Headlight causing electrical problems?

Oops, was looking at West German model wiring diagram showing headlight on-off switch. :S

Regarding the voltage drop at headlight connector.

Maybe there's corrosion at a connector somewhere between fuse and headlight socket, or inside dimmer switch.

Just guessing.

Good Fortune!

[Click on image to enhance view.]

Stick with it it can be fixed.
Now armed with a fully charged battery/ or jumped from a car battery, 2 14 gauge test wires with clips, and hopefully a volt meter of some kind that you bought.
Lets start with the head light, key on headlight on, take 1 test wire and connect to the head light socket on the ground side and go directly back to the main frame or engine block/ bypassing the steering section. Brighter? No then remove it and then do the same for either the low or the high but go directly back to the battery post, brighter? Get my point its 1 or the other, bad ground or bad + connection. Ok so I assume that now you know which it is. Should be able to find where this needs to be fixed, If it is the + feed, have you checked you Ignition switch? You can bypass it with unplugging the connector and using 1 of the test leads make the connection that the switch normally does when on, follow this type of process with each and every switch in your circuit.
When you WG mod you masked over the real problem and is most likely still there. The Reg/Ret also needs power to operate, and it sound like you are losing your + at either the switch or possibly still a faulty connection.

Thanks for your help. Now all I need to do is buy a multimeter. To do that, I need to understand the differences between the ones that sell for 3.99, the ones that sell for 399.00, and the ones in between, and which ones are important to me in buying the one that does everything I need to find these problems at the lowest price.

Have extracted the following history from successive posts, believed significant to the voltage drop at headlight:

seanof30306 wrote:

...This past fall, we noticed there were only 8v at the headlight. The harness has been messed with a lot over the years, so we decided the next step was to replace the harness. I got two good harnesses from a couple of awesome kzrider.com members, and we've gone through both with a fine-toothed comb to come up with a single great harness, which we are in the process of installing....

Anyway, I'd also noticed over time that there were occasional electrical problems with the switches. Every now and then the horn doesn't work, every now and then the blinkers don't work, every now and the the bright lights don't come on, etc. A few minutes later, they're fine....

The last thing I want to look into are the handlebar switches, especially the one on the left-hand side, which controls the horn, turn signals, and bright lights. If they were available, I'd just buy new ones, but all you can get are Z1 switches, which are wired differently and don't have the emergency flashers....

We're going to dissassemble the ones on the bike now first, my friend says he's refurbished a lot of handlebar switches over the years on bike's he's restored, and says normally problems in them can be fixed....

I just got off the phone with him. He has the harness back on the bike with a fully-charged battery. With the headlight connected, he gets 12v at the fuse block output to the headlight. Following the wiring, there is a consistent voltage drop at every junction until it gets to the headlight, where it reads 8v. Disconnecting the headlight nets 12v at the headlight plug. Plug it back in and it drops to 8v....

Still, even with the battery fully charged the headlight is dim, and showing only 8v....

Just talked to Jeff at Z1, he had some good thoughts.

1. He said handlebar switches are very often problematic and should be looked into. He said they ground through the handlebars, and those grounds aren't often good due to the stem bearings.

2. Before that, even, he suggested disconnecting everything, horn, blinkers, tail light, etc. and see what that does to the 12v 8v drop. If it has gone away, simply reconnect things 1 at a time till it the problem reappears. Then you know where it is....

I tried the kickstarter.... instant, immediate, perfect start with no choke, no throttle. Shut it off and tried the electric start again .... no good. Kickstart, immediate....

I took it for another ride a couple of hours later. It started perfectly on the elctric starter, and ran great for 25 mles, or so, starting right up after each of the stops I made. After I got it home, though, I shut it off and tried to restart it. Same as before. Electric start ... no. Kickstart, yes....

On the electric starter, it doesn't appear to be firing at all; it just spins and spins. On the kickstarter, it starts immediately, perfectly, on the first kick....

My theory from the peanut gallery nose-bleed section ---

Battery voltage is being excessively consumed by something at some point or points between battery positive terminal and headlight socket. The headlight itself is consuming part of the weakened available voltage, and the electric starter consumes even more, all of which leaves insufficient voltage available to the coils, resulting in extra weak spark at spark plugs when using the electric starter.

Could disconnect the headlight from its socket and test starting engine with electric starter. But if engine cranks up and runs with headlight disconnected, it likely means only that the voltage being otherwise consumed by the headlight is now available to the ignition for a somewhat hotter spark. It doesn't necessarily indicate anything wrong at the headlight socket, because the excessive voltage consumption is already occurring somewhere else before reaching the headlight socket.

