'82 GPZ 550 woes - problem testing alternator and

Hi,

I've a '82 GPZ 550 that's got a few problems that I'm trying to sort out. They're sort of related. I guess I'll start with the main problem. I know it's a lot of questions (long post), and I thank you for taking your time to read this.

#1 My 82 GPZ 550 had a problem with one of the cylinder not working (do you call it "cylinder not firing"?), plus unable to keep running unless throttle's applied (so stalls if idling, etc). At first it was the third cylinder from the left; I found out by touching the pipe. Got the carbs cleaned, the stalling without throttle problem seems to went away, and the third cylinder works now too.

But, now the fourth cylinder's pipe is cold. I've drained that carb, and gas did come out, so it's not float getting stuck.

#2 Now comes the second problem. Someone looked at my bike a while ago, and he told me that the reason why one cylinder isn't working might be because I don't have enough amperage, which makes it unable to cause enough spark, hence the cylinder not working. When I showed him, it was 10 amps, and it's supposed to be 12. He suggested me to get a new alternator, and someone (including someone from this forum) told me to test the rectifier and the alternator first.

My friend disagreed staunchly when I told him, but I wanted to test both anyways. I also want to ask you guys, could it indeed be an alternator or rectifier problem?

Anyhow, I was just about to test the alternator first, following my Hayes service manual, and realized that I couldn't find the "three yellow alternator output leads" that I'm supposed to disconnect after warming up the engine. I see yellow wires on my bike, but they're all bundled with wires of other color as well, which is confusing me.

I've taken a couple photos so that it might help you guys help me find the right wire (pardon my stupid newbie move, of not being able to find the wire)

i34.photobucket.com/albums/d110/will_dou/IMAGE_107.jpg

This one's on the left side of the bike. There's a wire sticking out the engine cover, which is half cut off in the picture, on the very left side. I don't know where that leads to actually.

i34.photobucket.com/albums/d110/will_dou/IMAGE_108.jpg

Here's a picture of the perspective zoomed out, so you can see where that is.

IMAGE_113.jpg

This is the right side of the bike, another wire coming out of the cover. It goes to the igniter(sp) in the next picture (the more silvery one)

IMAGE_110.jpg

Is the black one the rectifier?

#3 I read in an older post where someone tested to see if the spark plugs were making sparks (I think). How do I test this, if I need to?

Thanks!

Your cylinders fire in pairs. 1 and 4 at the same time, and 2 and 3 at the same time. If 1 fires, then 4 is likely firing too. Same goes for 2 and 3. The only way one cylinder won't spark is if you have a shorted plug wire, or bad plug, or the coil is faulty.

If 1 or 4 don't fire, swap the spark plug wires for 1 and 4. If the problem moves to the other cylinder, then the coil, or wire is bad. If the problem stays on the original cylinder, then the plug is bad or the carb/mixture is wrong on that cylinder.

Same goes for 2 and 3.

To test for spark outside the engine, take out all the plugs so that cranking the engine will be easier without the compression. Keep each plug wire connected to it's plug and make sure the metal part of the plug is laying on the engine. Crank the engine over. There should be sparks on each plug once per crank revolution.

If the battery is strong enough to start the bike, it is strong enough to run the engine. If you are losing voltage to the coils (you don't say how you "showed 10 amps") then there is a wiring issue or dirty connections/switches/fuses. Your whole ignition will use about 3 to 4 amps in total, by the way. (13v / 2.5amps)*(2 coils * .33 duty cycle) = about 3.5 amps.

Wow, that is a really in-depth diagnosis. I'll test it tomorrow as it is raining out.

On testing for sparks outside the engine, and keeping the metal part of the plug laying on the engine, did you mean just to unscrew it and not take it out? I'm not quite sure what you mean by laying it on the engine.

About the battery, I must apologize for mixing it up. It was 10 volts actually (another newbie move). I have a button on my bike that I can press and it'll show the voltage (my friend said he doesn't have it on his bike or it's different somehow). Hope that'll clarify some things.

How will I be able to tell why it's only 10 volts? And if battery's not the problem, what can contribute to it?

Many thanks for the detailed explanation, it's a lot of help.

ps. Just realized that two of the pics are messed up, fixed.

reinhart_menken wrote:

On testing for sparks outside the engine, and keeping the metal part of the plug laying on the engine, did you mean just to unscrew it and not take it out? I'm not quite sure what you mean by laying it on the engine..

Yes, sorry, I meant take the plugs out of the engine, and then reconnect each plug to it's plug wire, then lay them on the engine so the silver metal part of the plug is touching the engine.

reinhart_menken wrote:

About the battery, I must apologize for mixing it up. It was 10 volts actually (another newbie move). I have a button on my bike that I can press and it'll show the voltage (my friend said he doesn't have it on his bike or it's different somehow). Hope that'll clarify some things.

How will I be able to tell why it's only 10 volts? And if battery's not the problem, what can contribute to it?

Many thanks for the detailed explanation, it's a lot of help.

ps. Just realized that two of the pics are messed up, fixed.

If the battery really is 10 volts, it will most likely not be able to start the bike. Verify with a handheld voltmeter what the voltage really is.

Thanks for the clarification, no worries.

Where and how would I test the voltage at? By that, I mean, do I test it on the battery itself, or? I've never done anything relating to electrical stuff before, so I have no idea how to do it (including where the positive and negative probes on the multimeter should go).

Just got done testing the spark plug wire and the plug itself when it started raining again (I've not a garage).

