Hoping someone can help me with an issue with my charging system i've been trying to solve for 3 years.
I purchased a 1976 Kz900A4 3 years ago. I am the 3rd owner of the bike. I was noticing when i came to a stop that when my i have my headlight, brake light and turn signal on the lights dimmed and turn signals struggling to stay on but when i increased the RPM's they would turn bright. At idle with all lights off the voltage was 12.2 to 12.5 which is very low. With all lights on i barley broke 12volts at idle but it would increase as i raised the RPM's. The battery wasn't the issue because i have an identical bike that idols at about 13.4 volts and swapped the batteries and it still showed about 12.2. I went ahead and replaced the Regulator and Rectifer with the new combo units from Z1 enterprises and still no luck. Then i replaced the stock stator with a new aftermarket one from Z1 with again no luck at all. I tested the new stator on AC current and it showed about 50 volts. This is where i left off.
Some one told me i might have a short somewhere and that i would have to start disconnecting all non-vital components like headlights, turn signals horn, etc to try and pinpoint the short. Does this sound right?
The previous owner removed the stock handle bars and replace them with cafe bars which are shorter in lenght. The wiring harness was scrunched down because of the lenght. Can this be the issue where a short might be? What else can possibly be the issue here? Thanks for your help.
A bad splice will add resistance to any circuit. If possible see how the wires were reduced in length.
Try this when cleaning the electrical connectors:
Cleaning Motorcycle Electrics
Get some of the De-Oxit electrical contact cleaner and figure on spending a good day going from the front of the bike to the back. It’s a plastic safe cleaner/preservative.
is their website.The Radio Shack Stores along with other electronic supply places sell it.
On the older Kawasaki's, a majority of electrical connectors are inside the headlight housing requiring removal of the headlight, then the fun begins.
Do one set of electrical connectors at a time to avoid mixing up what connects to where. Usually disconnecting, spraying with De-Oxit and reconnecting is about all you'll need.
However, when encountering the green crud of corrosion, a brass wire brush may be needed on the pins you can reach.
Some 400-600 grit wet and dry sandpaper strips rolled into a tube should reach the male and female pins in the more difficult to clean connectors.
Smoker’s pipe cleaners, cotton swabs and wooden toothpicks work as cleaning aids.
Really small electrical connectors may require the use of a welders tip cleaning tool assortment.
Most pins in the connectors are coated with a thin plating of tin, and others may be nothing more than copper or brass.
If moisture is added, the resulting corrosion lowers the voltage/current being carried causing dim lights, slow engine cranking, slow turn signal responce and lower input voltage to the ignition coils resulting in weak spark.
The left and right handlebar switch pods will need attention too as they have circuit functions like turn, horn, run/stop, and start.
Usually a spritz or two with actuation of the switch is about all needed for these switches unless corrosion is detected and then careful disassembly is required.
The ignition switch may or may be not sealed to allow spraying the internal contacts. I urge caution if attempting to open this up as springs, and ball bearings may fly out never to be seen again!
If your bike has the older style glass tubed fuses, I suggest replacing them as vibration can cause internal failure. AGX is the type used, and most auto parts stores can get them for you.
Clean the fuse holder clips, looking for signs of overheating(discolored insulation, signs of melting).I use metal polish on a cotton swab, followed by spraying another clean swab with the De-Oxit and then rubbing the inside of the fuse clip.
Each "Bullet Connector" will have to be sprayed to ensure good connectivity, especially the ones going to the energizing coil of the starter solenoid.
The alternator output “Bullet Connectors” are usually behind the engine sprocket cover and will need inspecting and cleaning too.
The turn signal light sockets will benefit from a spritz from the contact cleaner along with the tail light/brake light socket.
Some brake light switches can be sprayed on the actuating rod, with the spray running down inside to the electrical contacts, others may be sealed requiring replacement if the switch is intermittent in operation.
Some people put the Di-Electric Grease on cleaned terminations/connectors, I don’t, as I’ve read/heard it can cause problems when it gets hot, actually insulating the connections, so the choice is yours to use or not.
I think I've covered about all of the electrical systems on the bike.........
The Dreaded Shorting/Intermittent Electrical Problem!
Here is the most basic method I know(Taken from
by member Patton)
1. Charge your battery and have it load tested if you can. The floating ball hydrometer can be used to check the specific gravity of the charged cells in the battery.
2. Disconnect the Black lead from the (-) Battery terminal... or Red from the (+) Battery terminal, it does not matter which one. Just 1, not both!
3. Connect one of the following test setups in series with the Battery terminal and lead:
3.1 A 12 V light bulb,
3.2 A 12 V test light,
3.3 A 12 V test buzzer or,
3.4 A 12 V horn... you get the idea.
4. With the Ignition Switch OFF, go through your harness and wiggle the wires while looking/listening for the test setup to go on/start buzzing.
5.With the Ignition Switch ON, repeat the test except this time the looking/listening for the test setup to go off/stop buzzing.
6. Be prepared to open the Ignition switch and check/test for solder joint failure and or circuit board micro breaks (don't ask how I know this ).
7. Be prepared to pull the wires out of the Head Light to test for failures at or near the grommet.
8. Be prepared to open the harness at or near the Steering Neck for failures. This is where wires tend to exhibit fatigue due to repetitive movement.
9. Be prepared to open the left and right switch gear to search for rust and or broken parts. CAUTION: watch out for flying springs, ball bearings and stuff. Do indoors on White sheet (again don't ask ).
10. Be prepared to follow the heavy gauge wire from the Starter Solenoid (Relay) to the starter for bare wire exposure. Especially near bends and grommets.
