27-08-13, 05:57 PM
Well I'm delighted for you that it's definitely fixed at last, and if the stuttering moves to the donor bike that'll be confirmation that the regulator is to blame.
How it's doing it is a mystery though. Maybe there's a dodgy connection in there that resonates at certain engine revs and puts out enough noise/radio frequency interference that it swamps the signal from the pickup... feels a bit far-fetched, but normal regulator faults result in the battery not charging or overcharging.