Wiring Issues

The re-build of my 1981 XJ750 continues. Up to wiring stage. Now have the correct loom and handlebar switches to match (thanks to advice from this forum). Have attached all connectors, checked operation of all handlebar switches. Powered her up and almost everything works. NB: have the Antari in place for the moment.
No neutral light and wouldn’t crank. Pulled the starter cut out relay and jumped the two R/W wires. She cranked over twice and that’s it. Won’t do it again.
Have checked fuses and replaced solenoid. All good. HELP

 

Battery charged?

You can test the starter by shorting across the two large terminals on the starter solenoid with and old screwdriver. The starter should spin when those are shorted, just be sure the bike is in neutral and / or on the center stand.

If that works you can apply 12V to the starter solenoid two terminal pigtail connector. That should energize the solenoid and apply 12V to the starter making it turn

If that works then it is simply a starter switch issue or the wiring to the solenoid pigtail since you have the starter safety circuit defeated with the jumper

 

Thanks for the reply. Followed your instructions and it came down to faulty starter switch.
Now that she cranks, I tested compression and
discovered blown head gasket.
Ohhh dear. She wasn’t far from riding.
Thanks again

 

Are you sure it is the gasket? What are the compression figures? Are the valve clearances in spec? Are the piston rings gummed up?

 

Cold compression test. 120 psi on 3 and 4.
60 psi on 1 and 2. Also prior to cleaning the motor up, there appeared to be bad seepage between 1 and 2.