Mag Timing Sequence

[dave16mct]

You can't do that with a mag. You have to use fag paper or one of the special magneto timers (about £30). I bought one but actually I find the fag paper is just as easy. For coil ignition the old tip (60's Motorcycle mechanics Magazine) used to be to turn the 'transister radio' on tuned off station. When the points started to separate you'd hear a noise through the speaker.
Dave.

[Groily]

Yup, and the reason you can't with a mag is because the primary resistance is only about half an ohm. Not enough to dim a bulb across the points so you can't do it that way, using a battery; and for many meters, that's too small a difference to detect reliably. Often, there will be about 0.2 or O.3 ohm showing when the points are shut, and sometimes more. That's either the meter being slightly 'off', or the points aren't squeaky clean or mating perfectly.
Gizmos can be good, trannies can do it, and fag paper always works!

[spookefoote1956]

I'm going to do a compression test tomorrow. Does anyone know the target psi for a 1956 500 single please

[Joker_Bones]

Ohhhh.... Now I'm puzzled.
What I have been doing is connecting my multimeter across the closed points, it reads 1.0 which is what my multimeter reads when the probes are touched together.
Then nudge the engine forward till the reading hops up to 1.5 or 1.6 and considered that was the when the points opened?

[SPRIDDLER]

I'm going to do a compression test tomorrow. Does anyone know the target psi for a 1956 500 single please

Around 100 psi I think is the general idea.
2 or 3 kicks with the throttle held wide open.
If the reading's low (70 to 80 'ish) put about half an egg cup of oil in the cylinder - if the reading increases the rings are probably worn, if they don't it may be a leaky valve or head gasket.

[spookefoote1956]

Cheers Nev

[ajscomboman]

I'd have said more around 125psi is very healthy.

[SPRIDDLER]

I'd have said more around 125psi is very healthy.

I could probably achieve that as well if I ate more pies. (But I wouldn't be very healthy).

[Andy G]

Ohhhh.... Now I'm puzzled.
What I have been doing is connecting my multimeter across the closed points, it reads 1.0 which is what my multimeter reads when the probes are touched together.
Then nudge the engine forward till the reading hops up to 1.5 or 1.6 and considered that was the when the points opened?

Technically, bumblebees can't fly, but somehow they do.
If she runs like that don't be puzzled, bee happy

[Groily]

You've done well J-B, and have a decent enough meter - the extra half is the difference, yup. So if it shows it reliably, you're there, done and dusted.