Topic: Trying to figure the wiring out.

[ozi]

Hello, I am rebuilding a '75 Honda CB750 (mostly a '75, I do have some '78 parts) and I'm having trouble with the wiring. I completely rebuilt the engine, powder coated the frame , and I purchased a new wiring harness. I am not very good with electricity to begin with and now I'm running into problems.

I didn't have a starter switch, so I bought a new one. It has the starter button, the lights switch, and the kill switch.

I didn't have an ignition switch, so I bought a new one.

I'm using an old starter motor safety unit, rectifier, regulator, oil pressure switch, and pretty much everything else is old.

The issue at hand is low(0.03V)/no voltage to the starter solenoid when the starter button is pressed, obviously, no clicking at all. Continuity is present when the button is pressed but there is not nearly enough voltage to engage the starter solenoid.

I tested the starter solenoid directly to a battery and it works. I bypassed everything and tested the starter motor, it works well. The fuses were swapped out with new fuses and they are still functional.

The oil light and the neutral light turn on as soon as the key is position 1, and turn off in position 2.  I am a newbie with motorcycles (never having ridden one myself) but I have some experience with engines so please excuse me if I'm making an ignorant mistake... for I am ignorant with motorcycles.

Any help is greatly appreciated.

[ozi]

Also forgot to mention, I am using my car batter at the moment. It is 100% fully functional and charged so it is not the issue.

[scottly]

I'm using an old starter motor safety unit, rectifier, regulator, oil pressure switch, and pretty much everything else is old.

The issue at hand is low(0.03V)/no voltage to the starter solenoid when the starter button is pressed, obviously, no clicking at all. Continuity is present when the button is pressed but there is not nearly enough voltage to engage the starter solenoid.

The starter button applies a ground, via the safety unit, to the yellow/red solenoid wire. The other wire is fed 12v whenever the ignition switch is on.

[ozi]

Scottly, thank you for your description. Simplifying it really helped me ensure that everything was going okay. It turns out that I needed to have the clutch engaged when trying to start it. Everything was wired correctly but the clutch wasn't engaged. I'm going to file this under "I've never ridden a motorcycle and I have no idea what I'm doing".

The starter motor is turning but the bike hasn't turned over yet. I'm off to check on the spark.

Thanks for the help!

[scottly]

It turns out that I needed to have the clutch engaged when trying to start it. Everything was wired correctly but the clutch wasn't engaged.
The starter motor is turning but the bike hasn't turned over yet. I'm off to check on the spark.

Thanks for the help!

The starter should also turn when the transmission is in neutral.