The excessive current drain while riding is exceeding the charging system's ability to keep the battery charged. So the battery just keeps getting weaker and weaker.

This theory is believed consistent with the advice offered by Jeff at Z1E (see quoted section above).

Good Fortune!

seanof30306 wrote:

...Now all I need to do is buy a multimeter. To do that, I need to understand the differences between the ones that sell for 3.99, the ones that sell for 399.00, and the ones in between, and which ones are important to me in buying the one that does everything I need to find these problems at the lowest price.

From among the meters listed, would get the $10.79 Craftsman Analog version from K-Mart (shown below).
Radio Shack might also carry an inexpensive analog multi-meter.

The digitals may sometimes be adversely affected by the bike's ignition system.

Besides, the digitals might not have even been around in 1973.

Anyhow, the FSM's show pictures where the analog meter is being used for checking and diagnosis. :lol:

Good Fortune!

HFT... Nice little automotive meter with Tach & dwell, capacitance as well... Reasonably priced too...

As far as meters go you can spend a lot, or a little, it really comes down to how much info you need. I would go to the Harbor Freight and get the cheap DVOM and also a in dash volt meter you can mount up near you other gauges. Total cost $10. I use 1 of these cheap DVOMs around the bikes, but I also have a Fluke 88 with many attachments. Which one is better? No doubt the Fluke, but the cheap Harbor Freight DVOM still does make many of the same measurements for $1.99 when on sale. It really is having a good circuit diagram and knowing the basics of a 12v DC system. I still fix things with my test "Bulb".

Well I'm betting that the Dyna system is defective. I have the exact same issues and have never been able to cure them. Not trying to hijack this thread but my issues are identical same headlight problems same battery discharge However we differ when it comes to blowing the regulators.
The quick version

1 new battery 4 times now!
2 new Dyna green coils
3 replaced 1 phase stator 4 times
4 replaced regulator 3 times
5 replaced stator with 3 phase stator
6 replaced regulator with brand new for 3 phase sytem 2 times
7 replaced rotor 6 times from 650 and 750
8 removed entire harness and sanded clean all the terminals
used electronic cleaner and tighten all connections
9 cleaned all grounds and added more grounds to system
10 coil mod helped somewhat
@ idle 11.9 vdc
@ 4k 12.5 vdc
unhook and power coil from seperate battery @idle 12.6 vdc
@ 4k 13.5 vdc
turn off everything power coils from seperate battery
kick start @ idle 13.2 vdc
@ 4k 15.1 vdc
The only common thing appears to be the Dyna ignition system
I know that almost everyone that has this setup has NO PROBLEMS. But it also appears there are a small handful who have charging problems no matter what they do. Since I can't beat it I'm junking the Dyna ignition and either going back to points or looking into a kawasaki ignition this has gone on far too long all I want to do is ride.

Checked the splice for the Dyna system? this is a well known electrical failure joint.

Solder and heatshrink tubing is a better connection then what came with the Dyna system.

Would assure integrity of connection where negative battery cable attaches to ground at rear of engine.

And assure battery terminal connections are clean and snug.

Could then jump the bike battery to a known good automobile battery (automobile engine NOT running), and repeat the voltage measurements, at the various points from the main fuse to ignition switch to kill switch to coil primaries, and also voltage at the headlight socket with headlight plugged in and not plugged in. And repeat effort to start the bike engine with the electric starter. All while battery is jumped. This should remove the possibility of a "bad" bike battery from the diagnosis.

Good Fortune!

spudbudy wrote:

Well I'm betting that the Dyna system is defective. I have the exact same issues and have never been able to cure them. Not trying to hijack this thread but my issues are identical same headlight problems same battery discharge However we differ when it comes to blowing the regulators.
The quick version

1 new battery 4 times now!
2 new Dyna green coils
3 replaced 1 phase stator 4 times
4 replaced regulator 3 times
5 replaced stator with 3 phase stator
6 replaced regulator with brand new for 3 phase sytem 2 times
7 replaced rotor 6 times from 650 and 750
8 removed entire harness and sanded clean all the terminals
used electronic cleaner and tighten all connections
9 cleaned all grounds and added more grounds to system
10 coil mod helped somewhat
@ idle 11.9 vdc
@ 4k 12.5 vdc
unhook and power coil from seperate battery @idle 12.6 vdc
@ 4k 13.5 vdc
turn off everything power coils from seperate battery
kick start @ idle 13.2 vdc
@ 4k 15.1 vdc
The only common thing appears to be the Dyna ignition system
I know that almost everyone that has this setup has NO PROBLEMS. But it also appears there are a small handful who have charging problems no matter what they do. Since I can't beat it I'm junking the Dyna ignition and either going back to points or looking into a kawasaki ignition this has gone on far too long all I want to do is ride.

