Ignition problem

[kjell.dahl]

Hi!
I have a VH500 1951. After 15 yaers the magneto was a little bit tired. I change to another magneto but another problem came in. When I drive and try to advace the timing to a good point, suddenly the engine stops fireing. When I put the leaver a little bit back it starts fireing again. The exhaust pipe has allso a blue coloure, it had not before. So the ignition is little bit late I suppose.
The question is why I can't advance the timing enogh? It is correct adjusted 1/2" before TDC fully advaced.

Regards Kjell!

[paul.jameson]

The blue exhaust pipe means overheating which is usually caused by the ignition being too retarded. Is your replacement magneto the same as the original or is the advance retard cable connection on the other side perhaps? Some serious checking of the replacement magneto is called for but a better option would be to send the original magneto to Tony Cooper for a rebuild.

[nevhunter]

There are a number of different face cams available. If you have the wrong one it may not fire all through the range, There is a small letter stamped on the section where the fibre lifter doesn't touch. It should have " L" On it. Nev

[kjell.dahl]

Thank's for the replies. The cable connection is ok and the face cam is right as far as i know. I'll check the letter. An idea! Can it be wrong angle on the shaft in comparsion to the windings? I have read somewhere that its important that the windings are in right position when the ignition starts.

[nevhunter]

If someone had mixed the condenser end of the armature from an AJS type magneto with the magdyno type there could be an error of the relationship of the rotating points assembly with the orientation of the poles in the armature. If you get a good spark across the whole range of advance -retard that is oK. It's normal to have a slightly weaker spark when retarded. Most people don't start fully retarded anyhow for that reason. You should get a useable spark across the whole range. Nev