Topic: Starter motor won't turn over

[katman]

Happy Thanksgiving everyone.
Allright my CB750K(77 model) is back together. Rolled it out this morning while my turkey is smoking.
Hit the starter, the headlight dims and nothing. All lights and signals work. Checked cable connection at battery and soleniod
for tightness. My walmart battery charger say battery is charged. Were do I need to look next.

[Black 750K8]

See if it will start with kicker " the headlight dims and nothing" Does this mean it will not turn over or it will not start? Check for voltage on the small wire at the solenoid.

[katman]

Starter motor does not  turn over at all. No clicking at the solenoid either.

[Stev-o]

Do you have a voltmeter to check your battery?

Jump the solenoid with a screwdriver to test your battery and starter.

[katman]

Okay, jumped the solenoid with a screw driver and the starter turns the engine over. I did notice when pressing the starter button headlight goes completely out. Battery maybe?

[Black 750K8]

Okay, jumped the solenoid with a screw driver and the starter turns the engine over. I did notice when pressing the starter button headlight goes completely out. Battery maybe?

It is normal for the head light to go out. Check the start button it still could be the battery. Try jumper cables from your car with the car engine NOT running and make sure you don't hook the cables up backwards or you could fry the rectifier.

[katman]

Battery did have a low cell. Went ahead and put in a new one. Like I said, the starter and motor do spin when arcing soleniod
with a screwdriver. I am suspecting the push button switch. Is there any way to test it were it plugs into the plug in headlight.
and which wire do I test.
Thanks

[Kevin D]

Here is a k7 wiring diagram:

http://manuals.sohc4.net/CB750K/CB750_K7_WD.pdf

Do you have it in neutral? clutch pulled in?
Does the neutral light work?

Looks like yellow/red should have +12v when pressing the button.
 

[katman]

Bike is in neutral. Never had to pull in the clutch before. 77k model

[Don R]

The 77 has the plastic start switch that is a known failure point. The plastic crumbles. Check the small wire to the solenoid to see it it gets voltage when the start button is pressed. You may need a new right control. I temporarily wired a double pole switch on my 76 until I could get a new control.  Find that wire and follow it into the headlight bucket, it connects there and then goes up the handlebar to the start button. I believe on a 77 the wires are outside the handlebars.

[katman]

Okay, using a test light I have power coming in and going out of yellow and red wire at the plug in headlight bucket when starter
button is pressed. were should I look next.

[Vinhead1957]

Starter solenoid

[Patrick]

The safety circuit on a '77 works b y depriving the starter circuit of  ground. Run a different ground wire to your solenoid. If your starter works, then the problem is in the safety circuit, If it still doesn't work. look at cleaning your starter button.

Patrick

[katman]

Success! Cleaned starter button, still nothing. Turned out to be the green and red wire at the solenoid, the male end
was kind of dirty. brightened it up and plugged it back in and problem solved! Thanks guys.