OK, here's what I know, and here's an update.

First, whether your problem is with the ignition, or not, the ignition isn't going to cause the headlight to be dim, especially when the engine is off.

I messed with this awhile myself, then got some help from someone who agreed with me on a critical issue.

If the wiring running towards the headlight comes out of the fuseblock at 12+ volts, and drops at every connector until it is at 8 volts at the headlight, those individual voltage drops at the connectors simply cannot be caused by "the wrong bulb" as asserted by the last guy who worked on my bike.

The simple logic here is that whatever voltage you have going into a connector, you should have that same voltage on the other side of the connector. We pulled the harness off of the bike and started tracing wires, going to the headlight first. When we got to that first connector with a voltage drop, we focused on that connector until the voltage drop was resolved, then moved on down the line.

Despite the fact that the last guy who worked on it had pulled the harness off the bike and gone through it, pronouncing it "fixed", we found corroded and bad connectors all along the way. At that first connector with the voltage drop, we found quite a bit of corrosion. We cleaned it, put on some dielectric grease, reconnected it, and rechecked it. Better, but not perfect. We kept at it until the voltage coming out of the connector was the same as the voltage going into it, then moved on to the next connector, cleaning and replacing connectors and wires along the way. By the time we got to the headlight, we had 12.7 VAC from the fuseblock, and 12.7 VAC at the headlight connector. It is the same, whether the headlight is connected, or not, and the headlight burns brightly. We're now in the process of repeating the process throughout the entire harness, starting at the fuseblock, and going out towards each termination point, cleaning and replacing until the voltage at the termination point (and at every connector along the way) is the same as it is coming out of the fuseblock. Once we're through with that, we'll take on whatever other issues there are.

The fact is, the Dyna ignition pulls more power than a factory electronic ignition, but there are literally hundreds of members on here and on kz650.info successfully running that ignition. If there is a problem, it is either otherwhere in the electrical system, a defect in the ignition, or both.

Since you also have an issue with a dim headlight, as I did, you clearly have an issue, or issues, with your electrical system beyond any possible problems with the Dyna ignition. Before you junk it, I'd suggest you try resolving those other electrical issues.

The issues will split into two types. Charging (inbound), and draw (outbound). Each must be isolated and treated separately from the other.

As far as your charging issues, you numbers are even lower than mine were, and you've thrown more parts at it than I did.

I would suggest you disconnect everything on the bike that draws power; headlight, handlebar switches, etc. Everything. Then recheck your charging values. If they are still low, start at the stator. If it is not outputting 75 VAC @ 4,000 RPM, then you know you have a problem there. Stay with it until you have 75 VAC stator output. As many times as you've replaced it, I'd be suprised if you're not getting that sort of output. If that's the case, though, then you have to ask yourself not only why the stator might be bad, but what is causing the bike to eat all of stators you've put on it.

With all of the electrical components you've replaced, the question you need to be asking is what is killing them? I don't think it is the Dyna ignition.

As far as the ignition is concerned, try some simple checks. The tech guy at Dyna told me each coil should be drawing about 1.5 amps, and the ignition itself should be drawing about 1.8 amps, so your total draw for the Dyna S ignition should be just under 5 amps. If yours is drawing more, then maybe you have a problem with you ignition. Either way, your ignition is not causing your charging values to be low, and it is not causing your headlight to be dim whrn the engine is not running.

Trust me, I feel your frustration, I've been trying to resolve this for over three years.

Good luck

The Dyna tech help is often wrong. If you have two 4 ohm coils, the Dyna S is going to draw about 6 amps through the coils at idle if the battery is at 12v. I highly doubt the Dyna S module itself is using 1.8 amps. There would be no reason for it to draw that much for it's internal operation.

A higher wattage bulb will result in higher voltage drops in the wiring and connections. There is no way to get around Ohms law. Every connection has some resistance. At normal temperatures, there is no such thing as a conductor with zero resistance. If there is resistance, there is voltage drop. No way around it. The only question is how much drop. The cleaner the connections, the lower the drop.