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Does anyone have any idea what rhe MK ll total spark advance is or a published advance curve by rpm ?Cant seem to find any information on this subject,as I have been building digital electronic distributors for vintage machines and have had this square four in my collection for a long time.now turning to its revival and adressing the ignition system.Fuel is next.
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I seriously doubt that the exact range in degrees is critical.


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Aye !!

Have a look at the distributor for it.
It may even be marked for the advance-retard range.
Or you could measure it.

Commando unit is marked as 12 degrees.
(So thats 24 degrees at the crankshaft).

Modern electronic units often have a totally different advance curve
than the old mechanical systems, and are often better for it.
Experiment ?

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I agree,consistency is as important as the right advance at different rpm levels.Been building these for vintage indian 2 cyl Scouts,Chiefs and the modern curves work amazingly well as this module has 8 curves from 24 begrees to 35.After all its a 4 stroke air compressor add air fuel and spark.Balance that and
the fuel gives great performance.
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I'll look through my info and see if the advance is listed. There are UK solid state upgrades- their literature may also help.

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Originally Posted by Newburgh M/C
Does anyone have any idea what the MK ll total spark advance is ..........
Here's distributor advance specs for a 1956-59 MK2 Squariel. This is from a Lucas Equipment and Spare Parts book. If yours is an earlier year, the advance range is the same back to '52-'53 but the distributor part number changes. Hope this helps.
Model: DKX4A
Part #: 40486A
Supercession #: 40426
Advance range: 14-16 degrees.


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