder. Checked spark on the left side and totally dead. Replaced the plug, it started instantly and was then idling properly. Was surprised how easily this thing started and how steadily it idled with the dead plug, and only running on one cylinder. Others would know much more than I, but these bikes seem to have a lot of flywheel effect. I've went to the plug cross refernce charts to see other suitable replacement plug, but do other members here have any reommendations?
Commando spark plug
- Thread starter quawk
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johnm
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I have always used NGK BP7ES.
If your plugs are continuously fouling then your carbs may be very worn. What's fouling them? Soot or oil.
When I was young I was very poor and continued to have fouled plugs and bad running. The problem was the carb bodies were so worn the slides could almost go down sideways
. Fuel consumption was terriable.
If your plugs are continuously fouling then your carbs may be very worn. What's fouling them? Soot or oil.
When I was young I was very poor and continued to have fouled plugs and bad running. The problem was the carb bodies were so worn the slides could almost go down sideways
. Fuel consumption was terriable.
Tornado
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I've run N7YC's and BRP7ES plugs for past 6 or 7 yrs in my Commando. No real difference....maybe slightly more reliable starting when running non-resistor N7YC's compared to the NGK's....but that is not a hard fact.
Its not your plug selection causing the fouling....sort that out before wondering down the plug selection path. Running rich or perhaps oil seeping into combustion chamber would be my first guesses.
Its not your plug selection causing the fouling....sort that out before wondering down the plug selection path. Running rich or perhaps oil seeping into combustion chamber would be my first guesses.
marshg246
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I would have swapped the plugs between sides. It's possible that you have a bad plug wire or a bad plug wire to coil connection and installing a new plug simply masked that. If swapped and it still doesn't fire then it's likely very fouled. Non-resistor plugs basically to not open up internally and certainly not enough to stop the spark!
Champion N7YC plugs are still available, just harder to find than the resistor version. BP7ES is considered a match for N7YC however they come gapped too large so much be checked. I have three boxes of 10 N7YC on the way arriving Monday or Tuesday (one box already spoken for).
N6YC-N8YC and BP6ES-BP8ES all should work fine without electronic ignition. With EI you should have the resistor version or resistor caps. I DO NOT recommend resistor or carbon core wire for bikes.
IMHO, the plug heat range is the last thing to consider - must get the fuel/air and oil control right before worrying about the fine detail of the heat range for a street bike. the N7YC or BP7ES are a good starting point for non-EI and the resistor version for EI.
See other threads and beware of knock-off NGK plugs.
o0norton0o
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It's a system. Now that substitution has shown you that your miss was due to an ignition component failure, you should go through the whole system so it's not a mystery to you... That means identifying the ignition module and learning it's requirements (points, boyer, tri-spark, something else,...) identify the ignition wire type (resistor, non-resistor) Identify the coil/s an the wiring configuration (12 volt parallel, 6 volt series, single dual output, etc) Take a multimeter and check the resistance of all your components and compare your readings to the known proper readings for the system you run.
This is one of the ways you chose things like "the best performing plug" for YOUR ignition configuration, because ultimately BPR7es or N7YC (or some other plug) may perform exactly the same to the naked eye when installed, so maybe one of them has a tiny bit less resistance than the other one which makes it better (in theory). WTBS, it might make absolutely zero difference too, but it's good practice to *TEST, NOT GUESS (© concours 2017) and get a handle on the system you have installed!
This is one of the ways you chose things like "the best performing plug" for YOUR ignition configuration, because ultimately BPR7es or N7YC (or some other plug) may perform exactly the same to the naked eye when installed, so maybe one of them has a tiny bit less resistance than the other one which makes it better (in theory). WTBS, it might make absolutely zero difference too, but it's good practice to *TEST, NOT GUESS (© concours 2017) and get a handle on the system you have installed!
