Topic: grrrr, no spark...

[verboten1]

Soooo.

I have (weak)  spark out of the coils when I put them on the 12V power supply and cycle power to them.

my points seem to make and break contact as I have 12V on them when open, and < 0.5V when closed

I have thrown a wire directly to 12V to the coils, spin engine and still no spark.

coil primary measures 4.7 and 4.9 ohms
secondary 14.6 and 14.7 ohms
so the coils appear to be in spec.

old caps were way out of spec, so I replaced them.

I don't really have the money to buy new coils, cant seem to find any good cheap used ones either.

The ignition system is so simple, I don't understand how I can't seem to make this work!!



*edit* I searched and read every thread in here about no spark, tried many of the solutions.....I am confused!

[OldSchool_IsCool]

When you check for spark, are you grounding out the plug to the motor or are you using a spark tester of some sort?  Do you have full 12v or more at the black/white wire of the coils?

[verboten1]

with the original wiring I had 9.7 V I ran a new wire just to test, had 12.1 V at the B/W wire.


With the coils on the bike, I was grounding a plug, with the coils off the bike, I put a nail in the cable and checked for spark to each other

[Spanner 1]

As I understand it, the iron core thru' the coils must be grounded ( as when mounted on the bike ) for correct coil operation......

[verboten1]

they are back on the bike, and grounded once again, but the only time I have seen spark is when i had them off the bike, with no ground, and even then it was weak

[OldSchool_IsCool]

Measure the resistance of the blue and yellow wires from the coils to the points.  Are you seeing resistance of more then a few ohms?

[verboten1]

the wires are in great shape, 0.8 Ω and 0.7 Ω


thanks for your help so far!

[OldSchool_IsCool]

Try to clean up any connectors (bullets and blades) on the blue and yellow wires.  Consider that the coil primaries are around 5 ohms, the wires are adding 10 to 15% more.  That's not even considering any voltage/current loss from the black/white side of the circuit.

[Spanner 1]

Also the plug bodies would need to be connected together for spark.....or both laying on the head, if coils are back in the bike........what 'power supply' are you using?, would need to be 12v @ 5 amps, minimum..........