11. If you can reproduce the fault symptom your are pretty much home free. Be prepare to find and repair/replace any internal wire breaks, insulation break downs, exposed wires, rubber grommet failures, etc. Often, shrink tubing will solve the problem temporarily until something better can be done.
Also when the previous owner did the handlebar swap, he may have had the wiring hit a sharp edge on the bars or clamps, creating electrical problems.
If you need information about heatshrinkable butt connectors(electrical splices), I have a good listing of where to get some, along with harness tape of the non sticky type used by the vehicle manufacturers.
At Old Man Rock,
All tests performed were in the ideal range. I am steering towards a bad splice or grounding in the wiring harness. Next I will start breaking down the entire wiring harness looking for a bad connection. I also noticed that on the positive lead coming off my battery to the starter solenoid there is copper showing. Could this be an issue as well?
Kaw900 wrote: ...issue with my charging system...1976 Kz900A4...At idle with all lights off the voltage was 12.2 to 12.5...would increase as i raised the RPM's. The battery wasn't the issue...replaced the Regulator and Rectifer with the new combo units from Z1 enterprises and still no luck...replaced the stock stator with a new aftermarket one from Z1 with again no luck...tested the new stator on AC current and it showed about 50 volts...Some one told me i might have a short somewhere and that i would have to start disconnecting all non-vital components like headlights, turn signals horn, etc to try and pinpoint the short. Does this sound right?...
Regardless of some excessive current draw for whatever reason from wherever, am thinking the charge at 3000~4000 rpm should be 14+ volts (given a good battery, properly serviced, that holds a charge, and with good cable attachments at terminals and ground lug to rear of engine).
Pre-battery electrical is all charging system (generator, rectifier and regulator, together with the wiring associated with those particular components). Their purpose in life is keeping the battery charged.
Everything else is post-battery, such as ignition and chassis electrics, which rely totally on the charged battery, and don't care how the battery manages to stay charged.
All tests performed were in the ideal range --- not without 14~15 volts measured across battery terminals at 3000~4000 rpm.
...am steering towards a bad splice or grounding in the wiring harness. Next I will start breaking down the entire wiring harness looking for a bad connection. --- Success here would imo be limited to wiring associated with the charging system components, but not with the ignition components or chassis electrical components, or wiring not associated with the charging system components.
What is voltage measured across battery terminals at 4000 rpm?
"At idle with all lights off the voltage was 12.2 to 12.5 which is very low. ".... Is this battery voltage measurement at the ignition switch>coil output?
Good battery(-) to frame > engine case ground?
Ok, here's what I'd do (as accomplished in my 76 KZ900 electrical restoration).
Note: Due to rectifier diode bank open, I recently changed to Z1 combo unit obtaining 13.7Vdc (3500RPM +) without accessories turned on. ~13.2Vdc with lights on!
Disconnect all outside running electrical components such as lights, break/running lights, relays etc... Basically get the electrical to bare minimum requirements. In using switches versus OEM bar switches, all good where ideal 4krpm @ 13.5Vdc measurements are to spec?
Now add ignition switch back in, back down to 12.5Vdc?
If so, Z1, has brand new ignition switch for $20....
You could also d-connect starter all together and go with kick start... Verify voltage measurements with Dynamo, rect/reg, battery to coil/ignition Dyn-S.
Very well explained...making me think about that possitive battery cable with exposing copper. It could have oxidation not allowing a strong current back to the battery. Gonna purchase a new one and replace it.
Because of the new combo rec/reg and new stator, am more suspicious of the wiring and connections between these components, and would assure integrity of ground wire from the combo unit.
As MFolks suggested earlier, one of the connectors in the wiring may be crusty, for example where the combo ground wire connects into a chassis ground wire. Which might be causing a problem, because the combo unit does require a good ground in order to properly function.
I've successfully run a combo unit (the plug-in version) from Z1E for many years.
Yesterday I went through all the tests again on the Stator and it all checked out. Then i went through the wiring harness disconneting non-vitals looking for a spike in voltage with no luck. Finally i decided to peel back the installation on the possitive battery terminal which should have been the first thing i did and to my surprise the copper was un-wound and alot of splits in the wire. This could very well be why when i raised the RPM's i would get a spike in voltage because it was trying to push as much current through such little contact. I already ordered a new cable and should have it installed by friday. I will let you know the result by then. See the picture.
I replaced the possitive battery terminal today and still no luck. Still idling at 12.1 volts. I again took the regulator rectifier combo unit out of the good bike and installed it in this bike with again no luck. So i've out ruled the battery, stator, regulator rectifier, went through the wiring harness. Would the coils be an issue with the charging system?
Kaw900 wrote: ...Still idling at 12.1 volts. I again took the regulator rectifier combo unit out of the good bike and installed it in this bike with again no luck. So I've out ruled the battery, stator, regulator rectifier, went through the wiring harness. Would the coils be an issue with the charging system?
If not already done, would remove battery, assure fluid levels are correct, charge it overnight, then have it load-tested, even if it's a brand new battery.
Imo, it's unlikely that the coils are an issue with the charging system.
The FSM covers individual tests for the alternator (dynamo) output, and rectifier and regulator functions.
As known, charging starts with the alternator (aka dynamo), which needs good wiring in the stator (no short or break), and a rotor with sufficient magnetism.
Even with a perfect stator, a low alternator output may result from a loss in rotor magnetism, which may be caused by dropping the rotor or hitting the rotor, or just old age of the rotor.
I don't know how to specifically test or measure for sufficient magnetism in the rotor.