Topic: No lights!

[Vintagewannabe]

Hello all, this will be my first post as I recently got this bike. It is a 76 cb550. I am having some strange problems with my lights. I have my neutral and oil light on the dash, but no headlight, tail light, or brake light. The bike is in very nice condition, and very close to stock. The bike had an aftermarket set of black bars, and we put a set of factory chrome bars on, and ran the wiring for the controls back through the inside of the bars. When wiring back up, I matched all the colors on the connections under the tank. Now I have no lights. I went back over my connections multiple times, and it all looks good. My main fuse looks like it has previously gotten hot, but not blown. I have power to the connections under the tank, but not at the headlight. Another strange thing, is that the white wire that was routed to the high beams, was connected to the brown wire in the bucket, which the wiring diagram I have says is not used. The male end of the white wire was taped up. I cannot figure out what is going on, is there any common issue?

[grcamna2]

Welcome to the forum. 
I'm good with wiring,when it's right in front of me..;someone else will help.

[CycleRanger]

Hello!
That brown wire that is unused is for a parking light that was used on Euro bikes but not in the US.
If everything was working before you changed the bars I'd look for a loose ground wire somewhere.

[HondaMan]

The middle fuse in the fuseholder powers the headlight (and sometimes taillight): check that one.
I make a modern blade-style fuseholder for these bikes: the old SFE type fuses that were used in them haven't been manufactured since the 1990s (1996, to be exact...). Trying to use an AGC type fuse will work while the bike is stationary, but when rolling along they will break and look like they "blew" because they get soft while carrying current. PM me for details.

(Edited 8/16 added 'sometimes').

The 550F and 550K wirings are different: which is yours?

[Don R]

 Also the fuses can appear to be fine but get burned off in the cap where you can't see it. Check with a test light.

[scottly]

If everything worked properly before changing the handlebars, something didn't get connected back up correctly. The white wire from the dimmer switch should connect to the white wire from the headlight. The blue wire from the dimmer switch connects to the blue wire from the headlight, and a solid green wire from the harness should connect to the green wire from the headlight.(This assumes a stock wiring harness and switches. Some aftermarket parts don't follow the stock colors.)
The headlight and taillight each have their own fuse, and the brake light is powered by the main fuse. Does the brake light work when you use the rear brake?

[bryanj]

Electrics is easy with a diagram when sat in front of the bike but impossible to do long distance over the internet.
The only thing i can suggest is get the EXACT wiring diagram for your year and model and carfully study that whilst doing the connections, by the way all bets are off if ANY of the parts are aftermarket

[scottly]

Electrics is easy with a diagram when sat in front of the bike but impossible to do long distance over the internet.

It was a hell of a lot harder back in the day when I only had a telephone!! Nowadays the internet makes things so much easier, with pictures and even videos.
Of course, I can see how someone that never used a strobe to check timing, or bothered to use feeler gauges when setting tappets would have problems adapting to modern technologies.

[HondaMan]

Of course, I can see how someone that never used a strobe to check timing, or bothered to use feeler gauges when setting tappets would have problems adapting to modern technologies.

Hey! Me and my old SuperHawk resemble that remark!

[scottly]

Of course, I can see how someone that never used a strobe to check timing, or bothered to use feeler gauges when setting tappets would have problems adapting to modern technologies.

Hey! Me and my old SuperHawk resemble that remark!

You didn't have the feeler gauge that came in the factory tool kit, or didn't bother to use it?
I never used a timing strobe on my 1966 C200 90, but I didn't own one of my own until 1972.

[Vintagewannabe]

I really appreciate all of the responses. All of my fuses are good and I am getting power under the tank where it connects to the controls. I have power going to and feom all wires in the fuse box.

[Bodi]

Definitely get an actual Honda wiring diagram for your year and model, there's one in the service manual if you can download one. The Haynes etc ones are not 100% accurate and skip some "minor" details that can drive you crazy when tracking down problems. The "colored" ones are the worst in my experience, OK for a general idea of the circuits but not good for troubleshooting oddball electrical issues.
Some 1976 models (and other years after 1972 I believe when the law came in) had to have always-on headlights for USA and Canada models. The main harness is set up for a switchpod headlight on/off switch though, and the always on pods don't have it or the wires for it. Honda added a weird jumper stuck into the right switchpod wiring sleeve (just loose, nothing holding it in). This connects the black wire in the harness end to a brown/black wire there - power to the HL fuse - replacing the headlight on/off switch. This jumper (black wire and a brown/black wire about 10 inches long, spliced together at one end with bullets at the other ends) tends to fall out of the sleeve and be a "what the heck is that?" item in the garage. OEM replacement switchpods, regardless of the model they're for, did not come with that jumper.
So check if you have power at the HL fuse. If not, see if that main harness brown/black wire is connected where the pods etc connect. You need a male to female bullet jumper. As a rule female harness bullets have power, males go to power something - avoiding sparks and smoke if a male touches metal.
I won't go into the bizarro wiring for the parking lighting. Except that the brown wire is for a small parking bulb in the headlight for some markets, aftermarket H4 headlights often have this extra bulb. Key in park just leaves the tail light and that potential front bulb lit. I have never used it and nobody I've asked has either, you would just come back to a dead battery IMO.

