Electrical Help Needed Hey gang-

Hey Gang- Any advice would be appreciated on this electrical gremlin.

1977 kz650, Dyna coils and electronic ignition installed in the spring of 2006. Battery is 18 months old. Fuses are all good. WG coil wiring upgrade done.

Battery does not seem to have enough cranking power to turn over the starter. Lots of juice to the lights but the electrical seems flat when I hit the starter button. I have left the trickle charger on for over 24 hours and it doesn't seem to help very much. Water levels are good in battery, no leaking. I checked the starter wire a few days ago and it seems fine.

It appears that I have a minor short in the handlebar/instrument cluster area as the brake light intermittently glows (barely) when i turn the bars slightly.

When jumped from my truck's battery to the bike;s battery the starter spins like a roulette wheel. I haven't put a meter on the battery but is there anything else I might try to look at befor replacing the battery?

it is the end of the riding season and I want to put the old girl away in fine form, not with an electrical gremlin festering.

I am pretty darned good when it comes to the mechanical items, but when it comes to electrical I have a better understanding of the mood swings of my two teenage daughters:)

Cheers-Colin Firth-Ontario Canada
1977Kz650 Custom - Latest rebirth includes 810 big-bore and lottsa go-fast goodies hidden inside.

Post edited by: reborn650, at: 2006/11/14 17:43

i wouldnt reccomend jumpstarting off a car/truck battery likely to give electrical system on bike a nervous breakdown.id take the battery someplace and have it loadtested.as far as the wiring problems in bars goodluck,they can be really easy or a real pain.

reborn650 wrote:

It appears that I have a minor short in the handlebar/instrument cluster area as the brake light intermittently glows (barely) when i turn the bars slightly.

What I know about KZ650s and their wiring harnesses wouldn't fill a shot glass, but it's a lock that the problem is associated with a that short.

Kaw headlight buckets make the best bowl of spagehtti this side of Naples - always a good place to go hunting for Lucas Connections (tm).

Another spot to go nosing around is inside the handlebar switchblocks around the turn signals/dimmer.

Might be that the WG Coil Mod wiring needs looked at - a boffo-ed crimp, a bit of unwound tape...

Somewhere in the power circuit, you're grounding to the frame.

Also a good idea to check the amperage on your fuses for the correct value - surprised that you haven't blown one along the line...

Could be worn brushes in your starter...dirty commutator?

wireman wrote:

i wouldnt reccomend jumpstarting off a car/truck battery likely to give electrical system on bike a nervous breakdown

I am pretty sure its only a prob if the car is on while doing so...if it is off it should be fine...reason saying is while on the reg/rec's in both the car and the bike are trying to do the same job but to diffent levels...the bikes R/R will fry...not to mention other stuff I am guessing

scumbag wrote:

Could be worn brushes in your starter...dirty commutator?

It's possible that there's multiple causes, but a starter ready for the nursing home won't make the headlight glow.

Wireman's got a point about jumping off the truck - I'd take a jump in a dark parking lot miles from home, but I wouldn't make a daily ceremony out of it.

oh most certinly ptero....I am not saying any everyday thing...but if done its best to leave it off

oh and bad brushes will stifle power else where when the starter in not in use?

funny story I was out lookin at this early 90s FZR600 that I was gunna try and do some mild streetfighter lookin mods and turn it around for a profit....the kid who was selling it hooked it up to his riced out civic and proceded to hook the cables up the same way he had done it before and teh time before that with the car on....I just said thanks and got in my truck....

and now back to helping Colin...

AFAIK the starter switch does not deactivate a headlamp relay on this bike.

So, you can load test yout battery by first eliminating any bad grounds. Do this by observing the headlamp whe starting ff the external battery conected to the bikes battery posts. If it doesn't dim, then all is well.

Next do the same test with your bikes battery. If the headlight dims either your terminal conections to the bike battery are dirty OR your battery is weak. If you clean the terminals and the headlamp still dims upon starting, the it's time for a new battery.

Inexpensive wet cell motorcycle batteries are made with fewer plates than one would want in a battery expected to last a log time. Why does the number of plates make a difference? When discharged the batteries chemistry deposits deposits lead sulfate on the plates. It is not all driven off when the battery is charged. The result is less plate area which reduced the maximum amperage that can be drawn from the battery.

