BSA A10 magneto issue... no spark

[piston jockey]

Hi all,

Slowly getring there with my BSA A10 golden flash 1954.
Currently i'm experiencing magneto problems.
As in... I have no spark.
When I rebuilded the engine i've bench tested the magneto and it had a good clear blue spark.
Now mounted it doesn't give anything!
I've cleaned the brushes, points, sparkplug cables... but still nothing.
Any ideas what the issues might be?

Grtz

Nick

[Bess]

Hi,
     This link may help:

http://brightsparkmagnetos.com/DIY/index.htm

Best wishes...

[TTJOHN]

Make sure that it's turning firstly, if you had a spark when bench testing there is no practical reason why it should not be okay when fitted, I have known that sometimes when fitted, the gear can slip on the taper, obviously, this would also put the timing out, the other thing you could check is whether the cut out button on the end of the mag is shorting, going straight to earth.
HTH

regards TTJohn

[JulianS]

If using the points assembly with steel backplate make sure that the spring on the moving contact is not touching the cam ring, make sure the little backing spring is in its proper position and not displaced to one side. Both would earth the points and stop the mag sparking.

Does not apply to the brass points assembly.

[piston jockey]

Hi,

Thank you for the replies.
So I've already did the following without any results.


- It's turning around as it should (contact breaker assembly and automatic timing control)
- cleaned the points
- cleaned the slipring
- cleaned the earthing brush
- disconnected all other electricity (including cut out)
- Measured the sparkplug cables
- cleaned and slightly grinded the pickups


Hope I can draw some more knowledge from you guys and get it solved!

grtz
Nick

[DerekAnderson8]

When you bench tested the magneto how did you turn it over?

I ask this because you should get a spark against the body of the mag from a bare lead when turning by hand.



Derek

[piston jockey]

Hi Derek,

I've just looked at the video and can't see which way i'm turnjng it by hand! It was focused on the wires! But it looks like it's going clockwise...which apparently is the wrong direction!

I'm going to take it off once more and test it again! What could it mean if I turned it clockwise?
Probably the polarity is wrong.. ?


Grtz Nick

[piston jockey]

Hi all,

I've got it solved. 

The contact breaker assembly shaft wasn't correctly fitted.
Which resulted in a assembly that didn't not following the surface of the cam as it should.

Time to start her up!

thx & grtz

Nick

[DerekAnderson8]

excellent news hope you get it started!

[Marka10]

While we are on the subject of Spark

What spark plug would you recommend for a A10

I have Champion N4c

[DerekAnderson8]

i have Ngk B6es in my K2F mag powered tribsa