Maritime
Over 10,000 Posts
OK, that is diff from the OEM Honda. Was there instructions? The wire labeled start is the signal wire to the solenoid I would assume, not the hot wire from the battery, that would be thicker. So you should have a hot wire from battery to solenoid, then a wire to starter on the big bolt terminals, then the signal wire to switch that goes to ground after pushed and another for maybe the kill switch, not sure on CB400 but most Honda's are the same. Put a meter on the blue and black from the button and test for continuity, should be none when open and 100% When pushed. or use a battery and test light and make a circuit, light off when not pushed, on when pushed. If that checks out, it isn't the button, but something up with the signal side of the solenoid, it may be bad if original. If you jumped the thing with a screw driver and it fired the power it good to it. Does it click at all? You are not getting the signal from the button to tell the solenoid to close, it's a big electromagnet that when the signal goes to it, the magnets pull together and complete the power to the starter, let go and the magnets repel. Polarity I think is important so if the signal wires are reversed they never attract.
