Headlight causing electrical problems?

'79 KZ650 B3

OK, so I've been having massive electrical problems with that @#$%^&!!!! KZ650 since I bought it nearly three years ago. I've replaced the battery twice, the regulator/rectifier four times, the stator twice, then had the stator rewound, gone through every inch of the harness multiple times, etc., all to no avail. It's never gone 400 miles without having to be towed back in. The guys at AAA recognize my number when I call.

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.

I just got an email from my friend who's working on the bike. He's a retired railroad electrical engineer who restores old motorcycles. He knows his stuff. Here is what he said:

"Your headlight is an automotive sealed beam not a motorcycle. That is why I was only reading 8V, when unplugged 12V. Car HL have way too much internal resistance and will suck the charge out of a battery faster than the alternator can replace it in a motorcycle.
At this point I can not guarentee anything exept that it is a potential killer. I am digging up a beam and will change it out today."


When I first went to test ride the bike before buying it, the battery was dead. Not knowing any better, I didn't object when the guy jumped it from a running truck (I now do know better). As I rode the bike that night after buying, it systematically blew out every bulb on the bike. A check the next day showed it was charging at something like 24v, so I went to a local motorcycle shop/indoor salvage yard and bought a regulator/rectifier (used), and all new light bulbs, including a new headlight. Since then, it kills the battery in less than 400 miles of riding every time, and we've never been able to solve it.

Could it really be that simple?

The KZ650 takes a regular automotive 7" sealed beam headlight; 50 watts high beam / 35 watts low beam. These originals were not halogen, but believe me when I tell you you can run a new halogen sealed beam or H4 type bulb with no problem if the electrical system is functioning properly. Stick with 65 watts max. I ran 100 watt bulb for years, but that may have been pushing it a bit.

The factory service manual describes how to diagnose electrical problems. I would use it and start at the dynamo (alternator). Ed

I have been running automotive 7" halogen sealed beam headlights on my KZ 750 for about 28 years. No problems.

Would check charging system by measuring voltage across battery terminals at idle rpm (look for 12~13 Vdc) and at 3000~4000rpm (look for 14~15 Vdc).

May need new reg-rec.

Click here > Reg-Rec from Z1E

Good Fortune!

seanof30306 wrote:

'79 KZ650 B3

1)"Your headlight is an automotive sealed beam not a motorcycle... Car HL have way too much internal resistance and will suck the charge out of a battery ..."

He has Ohm's Law backwards; Should have said too LITTLE internal resistance. :huh:


seanof30306 wrote:

'79 KZ650 B3

2) "As I rode the bike that night after buying, it systematically blew out every bulb on the bike. A check the next day showed it was charging at something like 24v, so I went to a local motorcycle shop/indoor salvage yard and bought a regulator/rectifier (used)..."

Good news is...:
Congrats, you did the right thing here.

seanof30306 wrote:

'79 KZ650 B3

3) "Since then, it kills the battery in less than 400 miles of riding every time...

Bad news is...:
Sorry, you may have bought someone else's faulty Reg/Rect unit (been there, done that, you're in good company). :pinch:


As suggested already by others, you need a new working Reg/Rec unit so you can get riding now.

Be prepared to check, clean, repair and or replace the following:
- Any and all Connector's/Contacts between Battery and Headlight.
- The Ignition switch.
- The Headlight ON/OFF switch, if equipped.
- The HI/LO switch.
- The +12 Vdc wiring to the Headlight.
- The Battery Ground (Black/Yellow Marker) wire to the Headlight.
- The Battery Ground to the Engine (bolt at rear-right side of transmission.

IMHO, you need a Service Manual for your bike ASAP... whether or not you or a buddy are doing the maintenance. When set up and maintained to spec, these bikes are reliable and bullet-proof.

Best of success,
Bill

PS
Please add your year, model and location to your signature to get the best and most accurate responses... and yes it is considered very friendly!
Bill

It depends on the wattage of the bulb itself that would effect the load current draws...

Henceforth, if you have the wrong wattage bulb thus current drain, installed then yes you could effectively drain the battery... but only to a point....

Meaning, in a perfectly working electrical system, the charging system and battery will only produce so much energy (Voltage). If a larger wattage bulb is installed, it would just be dimmer in operations, not drain your battery...

Plain & simple, Ohms law applies, nothing more or less...

Voltage(E) = Resistance(R) X Current, Amperage(I)

Power (Wattage) = Voltage(E) X Amperage(I)
Power = I(squared) X Resistance
Power = E(squared) / Resistance

My best guess, you have a weak or missing ground somewhere... Translation, you have energy leaving the battery but not returning in the charging cycle.

Or, your charging system/rectification/Regulation is not to spec....

OMR

Guys,

Thanks for the responses. A couple of things:

I didn't post the entire journey with the electrical on the bike, as I didn't feel it was relevant to the question I was posing about the headlight.

After the first replacement with the used regulator/rectifier, and the bike still kept dying, I put another used regulator/rectifier, died again, a brand new one died again, another brand new one. It kept blowing all the resisters out on one side.

Replaced the batter with a new one, replaced it again with another new one after that one was killed.

During that process, I also replaced the stator with a used one, the bike died again, then had the original stator rewound by Ricks.

