Horizons Unlimited - The HUBB - Dominator/XR600 neutral switch problem.

I bought an '86 XR600 with a '92 Dominator engine fitted as a project. It was running fine but the wiring was a right mess so I've swapped the loom out of my old Dominator across to the XR. I swapped all the components over too. Battery, reg/rectifier, starter solenoid, CDI, coil, fuse box, all lights, indicators, horn and switchgear. The whole shebang, except the alternator and neutral switch. Now to the weird bit...It all works, lights, horn, sparks, everything...unless I disconnect the neutral switch wire..??? or put the bike in gear. Then nothing works..??..There is still power on all the fuses with the bike in gear but no horn, lights, indicators, starter, nothing. When I put the bike in gear the diode in the fuse box showed volts so I changed the diode...no difference. I've tried disconnecting plugs one at a time but nothing changes. Clutch and sidestand cut outs are over ridden. WTF. I can't figure this out. Anyone got any pointers.????:confused1: