mag not working - was fine!

[StephenG80]

OK just finished rebuilding my primary drive and go to start her and no spark - not a thing. Mag and spark were big fat and beautiful when I took her off the road. She has been standing for about 12 months without being started. Pulled the pick up off the ring -all looks dry and shiny - points have not been touched since last run. Where would folk start to look for the problem? Continuity all good from pick up through to spark plug center electrode.

[spookefoote1956]

Condensor? Electrickery! I was once told to put a mag in the airing cupboard for a couple of days if it had been standing a long time.

[Janet]

Start with the easy and cheap things. Change the plug. Even when it was perfect the last time it ran, for some strange reason, it doesn't necessarily mean it is now. Condenser if it has one. (I know nothing about magnetos so wouldn't know ) Check and clean any component and wiring, even if it shouldn't affect it. A clean over the point's faces may be sensible. Is getting a spark dependent on having a good earth? Keep doing this until someone comes along who knows the answer.

[g80csp11]

had a similar problem on a bike the other week after a rebuild ( not mine )
doing all the prestart checks tappets , timing , plug , new oil etc..
all stopped when we got to the timing check . nut on mag was not tight so despite turning over engine the mag was not turning
Fixed than and all was well

have you had the mag off , or had the sprocket off ?

[StephenG80]

thanks for all the comment so far - I have touched nothing to do with the timing or the mag, so no reason I can see why it should suddenly stop working

[clive]

Clean the points with a piece of doubled over fine grade paper or similar. When left unused the points oxidise and prevent the transmission of current. In regular use the sparking stops this happening.

[Janet]

Of course, all Stephen's work will be wasted if hasn't got a gremlin trap.

[StephenG80]

Ok - gremlin trap on order! and i cleaned the points - - just done a wee check with the meter - I have continuity between the points when open - can't see any dirt etc which is creating a short between the top point career and the insulator gasket to the base plate - so presumable this means something has "collapsed" internally. not sure whether to or cry -any ideas? been a while since I worked on points - hope I am being stupid and it is something very obvious.

[Rob Harknett]

You could leave magneto ignition bike standing for a year and find no spark. Using some folded wet & dry 320 /280 grade approx. to act as a file. Give the points a good clean, as Clive mentioned. Dry 1/2" paint brush can be used to clean off dust which may hold moisture. Fit a new plug. If you have not got a new plug. Try the old dodge that was used in bygone days, I have not heard mention of for years. Clean the plug electrodes with a lead pencil. Which I believe leaves a deposit like gunpowder. Don't be surprised if it now starts first kick.

[StephenG80]

yes - but that does not solve the little issues of continuity even when the points are open.