The solution
Dear experts,
I couldn't wait for an answer so I continued deducing. Found the answer. The indicator relay was fried. So I disconnected it, ordered a new one and it worked like a charm.
Thanks anyway!
Dear CB750 experts,
Got myself in a rather irritating position.
After completely rebuilding my engine, my honda CB750 F2 SOHC from 1978 was running like a charm. Then came the aesthetics, was working fine and all. But then disaster struck.
I was trying to redo my electrics. Everything was...