Topic: No spark situation, no juice coming from spark plug wires.

[miketayc]

 I'm new here, I just bought my first bike, a 1975 Honda CB550. I'm not experienced at all with this stuff. I'm kinda at my wits end here.

 I buy the thing, it runs fine all day until it stalls from dropping first gear and won't start back up. Sounds like a dying battery. I leave it alone for a few hours and try again, and luckily it starts up. However, I let it sit for the night and the next day it wont start up. It turns out I left the petcock on all night. I found some fuel under the bike and my oil smelled like gas. I try to start it a few times but nothing. So I changed the oil. However, when I kick start a small amount of gas drips out of the carb overflow tubes. I thought it wouldn't start because of carb issues. I let things dry out. But now I don't know.

I think its becoming an electrical issue. I found out my spark plugs aren't sparking. All the while my battery sounds like its on its last leg. I get a tender, but the battery just can't seem to hold a charge, so I get a new battery. But still no spark. Further more, I tested the cables, and I'm getting nothing. I used a spark plug tester and a multimeter, and I don't think the cables are getting any juice. I tried testing their ohm readings and they show up at 14.5k. Which is apparently correct. It sounds like it wants to start but it just doesn't fire up.

Any help/advice would be appreciated.

Thanks,
Mike

[miketayc]

So I tested the resistance on all the boots, and I'm getting resistance readings in the 200k range except one which is in the 20k range. Is this normal? Could this be the reason why I have no spark to any of my plugs? I find it hard to believe they each individually failed to stop my bike all at once.

[flybox1]

If your plug caps are rated at 5000 ohms, and they read higher than that, they are past their prime and should be replaced.

You could have multiple issues going on there, but it would be prudent to download the shop manual from the site here, and go through all of the 3000mi maintenance items.   Most issues can be remedied by doing so.
If you STILL have issues after all the maintenance items are complete, we can better help troubleshoot.

[madmtnmotors]

So I tested the resistance on all the boots, and I'm getting resistance readings in the 200k range except one which is in the 20k range. Is this normal? Could this be the reason why I have no spark to any of my plugs? I find it hard to believe they each individually failed to stop my bike all at once.

Nope.

Electrical issues often require figuring out what it's not.

>Are all the fuses good?
>Did you test them?
>Have you downloaded the manuals w/wiring diagrams? http://manuals.sohc4.net/cb550/
>Is the kill switch set to the "run" or "on" position?
>Are you now out of fuel?

[Gene]

>Is the kill switch set to the "run" or "on" position?

Don't laugh.  Also, it could be the switch is not working properly.

Follow Flybox's advice, go through the bike maintenance then come back to it.  You may find you have more problems but don't worry, you'll get through it.

[Gene]

P.S. 75 550's are THE BEST!

[miketayc]

Thanks,

It is frustrating. I've been trying to wrap my head around these shop manuals for the past week and coming up a little short.

I tested the coil as shown here: http://blacksquaremotorcycle.com/ignition-coils-test/ . Everything appears to be copacetic.

I'm pretty sure my coils aren't getting any voltage. But I wanted to make sure I was testing it correctly, because I'm coming up with nothing when I test for voltage at the coil on the BLK/WHITE wire, zero.

Switch is set to RUN are KEY is set to ON. A picture of the wire I'm testing in question is attached. This BLK/WHITE striped wire splits to attach to two other BLK/WHITE wires to each separate coil. I place the positive side of mutli-meter into the splitter, and grounded out the negative. And I get zero volts. To further sanity check I put the negative to the BLK/WHITE wire connected to each of the coils in turn and still nothing.

So as you said, I started looking into condensers. I took a picture, because I honestly don't know what I'm looking at.

[Spanner 1]

Wait now !... If you don't have any voltage ( ign. on and kill switch on ) at the black/white wire splitter, you probably do not have voltage at the ign. switch ( Red ). Take out the main fuse and test it for good ( meter on low ohms scale ). Are the fuse connectors shiny clean and tightly gripping the fuse ? With the fuse back in do you have + voltage both ends of it ?

[HondaMan]

Let's go to the root of the electrical distribution: your fuseblock. Under the left cover by the seat is a fuseblock with 3-5 fuses inside the cover. The clips are likely corroded, maybe melted. This will cause the fuses to drop the power, if not kill the circuits altogether. So, clean the fuse clips and see if the problem starts getting better? When they run a while with the 'bad' clips, they heat up until they lose contact altogether, dropping out the main power on the main 15 amp fuse. After cooling off, it works again, sort of, for a while.

Report back what you find there?

[miketayc]

Hey sorry for the late response everyone. I came down with the flu and it knocked me on my ass for the past week. But heres an update. I found out the main issue was with the off/run/off switch. I was a complete barbarian and turned it 90 degrees past its pushing point. It was dark, and I thought the switch handle thing was the arrow that you had to turn to point to off/run. So the clip/spring that connects the switch was just broken right off. I followed the very helpful thread titled:Assembly and Discussion of the Right-hand Switch (a rebuilder's guide). The damage didn't seem irreparable, and I thought I had the switch correctly installed, but nothing. I didn't all without removing the switch itself which seemed much more difficult to do correctly. So I'm running into trouble checking my work. Im trying to find the black and black/white wire that handle the current for that switch to test for continuity, but I'm just getting stumped again. I took off the headlight and it just lead to more confusion. I attached a pic of what I broke for clarification.

i feel like a monster.

[mystic_1]

You monster.

In the meantime, to help make yourself feel a bit better about things, why not run a jumper wire from any convenient BLACK connection to the BLACK/WHITE splitter at the coils, and fire that puppy up!

As regards to your switch, did you loose the little springs and contact plate and detent ball when yours broke?

mystic_1

[miketayc]

No, I didnt lose them. the spring and plate bent, so i bent them back into shape. They seemed to fit nicely back into place, but it still doesn't seem to be working.

[mystic_1]

So underneath that switch is a small circuit board with two contacts on it, those contacts get bridged when the switch is in the ON position.  One of these is the black +12V wire and the other one is the BLACK/WHITE wire that goes to the coils.



The thing I'm wondering about now though is where you said:

I didn't all without removing the switch itself which seemed much more difficult to do correctly. So I'm running into trouble checking my work.

How did you get the little e-clip back onto the end of the switch shaft, if you didn't remove the switch housing from the bars?

Also, to find the BLACK and BLACK/WHITE wires inside the headlight bucket, start by finding the wire bundle that comes from the right side of the handlebars.  In that group you'll find your wires.

mystic_1