New owner, headlight doesn't work

Hey, all. I've been lurking for about 6 months now. My bike is an '84 VF700F, it's only problem is that the headlight doesn't. I've cleaned electrical contacts everywhere I could find them, squirted some cleaner into the starter button (which was stuck just far enough out to not engage the starter, but now is free), and installed a new bulb. My multitester shows 14-15 volts at the light, and continuity with the frame from both grounds.

Suggestions from VFRD pointed me at the starter button. Does anyone have any other suggestions? Warm weather is coming and I need a headlight to be legal here.

 

Well if you have power to the light and confirmed a good ground then it has to be a bad bulb or connection at the bulb....

 

Just as an FYI, when you hit the starter button, the headlight will go out to allow the full power of the battery to start the bike.

It's gotta be the bulb. Have you tested it for continuity?

 

I never even THOUGHT about testing the bulb. Dang thing's brand new!

I'll check it as soon as I get home tonight.

 

Touch the bulb terminals to a 9V battery to test them. It's not a lot of amperage, but enough to illuminate the bulb.

If it's an H4 replacement bulb, don't you need an adapter to run it in the Honda housing???

 

Adapter? No, I don't think so...

The new bulb fit right in to the housing and the electrics plugged right in. All the parts sources I can find reference it as an H4.

 

check contacts and wires in "start" push-button, also check for broken solder connections there.

OR you could set up a jumper wire at the plug-in connector for right handlebar switch ( after referencing wiring diagram) to remedy the problem IF the problem is in that switch.

 

Another strong case for a bad headlight relay. I'm not familiar with the early bikes, but if the starter button turns off the headlight, it does it by de-energizing the headlight relay. Look for the relay.


Lane

 

Dug through the electickle diagram and played with the multimeter; where there should be connectivity through the starter button, the meter remains silent. I can't see how to get in there without breaking it, so I think I'll just install a toggle switch to bypass it.

Just have to remember to turn it ON after starting the engine...

 

Crack open the control pod and spray the heck out of it with electronics cleaner. Close it back up and move all the switches back and forth about 20 times. See if that fixes it.

 

(there is no headlight relay on this bike..)

there is profound life-philosohpy to be derived from this difficulty:

"IF you can't fix a problem, you still may be able to wire around it."

 

Well squirrelman, I think you just gave me a new sigline.

Mason45, I did that; still no worky.

I ordered the switch this evening, a DPDT on-momentary, and a safety cover for it. It'll take over the job from the starter button. I'm thinking of mounting it below and to the right of the instrument pod.

When I get it done, I'll post a pic.

 

Well you must not have 12volts at the light or a good ground otherwise your light would work if you had a good bulb and a good connection at the bulb. Adding another switch and wiring around things like a backyard mechanic fixes nothing but makes a band aide out of your bike thats just waiting to catch fire....

 

If you are testing the voltage with the wires off of the light bulb, you should use a test light. If you have a high resistance in somewhere between the fuse panel and the headlight, it will still show battery voltage when the plug is off of the bulb (open circuit will always show highest potential regardless of condition) when using a meter. Use a test light and see if it lights up. Do not be surprised when it does not light up. You have a bad connection somewhere in the harness for the headlight, maybe even in the fuse panel.

 

slovfr, since when do band-aids catch fire??>?>

some must use JB Weld, duct tape, and salvaged odsandends because new Honda replacement parts are too expensive.

As for backyards, they're as good a place to fix a Honda as any dealer's shop, IMO.....unless it's raining.

He's using a fuse, i presume, in the new wiring.

IF replaced by new parts those handlebar switch units run about $70 i'm guessing, while the new switch he installed will run around $4 or so.....


man's gotta do what a man's gotta do to fix the problem at hand....

 

I've had the same problem with my VF 500. tap up on the control box switch on your handle bars . it worked for me.

 

After 25 years in the repair field I can attest to the fact that if the original problem is not fixed and a work around is used it leads to further problems. What if its not working because of a short to ground? or high resistance in a wiring harness? High resistance means heat means possible fire may happen. Have you seen some of the pics of the VFR regulator and stator wires when they have too much resistance? It brings on a whole new meaning of owning a RED bike......

But do as you wish, just one mans opinion ..... but then again I've owned lots of Fiats so Im a bit wiring paranoid

 

Most would agree that electrical issues are the most common Honda problem.....

the low end Italian cars used Magnetti Marelli, the better (my Alfa) used German Bosch stuff, and that solved most (not all) electrical probs.......

While i worked as a cycle mechanic at a small dealer i did burn as bike totally down to the ground, but it was fuel-related, not electrical, and it was only an old:yell: Yamaha Virago anyway, so no big deal.........as everyone knows, s8it happens!

 

If you read my earlier post, you will see that I performed a connectivity test straight out of the service manual for the starter switch. The test failed when the switch was in the normal (out) position. Not just once, but repeatedly. The circuit that is broken is the one that controls when the headlight is on (normally) or off (when starting). If the headlight is still not working after the new switch is installed, I'll start digging into voltages and resistance.

But having found one failed component in the circuit, I have to replace it with SOMETHING.

I will be using a 10a fuse in the line; the fuse in the fusebox. All I'm doing is replacing the original switch with a new one; all wiring will remain the same other than going to the new switch. I'm not sure how this will convert my admittedly red bike into a fireball. If it does, I will hang my head in shame and repent. :yield: Until then, if I want to ride I have to have a headlight.

replacement control box = $88

new switch = $5.51 + I got a mil-spec cover for it which was twice as expensive as the switch. So I'm out a grand total of $16. With a little bit of work and some thought I will have saved $72; almost enough for new fork springs!

 

Having owned and fixed more than one Brit, Italian and German bike one lesson on electrical stuff I learned the hard way is that in a sequence of say three components, the middle one if replaced dumps bad karma on the rest.

May I suggest downloading a factory manual on your bike and going through the entire switch to bulb to ground circuit.

BTW, Honda didn't invent "The Prince of Darkness." That was Lucas..