Runs then shuts down

Hi guys
I am at a loss, My Lady is a 6volt AC magneto m/c I stripped down the ignition after it start once ran for 10 seconds then shutdown,there was no spark, I then replaced the points checked the ignition coil and all seemed ok.It started and ran again for 10 seconds shutdown and now no spark. The ignition switch checks out, is it safe to make a simple ignition loom and has anyone any ideas.
I only need to sort this now before getting an MOT
Regards Tufty

Have you tried a new spark plug?

Apart from that I don't have any ideas.

Are you sure you don't get a spark anymore after 10 seconds?
You're sure there's still fuel going trough the carb?
(this sounds like the regular vacuum problem - try running the bike with the fuel stop dismounted)

Otherwise, check the ignition cable.
Also, your mass cable (massa '-'/negative - wire) to the frame could be badly connected.
Check for errors in the cable loom.
If you want, you can dismantle the loom: disconnect every part except the ignition and make sure all the wires that have something to do with the ignition system are in a perfect working order.
If it works that way, the problem is somewhere (a short cut,...) in the wire loom.

Did the bike got wet recently?

Hi Waynus
Yes there is fuel when I remove the plug to check for a spark the plug is wet, I was going to run a new -Negative wire from the battery to the bike frame to see if that would help, and is there any way of removing the ignition coil without removing the engine.
Regards Tufty

TUFTYNUTKIN wrote:Hi Waynus
Yes there is fuel when I remove the plug to check for a spark the plug is wet, I was going to run a new -Negative wire from the battery to the bike frame to see if that would help, and is there any way of removing the ignition coil without removing the engine.
Regards Tufty

Unfortunately not, you will need to drop the engine to get to the 2 nuts that hold it in place. The engine is held in by 2 bolts but you will also have to remove the air filter housing as well to get the engine off (or the carb).

You can reach it by removing the fuel tank as well.
But... you have to drain it first, and (ask James) it can be quite difficult to get it back in place.

Ow, forgot this: You also need to remove (when going trough the engine side)
- the exhaust
- the chain or front sprocket (depending on the chain tension)
--> the chain cover and flywheel cover
- carb (or drain the tank and just remove the tubes)