questions about ignition system

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mauricedonini

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Hi,

I bought my first English motorcycle recently - a 1971 Norton Commando 750 Hi Rider.

Couple of questions about the ignition system.

1. The motorcycle has electronic igntion. On the board it has the letters IGAV. Any ideas what is IGAV?
2. Coils - one Lucas 17M12 and one Lucas 17M6. Suspect one is for 12 volts and the other is for 6 volts. Does this matter? (Note - The bike has a 12 volt battery)

Thank you

Maurice
Shelton, CT
 
Pics be good, as for some ignitions run 6v coils and some 12v, the stock Commandos with points ran 6v coils with a ballas resistor and seems your bike has a mixture of coils, but running two different voltage coils could be probmatic and some EI will run 6v or 12v coils depends on the brand, I know my old boyar ran 6v coils when I installed it back in the late 70s.
 
mauricedonini said:
1. The motorcycle has electronic igntion. On the board it has the letters IGAV. Any ideas what is IGAV?
Click to expand...
All I can find on IGAV is an ignition module for Kawasaki and John Deere engines (below). I've never heard of such a system for a British bike so perhaps more information is needed.

"IGAV ignition refers to the ignition module for certain Kawasaki and John Deere engines."


mauricedonini said:
2. Coils - one Lucas 17M12 and one Lucas 17M6. Suspect one is for 12 volts and the other is for 6 volts. Does this matter? (Note - The bike has a 12 volt battery)
Click to expand...
Yes it normally matters. The two original coils would be 17M6 fed from a ballast resistor in the 12V system. When most electronic ignitions are fitted the coils are normally connected in series instead of in parallel as they would be for the original points ignition.
 
Last edited:
I think you may find that whomever installed the electronic ignition has rewired the coil electrical connections and possibly bypassed one of the coils.
Dennis
 
mauricedonini said:
Hi,

I bought my first English motorcycle recently - a 1971 Norton Commando 750 Hi Rider.

Couple of questions about the ignition system.

1. The motorcycle has electronic igntion. On the board it has the letters IGAV. Any ideas what is IGAV?
2. Coils - one Lucas 17M12 and one Lucas 17M6. Suspect one is for 12 volts and the other is for 6 volts. Does this matter? (Note - The bike has a 12 volt battery)

Thank you

Maurice
Shelton, CT
Click to expand...
Is it a runner or not???
 
ashman said:
Is it a runner or not???
Click to expand...

Not really.

I was able to start it twice the other day. Nothing but failure the last 3 days.

Additional info about the motorcycle;
Mikuni VM 34 carb has been cleaned. Fresh gas. New plugs. Oil in the sump drained. Battery has 12.5 volts.
 
Last edited:
mauricedonini said:
Not really.

I was able to start it twice the other day. Nothing but failure the last 3 days.

Additional info about the motorcycle;
Mikuni VM 34 carb has been cleaned. Fresh gas. New plugs. Oil in the sump drained. Battery has 12.5 volts.
Click to expand...
When cleaning a mikuni VM you have to remove the pilot jet and run a wire through it
Also incase you don't know
When you use the choke it's actually an enrichener jet you need to have the throttle shut for it to work
We need to what electronic ignition you have to be able to help
But generally a pair of 6v coils are used
Also we need to know what spark plugs and spark plug caps you have
You don't want to be using resister type plugs and resister caps ,it's one or the other not both together
 
Plugs - the motorcycle came with NGK BP7ES. It now has NGK BPR7ES. There are two different spark plug caps/wires. One is Beldin. One - Lucas. Markings are feint.

The carb was cleaned because the two times I was able to start the bike, it would run on choke/enrichener but die with the choke/enrichener off.

I did pull the plugs out and kick the motorcycle over. Spark was their on both plugs but not very strong. Also only seems to spark during the last quarter of the kick.
 


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