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Magneto Timing


MochetVelo
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I translated the Frech manual and find there is a mark on the flywheel: "ALL". This must mean something like "TDC" in French(?). Anyway, it says to align this with a mark on the magneto gear and the descent of the exhaust valve of cylinder #4. I can't see any mark on my magneto. Anyway, I assume the spark is required just past TDC. The setting may be tricky as the magneto has no spark advance.

Thanks,

Phil

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Edited by MochetVelo (see edit history)
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  • 2 weeks later...

We succeeded in setting the magneto timing and starting the engine today. Here is what we did to time the magneto:

Turn crankshaft until piston #1 (the one in front) is at TDC (Top Dead Center: as high as it goes).

Mark flywheel to indicate this position.

Open front of magneto to view rotor. It should be positioned over the contact connected to the #1 spark plug. Sometimes, the magneto gear has a line on it to indicate this position. Our Bosch also had the letter "D".

Tighten connection of magneto shaft to engine shaft.

We then tried starting the engine with the crank. It wanted to kick back, so we retarded the spark slightly. This is done by turning the magneto shaft slightly anti-clockwise (opposite its normal direction of rotation). If the spark occurs too early, it can throw the crankshaft backwards and injure your arm. A couple more cranks and it started!

This magneto has no retard/advance lever, so the timing must be set as efficiently as possible, but mainly to avoid kick-back on the starting crank.

If this in in error, feel free to correct me, but I though I'd post our results in case someone refers to this thread in the future.

Phil

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You got it running,,,3 cheers,,,If you crank too slowly,,it MIGHT kick,,but too slowly and the mag wont spark,,,If you open the plug gap it can turn faster before sparking,,a tradeoff,,some motorcycles are set up this way also,,It can work but its a tradeoff,,,,for me I would look for a mag w/a turning breaker box,and hide the retard wire/handle,,,Good luck Ben

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