Magneto - Starting & Riding Advice

Started by Badgerman, March 02, 2023, 08:57:31 AM

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Thomas

Thank you, Sigarus, I will try to manage it. Cheers, Thomas
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai
(MSCR member)

Sigarus

That's true, spare cables are important. However, I wonder how to install an adv/ret cable with a mushroom end on the mag side. It's difficult in the shop, not to mention on the street. Does anyone have any ideas on this?

Thomas, the end of the mushroom into which the cable fits should stick out a bit from the magneto when the cable adjuster assembly is removed. Disconnect the A/R cable from the lever and there should be enough just enough slack to get the cable end fitted to the mushroom. Refit the adjuster at the mag end and refit to the lever by getting the cable end in place first, then pull the outer until it slots back into the lever.


oggers

Full choke may also stop it, sticking your hand over the carb intake definitely will, but yes as Paul says, ex vv lifter is the accepted method. If the adv/ret cable breaks, then I seem to recall that just moving the cam ring with fingers via the "mushroom" head can get you retarded enough to get you away if the engine is cold. The cam ring seems to stay in position - being actuated both ACW/CW by the cable. Mind, this was not on a Sunbeam - rather an Ariel. Mag/points arrangement is the same though.... 

Thomas

#4
That's true, spare cables are important. However, I wonder how to install an adv/ret cable with a mushroom end on the mag side. It's difficult in the shop, not to mention on the street. Does anyone have any ideas on this?

I would assume that one can start the engine even with a broken cable by removing the mag cover and turning the disk with a screwdriver. But that's only a theoretical guess.

Thanks a lot, Thomas
1946 BSA C11
1937 Sunbeam Model 9
... and a scratched Hyundai
(MSCR member)

Badgerman

Great thanks Paul - I guess a spare cable in the toolbox is a good thing ;)

phutton

Pretty much correct, except that the valve lifter is usually used to stop the engine. The engine should still run on full retard, and if it doesn't I would wonder if the ignition timing was set correctly. The advance/retard would have been tight-wire advance originally, so if your cable breaks, you would have extreme difficulty starting the engine.

P.

Badgerman

Morning - guys, just wondered if you could confirm my understanding of the timing procedure for the model 9. I'm way off from trying to start the bike but wanted to get it clear in my head first:

Cold Starting:

1. Retard the ignition by about 1/3 (retard further if kicking back).
2. Once started, move immediately to full advance and ride away.
3. If under heavy load the bike starts to struggle, retard the ignition to the point where the bike picks up and then move back to full advance.
4. When slowing down to a stop or moving slowly (engine to be kept running), retard the ignition back to a point where the bike ticks over nicely and move to full advance again when pulling off?? Not too sure about this part.

5. If you want to stop the bike, just fully retard the ignition and it will stop. Do people use other options for stopping the bike? I used have a ground wire from the mag on my Norton race bike, that when pressed, cut the ignition.

I hope the process in principle is correct and I do understand that every bikes different.

Really appreciate the help
James