i had a quick go before leaving for work this morning so didn't have time to do any thorough tests but once i connected the diode and spun the wheel it went into resonance... used a 1n4007 since it was handy. Probably should have used a lower value.

turned the pot right down so that there were only the 100 ohm base resistors but couldn't break resonance... possibly because the diode had a too high resistance...

I have a big chunky diode I salvaged from a vcr that has only 150 ohms resistance so will try that when I get home...

What do you expect will happen Aaron? wouldn't it counteract the 1n4001?

Richard - Definatly not proof positive! and I am not saying it improves the circuit... it just has an interesting effect. and of course I'm sure it will vary from machine to machine... like a said, i hooked 2 relays in series and it had negative effects so it is very likely that the value of the choke is important and will probably vary from machine to machine.

But did your friends machine display the same behaviour? Does he have a scope?

and you say amps dropped but so did rpm... were these drops proportional?