Read about it here

-Duck

Duck is probably dead on. The battery is showing good until loaded at all. Be careful they can blow when they get an internal short.

If you know you have a short then I'd fix that before putting a new battery in the bike. No need to load the wiring any more than it already has experienced. After using the car battery I'd check around the fuse box for any signs of melting, that short just took on a heck of a lot more amps. :S

The voltage going to the starter button is teed within the switch to the same voltage that is being used as the TRIGGER on your coil relay mod (was originally the power to the coils). This voltage hits the solenoid and closes a contact. Once closed, the power to the starter is essentially a direct shot from your battery POS terminal to the starter. It is highly unlikely that the tail light problem is associated with the starting problem.

If you have little power to start the bike, you can check for sulfation on the cells by one of two methods. Take the battery out and get it load tested. A bigger bike shop may have a load tester appropriate for a bike OR buy a VERY inexpensive manometer. This is an eyedropper with some colored balls. You hook a small hose to the eyedropped and draw in battery fluid from each cell. If ALL balls float, the battery cell is GOOD, if only some float, then it is sulfated and going bad and if none float it is dead as a doornail. I test all batteries after topping off and charging. It is very likely your battery has at least one bad cell.

OK, to the tail light issue... I gotta know what type right hand switchgear you have. IF you have one where the headlight comes on automatically when the key is turned on, the problem is in your ignition switch.

First, your taillight has a dual filament bulb. The running light is the one lighting up since the brakes have to be applied to complete the circuit for the brakelight to be lighting... The wire used to power the BRAKE RUNNING LIGHT is red (blue for the brake light). If you have an ON/OFF or ON/PO/OFF switch, the tail running light is tied in with the function of this switch. This means, that since the bar movement causes the taillight to flicker, there is likely a short probably in the switchgear connector or in the connector within the headlight shell. The power to light up the brake light comes from a fuse through the ignition switch. It then connects to the right hand switchgear via a connector; generally in the headlight. There is also a connector where the power to the tail light running light is carried and this is the major connector that connects the right hand switch gear back into the main harness... If I had to guess, I would say this guy is the culprit as you won't generally move the ignition switch connector inside the headlight shell.

I would guess that a hot wire leading to or out of the switchgear to harness connector is touching the red wire coming out of or going into the connector down under your tank. This connector is generally outside the right side of the steering neck and is prone to bumping and loosening (and scraping) when the tank is removed a lot. On some later models, like my ST (KZ1000E1), the switch gear connectors go through holes in the steering neck and connect INSIDE the steering neck where they will be out of the way of rubbing from the tank.

Here's an update. Fellow kz owner secondtimearound came over to help. Thanks Barry.

Had the battery charged today at local bike shop. It cranked over and the bike fired up nicely. Timing was dead on.

Bike was running on all 4, then it lost #3.
Tried the electric starter again and battery seemed pooched. Fired up with the kickstarter, but #3 pipe was cold.

Pulled the cap on #3 and the plug wire connect at the coil seemed to be corroded. Thought I had cleaned it well enough but did it again.

Bike fired up when I jumped it from my non-running truck.

Cheecked the terminals on the battery and the positive side was loose. Tightened it up as best I could but the lead terminal seemed to be cracked. Tried again and fired it up again. Started on all 4 but then lost #3 again. Started backfiring through exhaust.

My MacGyver/electrician/mechanic friend came over and said if the battery was pooched, only putting out 9 or 19 volts, it would probably cause one of the cylinders to start failing.

I'm gonna bite the bullet tomorrow and pick up a new, top of the line battery.

I'll keep you posted.

Thanks-Colin Firth-Ontario Canada

Hi Colin,

You should be able to get a new battery for about $40 CAD - don't worry about brand, they all come from the same factory anyways (Exide/General Battery/Yuasa). If you were on this side of the country I could set you up with an Interstate...

When you put it in I think you'll find your starting problems will disappear and your spark will be stronger than ever before. It's because your electrical system can now get all the power from the dynamo instead of having it stolen by the battery.

Battery life varies with how long you leave them discharged - a few days fully discharged will wreck a battery, so just because it's "only" 18 months old means nothing. Get it tested with a proper battery tester or just get a new one and keep it well charged.


As for your rear lights, check the connectors in the headlight bucket, there's always one or two in there that have bad contacts.