I didn't have a spark plug socket, and the nearest Autozone was a couple miles away. So, I sat on the bus for an hour and half, got the socket, and then just as I stepped out of the deli with my lunch, after I returned, it started thundering and then proceeded to rain. It stopped for a while after a little bit, so I went out and tried to get some work done on the bike.

I tested the plug wire first, and while I didn't get to see the spark dancing away from the screwdriver (using philipd's method), I definitely felt the electricity current as I moved my hand to adjust it (because I didn't see a spark). I didn't touch the metal part, but I guess I got too close - about half an inch I guess (my hand moved forward toward the narrower plastic part of the screwdriver). Managed not letting go of the screwdriver though.

Next I tested the #4 spark plug, putting it in the wire and then laid it against the metal part of the engine. First off, the #4 wire was too short (making the plug way too close to the hole for my comfort, especially after the tale of 8 feet fire), so I switched the #1 wire to the 4th position. The #4 plug gave me white sparks. I switched the #1 plug over to the #4 position again, and still white sparks.

Just as I got done doing that it started raining again, hard, so I had to put everything back in a hurry and put the cover on.

Someone told me someone told me the spark is supposed to be blue or something?

reinhart_menken wrote:

Thanks for the clarification, no worries.

Where and how would I test the voltage at? By that, I mean, do I test it on the battery itself, or? I've never done anything relating to electrical stuff before, so I have no idea how to do it (including where the positive and negative probes on the multimeter should go).

Using a multimeter, connect one end to positive and one to negative and that will give the voltage difference between the two points. If you accidentally get it backwards it will say you have -12 volts. Nothing wrong with doing that.

KawiConvert wrote:

Using a multimeter, connect one end to positive and one to negative and that will give the voltage difference between the two points. If you accidentally get it backwards it will say you have -12 volts. Nothing wrong with doing that.

Oh, great, thanks. That's good to know. I was worried if I get it backwards I'd get electrocuted or something.

Put the voltmeter's black wire on the battery's negative post, and the meter's red wire on the coil terminal with the yellow/red wire.While idling, that should be 12 to 13v. If you rev the bike a little, it should getto 13 or 14v.

Got to testing a couple things today.

So I first got around to testing what my friend suggested, switching the #4 plug with the #1 plug. It was the same story with the #4 pipe. This time though, I did notice a difference (which I didn't check before because I didn't know to look) - the #4 pipe is warm on top, but cold in the middle (where as both #2 and #3 are burning hot all through). I remembered that the only reason I knew to check the top of the pipe was because last time the #1 pipe was warm on top, so I switched the plugs again and checked the #4 pipe again (had to wait an hour or two because the weather was temperamental). It's still the same story, both #1 and #4 are warm on top and cold in the middle. I was fuming mad that I didn't find this out before (but then again, I didn't know to check), just cussing all the way though putting things back again. At least I learned all these things.

I also tried a voltage/current loss check someone suggested. I had the fuel tank off, ignition and run/kill switches both switch to on, and then checked the primary side of the ignition coil with the multimeter. The engine wasn't started for this. The reading at the ignition coil gave me 9.93V on DC. I had also checked my battery last night, with it off the bike. It gave me 12.23V, and when I tested it this noon with it attached to the bike, it gave me 12.03V. I didn't fully charge it though, because I don't have a well-ventilated space, and my place is pretty small and closed off. Plus I figured 12.23V was close Let me know if I should definitely charge it to full. I'll have to go back and change to an automatic because mine's manual (so it doesn't shut itself off when done, and I can't keep an eye on it all the time).


So...voltage loss because of the 9.93V? Someone suggested an ignition relay bypass? Is there an alternative, and shouldn't there be a fix closer to factory standard? I mean, the bike couldn't have came out the factory with that defect, so how did they compensate for that in the first place? Or are the components too old and archaic to chase down?

Didn't get to a compression test, because evidently the sockets don't fit into my bike I guess I'll have to hunt down a socket for my bike, and I can't return it. One of them was so close though. It's a 12mm I think, but somehow I couldn't get the thread to bite (or is it called catch).

Incidentally, I took a picture of one of my spark plugs. It's rather representative of the state of my other plugs.

i34.photobucket.com/albums/d110/will_dou/IMAGE_115.jpg

As you can see, the electrode part in the middle is brownish, as is the #1 plug. The #2 and #3 plugs though, are closer to white.

And here's my ignition coil, in the bottom left, and the wires with the white head goes onto the coil. I stuck the probes inside the white parts. Just making sure I got it right (well, I got the reading).

i34.photobucket.com/albums/d110/will_dou/IMAGE_117.jpg

I can't see the photos while here at work, but it sounds to me like you have a voltage loss (reduction, actually) issue.

When the bike is not running, the coils don't get current, so the voltage loss has to be upstream. Most likely in the fuse box. First thing to do is take out the fuses and really clean the fuse holders. Also look for any discoloration in the wires there. That is evidence of a bad connection on the fuse holders.

There are many other points to check, but that is the most likely. Check the voltage again, the same way you did earlier.

Incidently, I doubt this voltage reduction is the casue of the non-firing 1 and 4 cylinders.

Just to be up to speed, so the problem is cylinders 1 and 4 are cold at the pipes, but 2 and 3 are hot, correct?

loudhvx wrote:

Just to be up to speed, so the problem is cylinders 1 and 4 are cold at the pipes, but 2 and 3 are hot, correct?

If this is true, you can do some parts swapping on the bike to determine the problem.

First, see if you can swap the coils. That just means swapping the black and green wires, and the plug wires. Hopefully they'll reach. If not, maybe you can swap out the plug wires.

If that makes no difference, there are other swaps you can do to find the problem.