Have also replaced the part of the harness at the stator and the connectors for that and the regulator/rectifier.

Have the Clymer manual, the factory service manual, a downloaded electrical troubleshooting guide from a member here, and a factory wiring diagram blown up to 11 x 17.

Have been over every inch of the harness more times than I can count, have cleaned all grounds and connectors more times than I can count.

The Clymer manual, the factory service manual, and the guys at Ricks outlined multimeter tests for the regulator. It is good.

The Clymer manual, the factory service manual, and the guys at Ricks outlined multimeter tests for the stator. It is good.

The Clymer manual, and the factory service manual outlined multimeter tess for the battery. It is good.

The Clymer manual, the factory service manual and the guys at Ricks outlined output ranges for the charging system at idle and at 3,000 rpm. It is good.

Whatever the problem is that is causing the bike to run the battery down after less than 400 miles again and again and again despite my having tried and tried and tried to figure it out, I am confident that the problem is not the regulator/rectifier, the stator, or the battery.

At different times, I've added additional grounds, grounded the coils, etc. as I've tried the varying and often contradictory advice I've gotten as this awful, terrible nightmare has gone on and on and on for two years and 10 months of unbelievable grief and drama. Before anyone gets excited, all additional grounds and the coil grounds are gone now.

The point I'm making is for nearly three years, I have been starting back at step one and following every step in the book(s) over and over and over, with no success. This has been the absolutely most frustrating experience of my life (and I was married!). All kidding aside, I honest to God have come within an inch of setting that @#$%^&!!! KZ650 on fire twice. I mean literally standing over it with a gallon of gas and a lighter while my friend pleaded with me not to do it. If anyone is interested in the awful, terrible, soul-destroying details of this nightmare, just take a look at all the threads I've started here on it since this terrible ordeal began.

The only thing I could think of that could keep causing this was an intermittent dead short. Last fall, before it died again, I was out riding it with the usual slowly dimming lights, trying to get it home before the inevitable call to AAA. I reached out to adjust the headlight. As soon as I touched it, the lights went way dimmer, and it started running noticably worse.

The running worse puzzled me, as the bike has the WG coil mod, so the engine should be powered directly from the battery, shouldn't it?

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 one place I'd never been in the harness was inside the handlebars, so this winter, we took the entire harness off the bike and went through the whole thing, using bits from it and the other two I'd gotten to (hopefully) come up with one harness with no problems. We are in the final stages of that process and have yet to see if that resolves the problem.

The question I posed about the headlight was really meant as a simple by the by ..... I really don't what other steps could possibly have been taken during this process to find the solution.

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.

Looking back at this post, I see where my incredible frustration has boiled over a few times. Please understand that none of this is directed at any of you guys who are trying to help. I only went there so people wouldn't think this is simple a "get the service manual and follow the troubleshooting guide" issue. That's been done again and again and again.

No eBay APP ID and/or Cert ID defined in Kunena configurationseanof30306 wrote:

...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....

Happened to see this one:



Good Fortune!

Thanks dude, I'll watch that one. 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.

Also, tucked back in the headlight bucket were two blue wires with bare, stripped ends that would arc when they touched ground. Studying the wiring diagram, it appears they originally ran to the factory turn signals and have constant, switched power. I guess they were for running lights?

Anyway, logically, that would at least seem to explain the sudden drain when I djusted the headlight, if not more of the problems.

BTW, in searching this on here, I came across a post from a member who had been inspired by the WG coil mod and had done something very similar for his headlight. Is that a good idea?

seanof30306 wrote:

...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.

Maybe the headlight connector is internally shorting when the headlight is plugged into it??

Good Fortune!

seanof30306 wrote:

- 1)... With the headlight connected, he gets 12 v 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 8 v.

This is one of your many problems. Change those bullet or multi-circuit connector contacts now... that's exactly what I did. New OEM types are available from Z1 Ent for pennies. You can even get the white plastic shells or individual clear plastic bullet type connector covers for cheap and that neat little contact extractor tool... again, I did. You should and will get 12 Vdc at the Head Light.

seanof30306 wrote:

-2) ... Disconnecting the headlight nets 12 v at the headlight plug. Plug it back in and it drops to 8 v..."

These are normal readings:
- The first is the no-load or virtual voltage.
- The second is the loaded or actual voltage.

Our job to help you get the second voltage to be within 0.5 Vdc of the first voltage.

I had contact problems in all my handlebar switch gear too. As you have guessed/witnessed, they won't solve themselves. Watch for flying ball bearing from there.

seanof30306 wrote:

- 3) Also, tucked back in the headlight bucket were two blue wires with bare, stripped ends that would arc when they touched ground.

Just to state the obvious here (no offense intended), cap these wires (heat shrink tubing is great and tie them back in to the harness to avoid future problems.

seanof30306 wrote:

BTW, in searching this on here, I came across a post from a member who had been inspired by the WG coil mod and had done something very similar for his headlight. Is that a good idea?

Ummmmm, this member thinks so. :whistle:
Link

Best of success,
Bill

The BLUE wires are the running light circuits for the front turn signal/running lights as suspected.I have an 82 GPz1100 B2 with similar wiring.