Topic: no brake light or electric start

[78whiteorbs]

Just got my 78 cb750 back online and went for a shake down ride. Ran nice besides needing new fork seals.

Anyhow father inlaw came by later and went to fire it up and the starter switch gave nothing! Thought maybe somehow the battery was drained so I tried the electric leg and easy as you please she roared to life. Killed it and tried starter again and nothing , no clicking or nothing. Took a screw driver and jumped the posts on the solenoid and the starter engaged and she started right up..... So bad button or bad solenoid?? I dunno ...

also trying to wire new brake light and it seems simple enough right > ? ha
well am getting nothing. Volt meter shows that the green and yellow is hot (4 volts)
and when I press the brake pedal it jumps to 10  so seems in order but no lights? tried the stock one back and same thing , nada... and ideas?

[HondaMan]

Just got my 78 cb750 back online and went for a shake down ride. Ran nice besides needing new fork seals.

Anyhow father inlaw came by later and went to fire it up and the starter switch gave nothing! Thought maybe somehow the battery was drained so I tried the electric leg and easy as you please she roared to life. Killed it and tried starter again and nothing , no clicking or nothing. Took a screw driver and jumped the posts on the solenoid and the starter engaged and she started right up..... So bad button or bad solenoid?? I dunno ...

also trying to wire new brake light and it seems simple enough right > ? ha
well am getting nothing. Volt meter shows that the green and yellow is hot (4 volts)
and when I press the brake pedal it jumps to 10  so seems in order but no lights? tried the stock one back and same thing , nada... and ideas?

It sounds like your rear light is missing a ground. Many aftermarket ones are, so you have to make your own ground to the socket.

The start solenoid: check across the 2 small wires at the solenoid with a voltmeter. Key on, press the Start button, see if 12 volts appears.

If not, and if your bike is post-1972, you may have a 'safety module'. This will require that either you have a [working] clutch switch engaged (i.e., pull in the clutch), or the bike must be in Neutral and the Neutral light actually works, before the solenoid is allowed to switch ON.

[78whiteorbs]

thanks hondaman-

I tried pulling in the clutch and it made no diffrerence. Positive it was in neutral as I could kickstart it . It worked fine from the button for several monthesprior to shakedown ride. I might try rocking it back and forth and click it in neutral and see if that makes a difference. I deleted the stock gauges but I know sometimes when you click a bike in neutral the light doesnt come on if you dont hit the sweet spot.

With the brake light I got one from Lowbrow customs and it worked fine when I tested it when it arrived. It grounds through the mount and there is good solid frame contact . I even tried hooking up the stock light and got nothing which is weird.  Worked fine too. Not getting any voltage from the brown wire but am from the green/yellow and when i press the brake pedal the voltage increases.  I did delete the key and install a toggle switch  for the ignition so I am thinking the brown wire is the running light and has to be wired directly. Not sure if I did that 

UPDATE- Think that I might have found the brake light boggle. After reading some old posts when I installed the toggle its just connecting the red and black wires when in the on position and disconnecting them when in the off. I read here : http://forums.sohc4.net/index.php?topic=13387.0  that you have to connect the brown and brown and white wires together as well for tail light. If this corrects it , would be cool. At the moment the tail/brake light is the only thing keeping me off the road.