1998 CBR1100XX I seem to blow regulators on this bike that is new to me. I have replaced 3 regulators now (salvage parts) that worked properly when I first replaced them, then they stop charging the battery after a 2-3 hour ride. The stator puts out 75 VAC with no load on each of the three legs so seems fine to me. I removed all the fuses from the fuse block then measured the resistance to ground on the load side of the fuse to look for shorts. The headlight and taillight fuses (circuit A and C) measure less than 1 ohm to ground which seems low although I never blow any of these fuses. I have looked for shorts but haven't found any. Everything electrical (taillights, headlights, ignition, horn etc.) works on the bike as expected other than it doesn't charge the battery fully. BTW the battery is new.
After a 200 kM ride I was barely able to turn the engine over after stopping briefly to rehydrate (beer). I removed the headlight fuse and managed to drive all the way home and had a fully charged battery when I arrived back home. WTF
Help!! I 'm pulling out my hair on this one and I have precious little left.

 

I would still suspect the generator coils breaking down when hot and under load.


When the bike has had a good run and is nice and hot :

Check the battery voltage first with ignition OFF - should be 12.7 ish

Check battery voltage at tickover - might be higher than ign off cos the BB dont charge at tickover.

Check battery voltage at 2000rpm or above - should be 14.5 ish

 

Problem resolved: bad connector wiring on regulator. At some point water must have gotten into the female connector wiring. The connection to the regulator became intermittent. The connector was not available from Honda so I terminated the wiring with Stakon crimp lugs, crimped first then soldered so this doesn't happen again. A short piece of heat shrink tubing and I was off to the races. Wiring the regulator is a snap all the yellow wires location don't matter only the the black and red have a unique location so I marked them regulator with colour matching paint.