Thanks for the info. I found someone had uploaded the
B2910 WSM to Kubotabooks.com a few days ago which had that diagram plus a couple of others that where useful. I also found that the
B2410 WSM has a very similar wiring diagram but with the 40A alternator as factory so with those 2 I worked out how to wire it up. I'll upload the info once I get my diagrams sorted, but basically do as follows:
Run a largish (I used 6AWG) cable from the main alternator lug to the starter lug, this is the new main charging output
Run a short wire from each of the 2 aux pins (Top and Vertical pins) to the blue barrel connectors that the dynamo output originally connected to
Cut off the regulator connector as close to the regulator as possible so you have wires to work with (assuming you don't wan't to keep it, mine was burnt so useless anyway), remove the black and red pins since they aren't needed
Get an automotive 12v 4 pin relay and using the regulator plug you cut off wire it up as follows
Connect the Yellow wire (mates with RedYellow on harness) and the Blue wire that you connected to the Top contact on alternator to the common side of the switch contact and also to one side of the coil
Connect the Green wire (mates with WhiteRed on the harness) to the normally open switched contact
Connect the other Blue wire that you connected to the Vertical pin on the alternator to the other side of the coil
Upgrade the 30A slow blow fuse next to the starter to a 50A one if you want or find the 30A keeps blowing
The main issue is that the old regulator put 12V to the charge lamp on the dash (with the other side of the lamp tied to ground) if it wasn't charging the battery, so the lamp comes on to tell you there is an issue whereas the new regulator is designed so that the charge lamp is across the 2 aux pins of the alternator and the Vertical pin is pulled to ground if there is a fault so the lamp comes on.
So by adding the relay coil across the aux pins and the NO relay contact connected to the lamp (with the other side of the lamp still tied to ground) and ACC (+12V when ignition turned on) on the common pin, if there is a fault, the regulator pulls the aux pin to ground which closes the relay and so the lamp comes on. Basically using the new circuit to trip the old circuit
If you don't care about the fault lamp I think you can get away with just connecting the main alternator output to the starter and removing the old regulator and that's it although you may also need to connect ACC +12v to the Top pin on the alternators aux, not sure about though.
