Won't start, no spark at plugs

pablohoney · Posted: October 1, 2009, 10:42 pm Post subject: Won't start, no spark at plugs

I just got my bike back together and it won't start... big surprise.

The plugs aren't sparking and I have no idea how to test anything. I am very bad at this electrical stuff, but I do have a tester, so if anyone could tell me where start and how to do it, I would be your best friend. Thanks.

xsleo

With your tester start checking for 12 volts at the coil. follow the wires from the coil back toward the battery until you find 12 volts. At where ever the 12 volts stops is the problem. A connection, a switch , a fuse , a broken wire. Keep checking you will find it.

kingwj

Were the 79 specials points bikes or electronic? I know my standard has points.

pablohoney

It has points, I'll get testing.

yamaman

How back together did you have to make it?
If the engines been out, problems can occur with the earth from engine to frame. Put a jumper lead from the (make sure it's fully charged) negative battery terminal to the engine, see if that makes a difference!

pablohoney

It has everything on but the side covers, and the pegs. I''l try that.

I took all the fuses out, turned on the ignition and tested the holders and only one of them showed voltage. The one with the two red wires.

pablohoney

I pulled off the spark plug cap and stuck my tester in the wire and on both I got 12 volts. If the condesner isn't hooked up would it make it not spark? I didn't know that is what it was and I can't see where the two black wire hook in to.

pablohoney

I hooked up the condenser correctly and gapped the points and it still won't spark. Any ideas?

gordo

Pablo, no, I'm not gonna to call you honey. Try doing a continuity test on the coil's. Where the small electrical wire's go, test for continuity there. Meter on the lowest ohm's scale, like 200. The reading should be about 3-4 ohm's. Then from each of those terminal's to the center of the coil, where the plug wire goe's. Reset the meter to 20,000 ohm's, and the reading should be about 25. If either of those are out, the coil's are bad.Also, one of the small terminal's should have battery voltage, & the other side will vary, point's open, voltage, point's closed, no voltage.That should be the negative side of the coil. You can check the wiring from the negative side of the coil to the point's also with the ohm meter.That reading should be close to 0 resistance. You did say you have battery voltage on one side, correct?Keep at it, & post your question's, if any.

pablohoney

Ok, I am an idiot, the contact point cam lobe was in backwards.
DOH!! Now it sparks. Thanks guys.

kingwj

They should all be so easy.

scout18

This thread is coming in handy. I have voltage to the coils and to the points but no spark at the plugs. So my values are a little off what you list Gordo but within a few ohms seems ok. I tested one plug wire and it is about 6 ohms. So I clipped a little off the end until I had new wire, put it back together and bingo left side has spark. Now for the right side...

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