66 N15 Ignition question

Paul W.

Paul W.

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May 12, 2018
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Hey all! I'm new to the forum from the Pacific Northwest area. I've owned several motorcycles, including a '69 Bonnie. I recently acquired a '66 N15CS and I'm sure I'll be picking the brains of those who are much more familiar with these than me.

While I'm waiting for my Amal carb rebuild kits, I do have a few questions.

I noticed that the bike does not have a keyed ignition. Are they supposed to? It is equipped with a magneto. Which leads me to the magneto. I do not have any spark when I kick it over. I haven't pulled apart the kill switch as of yet, but I intend to. Where can I find a wiring diagram for this bike? It came with a Haynes, which I'm not terribly fond of their motorcycle books and have a Clymer on it's way, but the Haynes does not have a schematic for this machine.

Thanks,

Paul
 
If you think (hope) the kill switch is the problem you can take it out of the ignition circuit by simply disconnecting the ground wire from the magneto cap/cover. There's probably a knurled round nut or a small regular nut securing the wire to the cover. It is this wire that is grounded when you depress the kill button so disconnecting it takes the kill switch out of the circuit. I'm not specifically familiar with the N15, but most magneto ignition ignition bikes do not have keyed ignitions. The ignition "system" (magneto) doesn't have anything to do with the electrical system so no reason for the two to share a switch.
 
Do you have/know how to use a VOM? If so, disconnect wire at magneto per Bodgers reply above. With meter on Ohm scale, connect one meter lead to magneto wire (probably white), and the other end to frame ground. Meter should read open circuit. Press kill switch, meter should read closed circuit. If so, kill switch is OK.

If kill switch passes test, and still no spark, it suggests bad capacitor inside magneto body. Unfortunately, not a DIY fix. Report back.

Slick
 
Thinking a quick test to see if the mag is totally dead would be to take the points end cover off - should screw off by hand - in a dimly lit or dark shed/garage and have someone kick the bike over. Should see a spark at the points in the mag if mag has any life left. Unfortunately this will not tell you how healthy the mag is and a mag that has not been rebuilt in recent history by someone who is competent is probably not going to give a reliable good spark even if it shows spark when crudely tested. There are multiple ways for mags to age badly. (See Texas Slick's post above and, for example, recent posts on Dominator 99 with K2f). Suggest usual precautions when dealing with an open spark: good ventilation, no gas nearby and fire extinguisher handy.
 
texasSlick said:
Do you have/know how to use a VOM? If so, disconnect wire at magneto per Bodgers reply above. With meter on Ohm scale, connect one meter lead to magneto wire (probably white), and the other end to frame ground. Meter should read open circuit. Press kill switch, meter should read closed circuit. If so, kill switch is OK.

If kill switch passes test, and still no spark, it suggests bad capacitor inside magneto body. Unfortunately, not a DIY fix. Report back.

Slick
Click to expand...
I'll run the test when I get home today. Have plenty of DMM's, being an electrician. ;) Also, I read your post about magnetos yesterday. Very informative.

Bodger,

If it's not showing any resistance, I'll pull the cover off as mentioned. It's definitely not the easiest space to work in.
 
Kill switched works fine. Resistance on mag to ground starts at 1 ohm and settles in at .5 ohms. Seems low to me.
 
No experience with Joe Hunts but by reputation they are more rugged than Lucas which would have been original fitment on your bike.
 
I dont know Joe Hunt maggies, but armature resistance on K2F is in the amount you measure ..... it is likely OK. An open circuit would be death.

Are points breaking?

Sorry, but I cannot offer any more help on Joe Hunt. I hope you get it resolved.

Slick

PS ... I agree with Bodger's post above.

Edit ..... something just occurred to me ..... there was a thread recently that discussed Joe Hunts mounted behind barrels, as opposed to hanging on the timing cover. Per this thread, heat from the barrels tended to kill the super magnets. Try a search for more info on this point.

Edit #2 .... If it is dead magnets, send it back to JH. JH will likely replace them with more heat tolerant magnets, which that thread I mentioned says are now available.

Edit #3 .... here is a link to thread with discussion re: rear mounted JH
https://www.accessnorton.com/NortonCommando/lets-talk-magnetos.24122/page-7#post-355450
 
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I'll try in the next day or two to pull the cover off to check the points. It's a real bear to get in there.

Thanks for the links.
 
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