Simulating the ignition is probably easy for an electronics whizz. I'm not one of those, but I can twirl a spanner and use a hacksaw, so I made my 'spark generator' mechanically.

The 4 lobes on the flywheel are not only for spark timing, but also for RC valve operation. I know this as when I was making my box I found that I had to replicate the flywheel lobe timing exactly otherwise I got very strange spark and RC valve control. Diameter of the 'flywheel' doesn't seem to be an issue, but I made mine exactly following the stock dims as it's easier to get the timing right.

What you're looking for is 4 readings over 1 revolution of the flywheel, but they must be timed just like the stock flywheel. So if you think of it as spinning at 1 rpm then you need a reading at 0s, 7.5s, 22.5s & 30s. The final 30s (180 degrees of rotation) would have no readings.

If you can make that box I will have one. I bet it's easy. I can throw a pulse generator together with a 555 chip, but have no idea how to link them or if it would even work.

The stock pickups are variable reluctance, and I think the PGM reads from the trailing edge of the rotor lobes.

quote: "From my understanding one wants more timing advance as the revs increase, which means then spark fire earlier and earlier as the revs increase."

WRONG!

This is how a fourstroke works, but even then it's not a linear advance. A boiler curve on a stroker is asking for disaster!

A stroker tends to advance to max quite early and then retards. The MC28 actually retards to a point where it's practically running on inertia alone! Hence why it makes no mojo. The NSR on pump fuel would want to be around 21 degrees advanced up to about 7000ish rpm, and then retard off to about about 10ish at 11000ish rpm.