magneto points opening test

[berger]

i have'not been to the pub , but i remember this topic being covered and can't find it, so how do you test for the points opening on a magneto with a dial meter or a digital meter ? but i do remember you can't use the beep beep richie method. please don't say rizla paper my favourite method, i need to know why there is no spark and what readings i should be looking for.

[CheeserBeezer]

Difficult with a meter as the difference in resistance is caused by the primary windings which don't add up to much. You can wire a little buzzer (3v) across the points and listen for a change in tone as the points open.

[sean]

Difficult with a meter as the difference in resistance is caused by the primary windings which don't add up to much. You can wire a little buzzer (3v) across the points and listen for a change in tone as the points open.
[/quote


If you can still hear 

[Joolstacho]

Berger... Rizlas have worked perfectly for many decades... nothing has changed!

[berger]

joolstacho yeah man they work better in my long ens

[philwhitelaw]

The points opening can be detected by connecting a multimeter across the points (one to the fixed side, the other to the moving side) and removing the backplate centre bolt (no electrical path to the primary winding).  This method relies on the backplate remaining in place by its taper in the armature though.  Failing that The Magneto Guys sell a gizmo that will do the job with everything intact.

[limeyrob]

I use a 1 1/2 thou feeler removed from the set. Pinch it between the points and tie a very thin elastic to it. Its very sensitive and you get a feel for when it starts to move.

[Greybeard]

I tried using my digital multimeter set to measure resistance to do this. There was only a small difference between open and closed but a difference was detectable. A ciggy paper was a lot simpler.

[Joolstacho]

...And then!... you had another use for it afterwards!

[Sav]

https://www.themagnetoguys.co.uk/magneto-static-timing-light

Friend of mine uses one of these, have not heard complaints

Moi?? finest feeler gauge I can find.

[JulianS]

I have been using a Magneto Guys timing light for years and it works easily and perfectly.

I have used an SRM piston stop and degree disc to set TDC but you dont always want the primary case outer off when retiming/changing the mag. This service hint from BSA works well with the iron head.

[Billybream]

I have this one off Ebay

[berger]

this is the berger patent no hands needed self releasing timing tool. every home should have one.

[Greybeard]

That electric gizmo must be a simple resistance tester. If you have a meter you should be able to use that.

[fffcycles]

I have an American made magneto timing box. The simple(?) device is sensing inductance which you might find on some good quality digital meters.  The device works a real treat I like using it!
Frank
Got it from an aircraft magneto shop pricey but worth it.