Topic: Headlight No Worky...

[EverettShadowbrook]

Ok. I've got a CB750 and the headlight doesn't work. I have already ruled out the following. Bulb is good. Fuse is good. Wiring is correct and connected (both in the headlight bucket and the switch).

Any other ideas? As always thanks for everyone's help.

[Duke McDukiedook]

Fuse might not be good even though it appears that way.
Try a new one and see if that does anything.

[EverettShadowbrook]

I will check that. Thanks. Anyone else want to add their two cents? I think it is illegal to ride in CA without a headlight on and I really want to rip the PCH this weekend.

[TwoTired]

What year 750 should we refer to as an appropriate wiring diagram?

If the battery is charged, the wiring is good, the switches good, the bulb is good, and the fuse is good, you have a working headlight.  You are certainly mistaken on one of these mentioned points.

Alternately, you haven't paid the proper homage to the Tron god, he is super pi$$ed at you, and nothing you do short of laying the entrails of your favorite pet on the headlight at moonrise will restore you in good graces.

Personally, I have never needed to sacrifice a pet.

[EverettShadowbrook]

76' CB 750

Battery is good. New.
Fuse looks good - still have to check with new fuse
Bulb is good

Not sure to tell if the switch is good. wiring is connected. What other elements can make the switch faulty?

Who's tron?

Thanks again...

[billybobobrain]

Get a meter or light stick thing the kind that hooks to ground and has a sharp point and light take apart your headlight bucket to see wires. poke the sharp end into the black wire going to the right controll if you have power. move to the blue and white wire coming out of the right controll if you do not have power you are not making connection in the control... the bottom line is power = light if you have no power you have no light. the wiring for most (all the Honda mc's I've worked on) black is power, green is ground  blue and white coming from right control are high and low. if you don't have power at any point in the chain move down until you do, if you have power move up until you don't in either case the problem will be between the point were you do and the point were you don't... good luck.

If you have a good meter you should check for contenuity from ground. If you don't have that you wont have light either.

[TwoTired]

Tron is the deity of electrical flow, and is the only entity that can make electrical things not obey the laws of physics when they should.


Switches are faulty when they don't make electrical contact when the "ON" position is selected.   Damaged points, dirt, corrosion, improper assembly, misplaced hatchet strikes, etc.

Have you any familiarity with multimeters?

[EverettShadowbrook]

No. Not familiar with multimeters. I guess you could say I'm an electrical idiot.

Also, my headlight switch doesn't have an on/off option, just high and low. Is that normal for my year cb?

[Steve F]

Do you have a U.S. version of this bike where the headlight is on when the key is on?  If so, the headlight circuit runs through the starter button, so when you push the starter button, the headlight goes out while the starter is cranking, and comes back on when the button is released.  I'm assuming that your bike does this, and you don't have a headlight "on" switch.  Check that the button and switch case in the right control isn't in a bunch of pieces.  They're cheap plastic and just fall apart over the years.

[Lights Out]

I was wondering why I couldn't find the switch? thanks!

Do you have a U.S. version of this bike where the headlight is on when the key is on?  If so, the headlight circuit runs through the starter button, so when you push the starter button, the headlight goes out while the starter is cranking, and comes back on when the button is released.  I'm assuming that your bike does this, and you don't have a headlight "on" switch.  Check that the button and switch case in the right control isn't in a bunch of pieces.  They're cheap plastic and just fall apart over the years.

[EverettShadowbrook]

Ahh. I see. Yes the starter button was in a bunch of pieces when I took the right control assembly apart. I completely removed the switch ( it is now kick start only). Is there a way to bypass this so my headlight will work without the starter switch?

[burmashave]

No. Not familiar with multimeters. I guess you could say I'm an electrical idiot.

Also, my headlight switch doesn't have an on/off option, just high and low. Is that normal for my year cb?

Hey Everett, there's a FAQ about electrical troubleshooting in the Electrics FAQ. Part of it is about selecting and using a multimeter (MM). As I recall, one of the links goes to an interactive tutorial that simulates use of a MM.

[burmashave]

What year 750 should we refer to as an appropriate wiring diagram?

If the battery is charged, the wiring is good, the switches good, the bulb is good, and the fuse is good, you have a working headlight.  You are certainly mistaken on one of these mentioned points.

Alternately, you haven't paid the proper homage to the Tron god, he is super pi$$ed at you, and nothing you do short of laying the entrails of your favorite pet on the headlight at moonrise will restore you in good graces.

Personally, I have never needed to sacrifice a pet.

Ha, ha, ha.

I worry. Your statement implies such sacrifices may at some time be necessary. There is also the approach, taken by myself on more than one occasion, of throwing chicken bones in the air to foretell the point of failure.

[EverettShadowbrook]

Not having a starter switch... is there any way to bypass the wiring around this switch so my headlight will work?

[TwoTired]

You need to connect the Blk/Red wire going to the fuse to the BLK wire.  I think you can find both of these in the headlight bucket, assuming you still have one of those.

However, the headlight will stay on during electric start and drain your battery faster, as well as lower the voltage getting to the coils.  Don't be surprised if starting operation is less crisp.

[EverettShadowbrook]

Nice. Now we are getting somewhere.

HaHa. Yes I am missing a few important elements (ie: electric start) but it is a work in progress.

Thanks. I will try rewiring

[jtb]

Tron is the deity of electrical flow, and is the only entity that can make electrical things not obey the laws of physics when they should.

There are so many Tron brothers...  which one is King?   

[TwoTired]

Tron is the deity of electrical flow, and is the only entity that can make electrical things not obey the laws of physics when they should.

There are so many Tron brothers...  which one is King?   

There can be only one.  There are many that call themselves Jesus.  Only one has thorn scars in the scalp, a gash it his side, and holes in feet and hands.

BTW, watch it.  Tron doesn't take kindly to usurpers or those that stray from the one true Tron.  If you find yourself in the dark, don't expect your flashlight to help you.


 

[burmashave]

Who is this Tron that he should claim rule over us? Can the flashlight light our path if batteries are sold separately? Can the microwave oven cook a hotdog if the grid is down? The venerable Tron may be omnipresent; however, he is neither omniscient nor omnipotent.

[billybobobrain]

Just be careful he doesn't deres you!