Author Topic: No spark?  (Read 405 times)

0 Members and 1 Guest are viewing this topic.

Offline jon baker

  • Full Member
  • *
  • Posts: 4
No spark?
« on: May 22, 2016, 03:19:36 AM »
Hi all, i am having trouble getting a spark. I have noticed that if i kick the bike over with ignition on no spark but if i flick the kill switch on and off the plug will spark? anyone got any ideas?

Offline mystic_1

  • Really Old Timer ...
  • *******
  • Posts: 6,071
  • 1970 CB750K
Re: No spark?
« Reply #1 on: May 22, 2016, 05:38:01 AM »
Spark is generated by feeding power into the coil, then cutting the power.  The pulse causes the magnetic field in the coil to grow and then to shrink, and the movement of this magnetic flux through the coil's secondary winding is what generates the spark itself.

Flipping the kill switch on and off has the same effect as the point opening and closing, so it's no surprise that you get a spark when you do this, and it would seem to confirm that you have power to the coils and that the coils themselves are working.

If you're not getting spark when kicking the motor over, I'd be looking at the point, condensors, and their associated wiring.

Did you work on the points plate at all?  If so, are you sure you got all of the connections in the right places?  Post a picture of your points setup if you can.

mystic_1
"A ship in harbor is safe, but that is not what ships are built for."
- John Augustus Shedd

My build thread:  http://forums.sohc4.net/index.php?topic=68952.0

Offline jon baker

  • Full Member
  • *
  • Posts: 4
Re: No spark?
« Reply #2 on: May 22, 2016, 05:52:26 AM »
Thank you for your replies, my bike has electronic ignition on it so i will trace the wires and check connections.