Most commone problems that you may Not have already thought of are.
1. Bad safety switch in the SEAT. Also known as a dead man switch. If you fall off, it kills the engine.. It may need replaced because it shuts off the spark by shorting the coil out. Just like turning the key off..
2. And of course that means it could also be a bad ignition switch.
3. It could also be ANY wire that connects any electrical component in this part of the electrical systm.
It coul dbe worn and shorted out.
I have never seen a unit that was NEW enough to have a breakerless ignition that did not have safety switches. Has someone taken them OFF, or could one be hidden INSIDE the seat?
Did you check the ignition switch?
Do you have a service manual for your engine? Have you done all of the tests per the service manual?
I have provided a link to the owners and service manual for this engine.
You may download it for free at
Perhaps it will be helpful to you.
This unit was available with both magnito in its early years and breakerless ignition later on.
You may wish to use it as a helpful guide to go through to help troubleshoot.
See attached link for the service manual. Go to section 8. It will give you the instructions for using a meter to test the trigger and the coil. Make sure you have the trigger leads wired up correctly.