Brake light is really odd to not work. The brake switches (mechanical rear and hydraulic front) connect to switched power, the black wire, then to the stop light on a green/yellow wire. It should work whenever the key switch is in run.

Hondaman's fuseblock is a really good upgrade. The original, after almost 50 years, is not in good condition now because the plating on the contacts has unavoidably corroded away. That starts a chain of events where fuseclip to fuse connections heat up, corrode faster, heat up more... then melt either one or both of the fuse internal connections or the solder connections from the harness wires to the fuseclips.

[HondaMan]

Power sources:
The Blk/Red wire from the START button powers the Headlight fuse in the fuseblock, which then powers the Brn/Red wire that goes back to the left-hand HI/LO switch, where it is then distributed into the other Brn/this and Brn/that wires to the other lights.

Something important to know: many of the START buttons have gone bad now, because they have to carry the whole lighting system when in the NOT PRESSED state. This NOT PRESSED state has very light spring pressure in teh 50-year-old switch, now, and the once-pristine contacts in the pushbutton are not pristine anymore. So, you might try disconnecting the Blk/Red wire from the START button and temporarily jumper it to the BLACK wire somewhere to see if the lights come on. If so, the START button needs to be replaced.

Or: you can ditch this subsystem in another way, which I have called the "Start Switch Saver" relay kit: this situation happens often on the 750 because of someone installing too-hot headlights (like 80w or even 100w headlights) which melt the switch contacts. They can be bypassed, or the Relay Kit can be substituted instead. Keep in mind: if this bike has a headlight of more than 45w HI beam, the alternator cannot supply enough power for it to charge the battery when riding in city traffic: a "hotter" headlight also damages the START button in the non-pressed condition, burning its contacts.

[Vintagewannabe]

Well it looks like we found the problem. We started checking through the grounds since the problem could be intermittent at times. Looks like the one under the tank shorted and burnt up into the harness

[HondaMan]

This suggests that somewhere there may be a powered wire plugged into a Green ground? It's odd for a ground wire to melt back like that otherwise.

Did it damage other wires (by being too hot, too close to them)?

When pulling old wires thru handlebars that are not nicely finished inside (Honda went to a lot of trouble to make sure their OEM handlebars had not sharp edges inside them) it is extremely easy to nick the insulation on the wires. This, then, can cause all sorts of odd shorts-to-ground, drawing lots of current and making things melt like that.

Check for someplace where a Brown (or Brown/[stripe]) wire may have a nick that touches inside the new handlebars. That could put both the Ignition power and the lighting power onto the same ground, which could then cause an overload and heating like you've got there.

The Green wire(s) can normally touch ground anywhere without any troubles: Green IS ground in these bikes. The overload issues that cause melting like this come from having too many circuits feeding into a single Green. This can only happen in a normally-wired bike if there is an inadvertent short-to-ground somewhere.

[scottly]

The most common cause of a melted ground wire is from connecting the battery backwards, which turns the rectifier into a short from the battery plus terminal to ground, through the green wire, melting it. This can also damage the rectifier. As this produces smoke, as well as the smell of burning plastic, and you didn't report anything like that, we can assume the damage was done by a Previous Owner.

[bryanj]

The more common cause for that wire melting is not cleaning paint/powdercoat from both side of the LH rear engine mounting plate where it connects to engine case and ground wire to battery the all the starter current goes to ground via that small green wire at the coils which gets super hot and melts

[Vintagewannabe]

These are some good things to check for. The coating looked good when I pulled the harness back out of the bars before I found that ground, but I'll make sure none of the hots have connection to ground.

[newday777]

Welcome to the forum Vintagewannabe
So what's your plan now? Replace the harness or repair it(solder/heatshrink new wires in, ?)?

Is this bike a K model or the F(Supersport), you didn't specify it in your 1st post other than it's a 550. Very important as there are different parts between them.

Go to the new members section and introduce yourself and your bike. Pictures are always welcome. We like pictures.

[Vintagewannabe]

My plan is to replace the harness. And the bike is an F model.