Re: What's the bare minimum to make 954 run
Trimmed the wiring harness.
Do you have a Service manual for the 954? You'll get the wiring diagram in there. Or if you search here there's a dedicated thread to wiring harnesses.
You'll need the 954's ECU, CDI, Reg/rec, fuel pump, fpr to name a few things.
I don't know specifically, but there are things about the ignition that must properly function for the ECU to let the engine fire up.
Go the the fuel management section 6 in the Honda Svc Manual, read thru all the code faults, and I believe that will answer a lot of questions for you.