82 KZ550 Wont Start (No power to coils)

Ok guys been through pretty much the entire harness unwrapping, checking wires, cleaning contacts and connections and re wrapping contacts. I couldn't find anything out of the ordinary. Any more suggestions?

check the kill switch again and us a analog meter so that you can check the needle swing make sure that the needle moves when you are checking the resistance in the switch also check thepower coming in and out of the ignition fuse make sure your getting 12 volts at least.

Let's see here.....

In reviewing the attached schematic you should be able to measure (Volt meter) the following....

The yellow conductor coming off your ignition switch is the +12Vdc (battery (-) ground reference)to the starter & engine kill switch. In the default switch position, you should have +12Vdc at your coils!

NOTE: For now, measure directly from the Vdc and ground locations depicted, not the frame for this may be where your problem lies, poor frame grounding!

NOTE: Maybe I missed it but does the starter motor turn when pressing the starter button? Reasoning, this will inform you if the +12Vdc is present at these two switches (starter and kill)...

@ the Kill switch yellow conductor:
Measure the +12Vdc from the battery (-) negative to the Vdc depicted... +12Vdc Yes/No???

If good, measure the +12Vdc from the the frame/chassis negative to the Vdc depicted... +12Vdc Yes/No???

If all checks above depict +12Vdc to the yellow conductor feed into the engine stop switch then measure the red/yellow conductor (switch output) feed to the coils, should measure +12Vdc as well! If not, then this is where your problem lies! The kill switch is fuckied!

If you do measure +12Vdc at the red/yellow conductor off the kill switch, then measure the red/yellow feeds into both coils, you should read +12Vdc...
If not then this is where your problem lies...

If all good so far, measure the red/yellow and black/yellow feeds into the IC igniter... you should read +12Vdc...

Have you tried dis-connecting & then re-connecting the igniter plug? Do the same with the pick up coil connectors...

Let us know what you measure & we'll go from there...

OMR

mushroom_toy wrote:

...only receiving about 1.5volts at the postitive on the coils....

Sorry if already covered, but:

What is voltage across battery terminals?

What is voltage measured between
positive battery terminal and bike frame?

Thinking maybe a poor ground connection where
negative battery cable attaches to frame (or engine).

Good Luck!

you betcha the k.i.s.s therory in action once again.

GPz550D1 wrote:

loudhvx wrote:

Lou,

I have a '81 gpz550 like yours and noticed your setup to hold down the timing advancer, which is interesting. I had mine off today to lube it and the stock 8 x 63mm bolt had been replaced with an aftermarket bolt. Just curious if the stock bolt is prone to failure? Maybe people break it by trying to take it off the wrong way? Just curious. Thanks.

Robert

Actually, that advancer is not mounted to the bike. I just threw in any old common bolt to hold the thing together for storage. But you are correct... I've seen several advancers mangled there, mostly I think it's because people use the small bolt to turn the motor, when, in fact one should turn the larger hex head to turn the motor. The larger hex head is not a bolt, it is just keyed to the advancer hub which is keyed to the crank.

Edit: Oops, Timebomb33 already said this.

Another thing, you mentioned the blue/white and yellow black are both grounds. this is true of the yellow/black usually. Blue white is usually a power lead. However, with contact ignition the blue white will test continuous to ground.

I spent an extra hour debugging a loose battery connection because I thought my bike was hosed. I was checking continuity between the hot (yellow/red on mine) lead to the coils and found that one coil was grounding out (or so it seemed). Turned the bike over by hand and found that the other side was now shorting and the original coil was not.

Also, because of the light bulbs I found that my blue/white and red/blue (keyed hot wires) were grounding as well. Stupid multimeter can't tell the difference between a short and a light bulb and stupid owner (me) can't tell when multimeter is doing this.

Anyways, as others have said, just run a lead to the coils power supply from the battery and try it then. Don't start it though as you won't have a way to kill it without stalling the engine.

Questions though:
1) Have you checked the battery terminals (would have saved me 2 hours)?

2) Have you adjusted the timing and points gap?

3) What voltage is your battery reading?

4) Which coils feed which cylinders, also, which coils get which black or green wire from the points?

The last one is because I helped a guy work on an engine and for a week he couldn't get it to spark at the right time. Turned out his crank position sensor was 180 degrees out of synch. Worst case with yours, switch the black and green wires and see what happens.

Alright finally got her running. Still cant believe what it was. I finally went ahead and took the stop swicth/starter button and wiring harness off tyhe bike for further examination. Checked all the wires and contacts and they were good except the red/yellow going into the harness. it had 12v into one side and not out the other. So i unwrapped the harness and checked the wire....to my surprise nothing was wrong with it. Then i tugged on it a bit and sure enough it broke in one spot. Somehow the wire got burnt, cut or just degraded without the insulation being hurt at all, so the wire looked completely in tact. Very very weird. Im kinda pissed it took me two months to find out it was one measly part of a wire, but at the same time very happy since shes runs so good. I pretty much got a Running bike with new tires, brakes, etc for $240.

Everyone thanks for all your help, Im sure I wouldnt have checked it over again if it were not for yall.

A self powered continuity light or a home made buzzer circuit along with a good multi meter can reduce the amount of cursing and tool throwing when working on electrical "Gremlins".