I am currently restoring this 1969 Kawasaki TR90 and need some assistance with the reassembly.I need the mounting location for the diode / rectifier. The bike also came with the dual rear sprocket option. Anyone have one of these?  I have all the parts, but again the assembly of the arrangement is a bit of a mystery.I have the parts book and workshop manuals, but they are of no help. 

If the main wiring harness is in place and correctly routed, then look for the wires that match the colour of those on the rectifier, and this will give a good starting point.

The battery box and under the spine of the frame, near the coil, are typical locations.

Yes, I already tried the wiring harness fitment and it looks like it is around the battery area, but there is no obvious mounting hole or bracket.

Does photo #6 on this listing help?

1970 Kawasaki G3TR Bushmaster K423-4) battery box switch rectifier electrical | eBay

Selenium rectifier is that square finned piece bolted to the bat box

Thank you, that was just the ticket.