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I'm getting a spark on the safety spark gap above the dynamo

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Micha
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I'm getting a spark on the safety spark gap above the dynamo

Post by Micha »

Description of the phenomena I get (do not know if there is a connection between them):
Checked valve & ignition timing.
I start the engine. Left side heats up in seconds to too high a level, I am forced to turn off the engine.
Right side cold to the touch (apparently not working).
While engine idles, I get on the right cold side this spark jumping above the magneto safety system, as said in the subject.
I have a good spark on both spark plugs.
Key is not shutting the engine down, I need to pull the sparkplug cover off from that left overheated side so kill the engine.
edit: this one was fixed: a wire was broken from its solder drop on the ignition switch plate
Can't start right side by itself, again - apparently not working.
The bike run very good before I put it aside 4 years.
Pls note that these copper extensions where made by one of the PO's. They work well :?
Attachments
magneto.jpg
Michael Steinmann
R51/3 1952
Engine Nr. 529466

butch housman
Posts: 256
Joined: Mon Mar 23, 2015 8:57 am

Re: I'm getting a spark on the safety spark gap above the dynamo

Post by butch housman »

This is interesting.
I'm surprised that one of the wrench gurus hasn't gotten u straightened out by now. U say "I have good spark on both spark plugs" ???
U can't have a spark on the plug if u have a spark jumping the mag gap. Hmmm???
Looks to me like u need to go back to basics here & sort things out like why is one side heating up so quickly & how r u judging that? Is the pipe turning red hot right away? If so NOT GOOD! Spark could be seriously out of time or some kinda valve timing issue. It would be good to hear more abt that.
The mag & surrounding area looks generally unsanitary & the coil body appears to have been wrapped with tape at some time, maybe. If so that's a sign that the mag coil has broken down & someone tried a makeshift repair. These r almost never successful, alas. I suggest u get some brake cleaner or starting fluid & spray everything under the front cover & get it cleaned up. Do u have a good plug wire & cap on the right side. Is the ignition timing reasonable?
& yes I notice the homebrew mag safety gaps....WHY? In general terms anyplace u find an unusual owner mod is a place to start looking for trouble. I suspect u have a bad coil but that might not be the case.
Good luck my friend,
Butch

butch housman
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Re: I'm getting a spark on the safety spark gap above the dynamo

Post by butch housman »

Maybe the air gap on ur homebrew mag safety gap is too small. I don't know exactly what that is supposed to be but the only time u should throw a spark there is when u pull a plug cap.

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schrader7032
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Re: I'm getting a spark on the safety spark gap above the dynamo

Post by schrader7032 »

The safety gap on my R69S with magneto is supposed to be 10mm.
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'78 R100/7 '69 R69S '52 R25/2
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Micha
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Re: I'm getting a spark on the safety spark gap above the dynamo

Post by Micha »

Thanks, magneto was wrapped by PO just before I got the bike. Rode it well and it was a first kick starter.
That's why I'm so confused. Can't understand where to look for.
Michael Steinmann
R51/3 1952
Engine Nr. 529466

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Micha
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Re: I'm getting a spark on the safety spark gap above the dynamo

Post by Micha »

schrader7032 wrote:
Sat Apr 24, 2021 11:19 am
The safety gap on my R69S with magneto is supposed to be 10mm.
Yep, measured that as first check. It's 10-11 mm.
Michael Steinmann
R51/3 1952
Engine Nr. 529466

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Micha
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Re: I'm getting a spark on the safety spark gap above the dynamo

Post by Micha »

Could it be a magneto wrapping failure...?
Michael Steinmann
R51/3 1952
Engine Nr. 529466

butch housman
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Re: I'm getting a spark on the safety spark gap above the dynamo

Post by butch housman »

when things set around for yrs parts go bad
there was a reason the coil was wrapped i suspect & it had some kinda problem early
if i'm not mistaken u also had issues with fuel maybe...have u looked into that ?
is ur plug wire broken ?
what have u checked ?
hard to diagnose without more background

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Micha
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Re: I'm getting a spark on the safety spark gap above the dynamo

Post by Micha »

Sparks are new.
Cables for them - are new.
I will try to swapp those cables and see what happens.
Michael Steinmann
R51/3 1952
Engine Nr. 529466

Daves79x
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Re: I'm getting a spark on the safety spark gap above the dynamo

Post by Daves79x »

You safety gap between the added-on copper bars is most certainly less than 10mm. The little pointy projections are still on your mag frame and that's what you should use to measure the 10-11mm from and get rid of the copper bars. I'd start there first, but your coil may certainly be suspect too.

Dave
Dave

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