No spark after a few seconds!!

[Andrew]

Hi everyone , hope I can get help, my beloved R67 is sick!! its been running fine until yesterday when I went to start it and as usual it fired straight away but after a couple of minutes the engine died just as if I had pulled the key out ,so I started again first kick and again died .. this went on ..if I go back to it after awhile 9times out of 10 it starts then quickly dies .So ive changed the condenser , borrowed a good coil and tried it ..started and died no spark at the plugs its not the kill wire in the headlamp , my only other thought is magneto rotor -could that be the problem if so how to solve it ...I need help please
Worried Andrew. P.S ive taken the rotor off and the magnetism is very good a small spanner/wrench will pick the rotor up
[what is inside the rotor that could go wrong]?

[Daves79x]

Are your wires and spark plug caps new? We had one do that sort of thing and that's what it turned out to be. But I wouldn't rule out your coil kill wire is not bare somewhere and grounding out.

Dave

[jwonder]

Andrew, sorry to hear that! A few things I would check:

1) Are you sure there is no spark? I don't want to question your methods, but I know I have had this happen to me as well and I thought there was no spark when in realty I was not able to see it because I was too busy kicking or the plug was not properly grounded on the head. I purchased one of these https://www.amazon.com/gp/product/B06X9RC3PF and it works great and lets you see the spark better. It also lets you control the gap which will let you know the power of the spark!

2) If you have no spark, and you are sure of that, I would certainly be looking at the kill wire because you have looked at almost everything else. Disconnect the kill wire from the coil and start he motorcycle. If it continues to run you know the problem. You can always kill it by touching the wire back to the coil.

3) As long as the magneto has a decent amount of magnetism, and yours does if it gets picked up by a wrench, I would say it is fine. When I had a few of mine done at a friends shop who ONLY works on Mags for the past 40 years, race cars, etc etc. He told me that the magnetism of the magneto is only an issue if it does not have any pull or very little. He said with our setups it is not that important to have it at top magnetism. I still have mine done because I have a friend who does it, but if I didn't have that available I probably would not worry about it too much.

4) Are your points corroded? You did not mention them so I figured I would ask.

5) Is the coil properly grounded? Either the ears ground the coil or there is a wire on some aftermarket ones. Corrosion could make it not have a good ground.

Hope some of this helps.

James

[Tinkertimejeff]

Before you go to deep or get to frustrated check and make sure your key switch is working properly. Pop the headlight lens assembly out and completely isolate (stick a piece of skinny cardboard between them) the grounding contacts for your coil. If it solves the problem you have a few options to fix it.

[Andrew]

Thanks , for your help unfortunatly all the suggestions that have put forward are ones ive tried .The coil I took off and put a replacement on..nothing [when I say that it did fire up momentarily then went off, the isolation of the kill wire I disconnected [both ends h\lamp and coil] . I removed the rotor and examined it could not see anything , presumably there must be a coil inside the rotor sealed in , could it be that at fault? James thank you for the idea of the plug sparking or not , but i got a friend to look at the plugs in the dark workshop while I kicked it over, so not that ,but I take your point.

[wa1nca]

https://www.amazon.com/gp/product/B06X9RC3PF
I like it
ordered 1 today
Tommy

[Werner1111]

https://www.amazon.com/gp/product/B06X9RC3PF
I like it
ordered 1 today
Tommy

I'm doing the same. Thanks for the tip James.

[malmac]

You have some really knowledgeable people here to help. Sorry I'm not one of them.

My old boss used to say. When you think it's electrical, check fuel and when you think it's fuel check electrical.

No harm in suggesting the ridiculous. Of course as soon as it stops, there is no spark, magneto has stopped producing one.

Mal

[Andrew]

Thanks everyone for your help ,I think [pretty sure] ive found the problem ... the plastic insulater on the points that the leads from the coil and condenser are attached has broken down [cracked] causing a power leak ! new set of points and so far so good . Watch this space !!!!