TOPIC:

The headlight and steering stem area is prone to shorts, as turning the handle bars back and forth move a lot of wires.

I had a problem there, with one of the white plugs touching the headlight shell. The backside of the white plug had one of the metal plugs sticking out a bit, causing a short.

I needed to do this for my 77 650. Started out a major pain in the ass, but ended up being a very rewarding experience. I ended up changing out the core wiring, and needed to fix some wires in it as well. These bikes are ~30 years old, the wiring just gets tired is all.

I found an in color wiring diagram on site here, Thankfully. It was better than the diagram in my Clymer manual (which is nearly useless being solely black and white).

I believe I found the same one for your bike on this page here. You do need to download it to expand it enough to read the fine print, otherwise just viewing it is ok.

kzrider.com/index.php?option=com_docman&...w&gid=126&Itemid=108

The multi-meter can be one from Radio Shack. I got mine for 20 dollars and have used it for thousands of dollars in my opinion.

Wiring is simple. the stuff flows from battery post to battery post. On the diagram, you can figure out which wires could cause the problems you are experiencing. (Obviously you are not really concerned with the wires that supply power to your dash lights, look for ignition related wires, fuse blacks, key switches and main power buses). Check the diagram for wire color, remove your tank and side panels and go find the circuit on your bike.

Go end to end. If it has continuity, jostle the wires and try it again. You want to be sure to find the broken wires that are intermittently fine and sometimes broken. Start at one end and check a wire at points further and further up the line 'till you find the opens (breaks). Cross the fuses (check across, looking for zero ohms 'good' not zero load 'bad'). Cross the bundled wire connecting plugs. Cross switches in both on and off positions. Close/open the key. Root out the electrical gremlins.

If you find something suspect, be specific with the wire's color stripes and such, and where they run from and to, and ask online here. Some circuit's wires will have inherent resistance, and there are helpful people here with deep knowledge of these numbers.

My bike had a power wire that had burned insulation off of adjacent wires. It was really odd when it rained. All sorts of weird shif would happen, including engine dying.

Have fun wid'is. It is worth it in the end.

Oh yeah, check the ground from the battery.

I would go post to post on the disconnected battery wires and check ohms too.

I would check that wire coming from the positive battery terminal, and follow it to your ignition switch.

How is the regulator?

It could be that you have a short that is dumping power to ground.

Just some thoughts.

I've got a multimeter and the wiring diagram but I'm looking for tips and suggestions where to look first which many of you have already provided. The kill switch is definitely not in the off position (I found this out the hard way once after pushing the bike home and then couldn't find out what was wrong). But, let's say the switch is defective........would that render all circuitry inoperable? I mean, shouldn't the lights still work? Even when I turn the key to "acc" I still get nothing. If I had a short in the wiring wouldn't a fuse blow? The regulator/rectifier is the original part but if that were defective shouldn't the lights work? I'm inclined to think that there is a major break in the ground or hot lead.

I'ts been a long time since I did this electrical stuff. I should set the multimeter to how many ohms when doing the continuity check? And when I cross wires it should read 0, if it reads 1 or -1 that means the circuit is open..........right?

With wire continuity, it seems to me that the range doesn't really matter. set it for a high setting.

If a wire is good, then there should be zero ohms. If it jumps all over the place, it probably means that the leads are skipping, or the contact is dirty. To me, a very very small and steady amount of resistance might not be such a bad thing (any opinion on this guys?).

On my meter at rest set to ohms, it reads '0L' for zero load. If this shows while testing a wire, it is an indication of a wire, or circuit, that is not allowing current through. An open. Ergo faulty, bad, no bueno....

As far as shorted wires, if they are shorted BEFORE the fuse, then the fuse never carries the current, and therefore doesn't blow. If you have a short in the right place, it is possible for the short to render the entire electrical system inoperable. For instance, if the main power wire left the battery and shorted to the frame. No fuse would blow. I doubt that is your problem though.

Does your battery hold current?
what is the resistance across the disconnected battery leads with the key off?

Go to the diagram and follow the path from the battery through the headlight. Get the color of the wires noted and go and find them on your bike. Then test the circuit.

I am going to look at the diagram for my bike. BRB

Ok On MY bike.....

There is a power wire that goes from the battery to the ignition switch. On yours, check to be sure that is in good shape, as well as the ignition switch. Do appropriate wires connect and disconnect when they should when the key is turned. These circuits are not complex, though they may seem that way at first. If something seems fishy, delve into it a bit 'til you discern that the part is bad, or you figure it out.

