Skeeve, on 18 July 2010 - 09:21 AM, said:
Thanks for that, but doesn't it beg the
real question: How do we graft a Yamaha vr [recognized as being the most rugged/reliable of the J4-branded voltage regulators] onto our Guzzis so we can stop worrying about this sh!t once & for all?

Sorry, I just noticed your question.
The Yamaha charging system is quite a bit different
The Yamaha alternator and I think most other bike alternators are 3 phase (3 wires), the Guzzi is single phase (2 wires)
A 3 phase system gives a much smoother DC from the regulator because there is always one set of coils generating Voltage 120° apart whereas the single phase alternator stops sending power to the battery for a good portion of the cycle. Because of this gap it needs to send higher current pulses to make up for lost time.
The Yamaha (& Suzuki) regulator operates by shorting out the alternator coils when the battery is up to voltage
The Guzzi regulator operates by opening the circuit when the battery is up to voltage.
I guess in theory it would be possible to convert the guzzi to 3 phase but I think at the very least it would mean a new stator. If someone has there stator out they could count the coil slots, the number would have to be divisible by 6 I think or at least by 3
I should point out I'm not a motor winder.
You could just try the Yamaha regulator leaving the third input wire disconnected, it might work but there again the single phase Guzzi alternator might cook it, or cook itself.
Myself, I decided to design my own regulator using much beefier components 50 Amp instead of about 25 Amp. I have most of the parts, just need to find the time.