Contact breaker shorting?

1down5up

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Oct 17, 2014
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Hi all.

A question regarding the contact breakers on these old Nortons.

Im timing an atlas with a k2fc lucas and the "newer" (I believe) style of contacts.

When using the multimeter across the contacts when they are open I have continuity. The bike seems to run fine but this doesn't seem right.

Shouldn't the one contact effectively be isolated from the other when the points are open? And if so shouldn't that mean that the bike shouldn't run properly?
 
1down5up said:
Hi all.

A question regarding the contact breakers on these old Nortons.

Im timing an atlas with a k2fc lucas and the "newer" (I believe) style of contacts.

When using the multimeter across the contacts when they are open I have continuity. The bike seems to run fine but this doesn't seem right.

Shouldn't the one contact effectively be isolated from the other when the points are open? And if so shouldn't that mean that the bike shouldn't run properly?
Click to expand...

You are actually measuring the resistance of the low tension windings. It's so low it looks like nil resistance.
 
If you remove the long screw that secures the contact block to the magneto shaft, you can then measure closed circuit with the points closed and open circuit with points open. With the screw in place, it is as Triton says .... you are measuring the internal coil resistance.

Using small alligator clips, connect one lead of a VOM, set up on Ohm scale, to either lug A1 or A2, and the other lead to lug B, as shown in the photo below.


Contact breaker shorting?


Slick
 
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