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R51/3 - Setting points (contact breaker gap)

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Micha
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R51/3 - Setting points (contact breaker gap)

Post by Micha »

After all my magneto adventures, taking it apart for overhaul and assemble it back, I lost the points calibration, of course.
Only thing I know about them, is that the gap should be 0.4 mm when engine just opens them.
I understand that the red arrow bolt rotates the system and the yellow marked bolt locks it into place.
The complete bracket with the camshaft hole was bolted to place by me without any reference... I thought it should just be more or less in the middle of the camshaft.
I have no idea of what to do.

Is there a simple way to adjust this contact breaker?
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points.jpg
Michael Steinmann
R51/3 1952
Engine Nr. 529466

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Re: R51/3 - Setting points (contact breaker gap)

Post by schrader7032 »

Michael -

A point of clarification...the gap of 0.4mm is the widest opening anywhere you rotate the engine around, not just when they begin to open. The points has a rubbing block which rides around on a cam surface of the points. At one point, the rubbing block will be the highest on that cam. That is where you need to set the gap using the yellow fastener. Later when you are checking timing, the points should just open when the S-mark appears in the window. If the mark is not in the window, you can try loosening the whole plate with the red fastener and move the plate around to achieve the opening with the S-mark in the window.

This typically comes up but don't get hung up on the 0.4mm gap setting. You can start with that and if you find you can't rotate the whole plate enough to bring the engine into time, go back and adjust the point gap. It can be a little bigger or smaller than 0.4mm...maybe as small as 0.3mm or as high as 0.5mm. A small gap adjust makes a big change in the point where the points open. Even with these variations from the standard setting, the magneto will still function well.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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Re: R51/3 - Setting points (contact breaker gap)

Post by p. museum2020 »

camshaft hole ?

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Micha
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Re: R51/3 - Setting points (contact breaker gap)

Post by Micha »

Kurt Thanks a lot!
Great info, I will do so as soon as posible.

Museum2020 = My appologies, I wrote in a hurry and English is not my native language.
I mean the hole that is in the brass plate, for the camshaft to go through.
Michael Steinmann
R51/3 1952
Engine Nr. 529466

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Re: R51/3 - Setting points (contact breaker gap)

Post by Micha »

I must admit that slowly this issue is getting on my nerves and I am starting to feel waves of despair.
After assembling the whole ignition module, I discovered that I had no spark at all, which was there before, fat and blue, and the engine worked (but with the problems I had).
Then I thought to myself, it must be because of the insulation disc that I did not know where it fell from and where to put it back. Probably something shortens there. I searched in the photos I took before the disassembly, and found that it was (probably) located under the electrical wire connections (red arrow).
I mounted it there and there is still no spark.
Then I thought to myself, that there is a slight chance of a rare coincidence, that although the magneto coil gave healthy sparks before, he was dying and the disassembly and assembly killed him definitively.


How much resistance should I get when checking between both magneto's poles?
What is today the most reliable and simple electronic ignition assembly for my motorcycle model, which will know how to work with the PowerDynamo alternator I have here? VAPE do not stock it separately anymore, I'm afraid.
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points4.jpg
points2.jpg
Michael Steinmann
R51/3 1952
Engine Nr. 529466

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Re: R51/3 - Setting points (contact breaker gap)

Post by wa1nca »

You dont need the old insulator as your new points has the built in white insulator
looks like the white wire is touching the metal on the point plate and it is shorting out the new points
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Ashfield, Ma
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Re: R51/3 - Setting points (contact breaker gap)

Post by schrader7032 »

Notes I wrote down is that the coil resistance from one plug cap to the other plug cap should be around 17K ohms. If the plug caps are non-resistor, then discounting the small resistance of the wires themselves, I would think that the resistance between the two points were the plug wires tie into the coil body, should also be in the range of 17K ohms...maybe 15-17K ohms.

Are you sure that you have the appropriate gap for the points? The points must open and close while rotating the engine. If the points don't open at all or if they don't close at all, then no spark.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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