Motorcycle Questions? Ask a Mechanic.
Hi and welcome to JustAnswer,Thank you for the question and your patience. Should you still need assistance for information purposes only...Initially and if have not been tried; inspect the battery, its ground lines and/or check/clean the battery cables + terminals, connectors and wiring as a preliminary consideration. Have the battery externally charged and then LOAD TESTed (even if new/charged and just for the purpose of eliminating it as a suspect).
Try with the clutch lever pulled in.
Still, proposed other tries and re-checks (if have not been done) would be to determine the presence and consistency of the voltages at the different wires of the starter relay:
Do the the above voltage checks twice; once with just the ignition switch on and the second when attempting to start.
Appreciate your kind understanding and patience as I am currently mobile with sluggish Internet hence delays.
The Reverse Inhibitor Unit as its name implies would not allow the starter relay to engage should the Honda be in reverse when attempting to start. Its built-in electronics includes a diode that may have failed.
As a test, disconnect the starter relay's yellow/green wire from the Reverse Inhibitor Unit and temporarily connect this wire it directly to ground and/or a green wire.
Appreciate the post back.
Have you tried directly IGN+12 on the yellow/red wire and a ground connection to the yellow/green ?
If the starter relay are directly provided with +12V and ground from a fully charged/good battery, then even if the starter button is not pressed, it should engage (click) and the starter motor should spin.
The reverse inhibitor has already been taken out of the equation when the yellow/green was directly (even if temporarily) connected to the ground.
The reverse inhibitor if connected and working as expected internally grounds the yellow/green wire if the transmission is in neutral and/or not in reverse.
The starter motor is powered when the starter relay engages/clicks. This happens when the yellow/red wire receives an IGN+12V either directly (as proposed above) or through the START switch. The starter relay's yellow/green wire should be tied to ground either by the reverse inhibitor if working normally or directly as likewise proposed above for test purposes.
Either way, if it clicks and the battery is good, then the starter motor should turn.
Is there an audible click from the starter relay either through the START switch or directly wired?