Then it looks as if there is a brown wire from the ignition switch that supplies power to a bunch of lights and a headlight switch that closes (good thing) when the key is set to on. Check that too at the switch. Check it back to the battery terminal. And check one wire end to the bike chassis to ensure that there is no short to ground where there shouldn't be. Wires should not flow to the chassis until they are supposed to. if the batter is disconnected and the positive terminal is not resting on the frame, then there should be no pathway to the chassis. If there is, find out where it is happening.

Then it heads to the fuse block. Then to the brights' switch, then to the head lamp, then to a common ground which goes back to the battery.

If the whole circuit checks with the battery terminals disconnected, the key on, and the switches in the correct configuration, without any breaks or shorts to ground prematurely, then congrats. You have just crossed off one possibility of a compromised circuit, and on to the next.

Don't be surprised if an appliance (lamp, coil, whatnot) reads some resistance. You are just checking the pathways at this point.

Somewhere in your search you are going to find a snafu or two or seven. Worn switch, broken wire, crispy wire (always fun) and you will fix them as they come.

You also need to realize there is a learning curve when dealing with this stuff. At first it seems daunting. Then you get creative/destructive with your exploratory methods. (I would sometimes push the lead's point through the insulation to get to a wire) and soon you will become pretty good with the stuff. You will also get your fingers dirty. That thirty year old black tape is nasty.

I hope I was of some help here.

Keep posting.

I suspect a bad ignition switch, or a burned power wire leading to the ignition switch btw....

I thought of this last night as well. By disconnected battery terminals that means the negative is disconnected from the block bolt as well. Don't give it a pathway to the chassis when testing.

The wiring schematic is like a simple maze. Bet you never thought the learning you got from those mazes you did in primary school would have ever been put to practical use. Treat 'em like one, there is a start and finish on them with some dead ends and some wrong ends (remember the crocodile that will eat you?). It is worst at first man, dive in ...

You can unplug the ignition harness and jump the white and brown wires. If it will start that way, then you need a new ignition. They are pretty cheap.

Well, here is what I found so far. The electrical circuits are not completely dead, there is some power flowing through. I found this out after removing the gas tank and the cover for the instrument panel lights. When I turned the key to "on" I saw a faint glow in the bulb for oil pressure. I started moving all of the wires to see if anything changed which it did not. I then hooked the battery charger up and the bulb now started to become brighter. The battery measured about 11.5 volts (without charger connected). I took the battery out and fully charged to about 12.4v. Reinstalled it and now get intermittent full power through the system. Sometimes the bulbs glow slightly and there is not enough juice for the lights to come on or for the horn to work. Then, sometimes I have full power.......I even started it but after about 30 seconds, the instrument bulb began to dim, the engine started to lose power and eventually stalled. What I found when checking voltage across the battery terminals is this:

- when the bulbs are dim, battery voltage only measures around 8v with key on. Voltage across the battery immediately started to drop from 11.5 even with the key "off".
- if I switch the key on and off until the bulbs are bright, power across the battery measures about 10.5v with key on and about 11.5 with the key off.

I tried jiggling the key on the ignition switch and the battery leads but this doesnt seem to change anything. I tried bending all the wires but that didn't seem to change anything. Sometimes the bulbs are dim and then suddenly become bright and vice-versa. I thought maybe the battery since it is 5 years old and one cell was pretty low on water before I fully chaged it. I tried shaking the battery with the key "on" but that doesn't seem to change the amount of juice flowing.

Any ideas?

I would check two things now. Buy a small hydrometer for bike batteries at the auto store and measure all six cells on a fully charged battery. If any are less then 100% buy a new battery, you certainly got your money's worth out of this one.. I think this battery has some bad cells that would allow a full charge but not really hold it for long.

Second, there should be a charge coming from the alternator to the rectifier-regulator, which in turn keeps the battery up to full power. Look in the book to see how to measure it for your model, I can't recall what year 650 you have as I type this, but the 77 is different from all the rest. One plastic multi-connection that seems to suffer corrosion a lot is between the regulator/rectifier unit (on 78 and later models) and the alternator. If this is corroded it won't keep the battery juiced up and lots of excess heat, melting the connection, don't ask how I know this.

Good luck and have fun

OKC