I've gone through my '79 Husky 390 OR - it has good compression, seals, reeds and the coil produces a healthy spark.

Problem - after I start it (not too friendly), it just doesn't have the "giddy up" that a 390 should have.

I'm assuming the the Motoplat coil also has electronics that advances the timing (like a CDI) inside the plastic enclosure.

Maybe the coil is OK but the spark is not advancing? Or is it supposed to advance?

I can get a new coil that works on all these old Huskies - it appears to have a module mounted on the outside (according to my source). It's made by a manufacturer other than Motoplat.

Anybody have any insight on the problems that can arise with these old Motoplat ignitions?

PVL seems to be the go-to place for vintage electrical components. Spendy though.

Is a coil adaptable from another ignition on husqvarna? if not what makes them unique from other systems?

I can buy an after market coil for about 150$ (it fits all similar Husky's). But then the bike beats me if I change everything until I hit on a winner.

Besides, I'm too cheap to keep throwing money at this old vibrator.