no spark

[bigb9582]

ok ive tried searching but could find any help. my 79 standard just lost spark. was ridin it yesterday and it just shut off. cranked it forever and it would sputter everynow and again. then it fired right up and was fine. rode it for another 15-20min and went home with no prob.
go out today and it just cranks with a sputter every now and again. checked the spark and i had none, then it would spark, then none again. did this across all 4 cyclinders.

i dont know what to look for any ideas???

[psycoreefer]

I'd start by checking the advance wires that break under the left side cover, you'll find test/repair instructions under the tech tips.
I would also check that your coils have 12v and that the plug to the TCI box didn't come loose.
Hows your battery? If its cranking slow you might not be getting enough power to the TCI to get it to fire, needs at least 10v. You could try hooking up a battery charger and see if that changes the spark situation.

[bigb9582]

ok here it what i just got done doin. i put the battery charger on the battery while doin this.
i bent,flexed,pulled, and pushed the wires under the cover with no help, even while cranking.
battery voltage never droped below 11v.
while cranking, i did the old spark test by hand holding a screw driver, cyclinders 2&3 no spark at all. but cyclinders 1&4 would spark after i let off the starter button and the engine would sputter. but never start. just one little sputter.
i checked the ohms on the 4 wire plug at the tci box. i think it was the 2 white/?? colored wires had 760 ohms but the 2 yellow/?? colored wires no no ohms. (it could be the other way around i forgot which ones did).

[DiverRay]

You have a bad pick up coil wire. You will need to follow the tech tips to verify what wire has failed. I would also look to see if ANY wire is shorting to ground. If ANY ONE pickup coil wire shorts to ground, engine dies! DAMHIK
I would also check the ballast resistor, and verify it has only about 2 Ohm resistance, not open or over 6 Ohm.

[bigb9582]

ok im gonna go over the wires to check them.
not to sound like a dork but were is the ballast resister.

[bikerphil]

ballast

Take the tank off and it hangs under the left frame rail, close to where the horn mounting bolt is. Just above the valve cover, left front side. Should have 2 red/wht wires.

[XSrunner]

i'm only new and it maybe a long shot but check the engine cut off switch. mine got stuck between on and off on day took me ages to find it .HA!.FELT SO STUPID .

[jeffe]

Even if the exposed pick up coil wires look good you can have a lose wire at the connection between the soft "bendy" pick up coil wires and the rest of the harness. It will be close to where the wire bundel goes thru the case. There is a metal band that is crimped to hold the 2 different types of wires together. I had this come apart on a new set of pick up coils. When I repaired it I left a little extra slack so that there would not be as much pull in this connection. Almost 20k with out anymore problems.

[bigb9582]

well it had both blue and orange wires goin to the top pickup coil broke. they were broke behind the the metel thing that held them back. spliced some wire inbetween them and its good to go.

thanx for all your help.