My brother owns a 2002 GS500.  His engine has died at 40k, so we have bought a very rough GS with a good engine which we have just swapped in to his bike today.

The donor GS is a 1999, so there are a few differences. Namely the wiring from the stator, and the carbs are a bit different too.

We've got the engine installed and haven't touched his electrics since they were last on and working properly, however when we turn the key nothing happens apart from a single click from a relay.  No lights, nothing.

So a few questions to hopefully get us started:

1 - Do the stator wires need to be connected to the regulator/rectifier for the bike to turn on?  The 99 stator wires are bullet connectors, whereas the 02 is just a standard plug.
2 - Are any of the electrical components different between the 1999 & 2002 bikes? We have everything from the other bike so can swap if needed.

We have checked the usual suspects - ground is connected securely to the engine, battery is fully charged, fuse is good (swapped the power connector thing over with the other bike as well and no difference),

I don't think this is an issue with the neutral/side-stand/kill switch, as the lights would still turn on.

Anyone got any ideas on this one?  Thank you.