During a ride I had only one bulb at rear light working.
Then that one failed too.
That made the bike stop, no power to ECU nor fuel pump!?!
Had a spare bulb, put that in, all power normal & continued ride.

Q:
Do I have normal wiring, has a PO done some funny wiring or do
I have a electrical gremlin?

I wouldn´t wonder knowing the electrics of the P750, but on the other hand that would mean that your bike wouldn`t run with the lights off which for sure isn´t normal (or is the taillight always on even if you switch off the lights?!)

G.

in Aus you cannot turn the lights off...but I wouldnt think that faulty globes should stop the bike from functioning...the ECU has nothing to do with lights
you definitely have some sort of wiring gremlin

You must have electrical gremlins in there somewhere.

sounds like a short that will turn into a long

Shorted filament in a bulb can do this sort of thing

The two main electrical problems on bikes relate to bad earth connections (which tend to kill components) and corroded connections which cause components to stop working.

Sounds like a combination of bad earth and corroded connections in this case, with the new bulb providing an alternative earth path.

The new bulb will only provide a temporary solution, and is probably masking something far more serious that may take out your CDI unit for instance.

The best solution is to strip the bodywork and remove all earth straps, one at a time clean them with electrical connector cleaner, clean the place on the frame where it connects with sandpaper. If the earth straps cannot be cleaned well then replace them.

For connectors take them apart, clean with electrical connector cleaner and 600 grade sand paper and reconnect. Some pertolium jelly aids waterproofing. Where a connector is in a particularly bad position wrap in denzo tape. Replace connectors where the wires are corroded or the connector pins cannot be salvaged. Solder all new connectors. Wrap split loom tape in self adhesive insulation tape (not the stuff with glue, but the one that you stretch over itself) and waterproof the loom as much as possible.

I have bought several non runners in the past sold cheap because of electrical failure. Spending a day sorting connectors and earth points have resurrected 2 of the 3 bikes (907 also needed a fuel pump).