Motorcycle Questions? Ask a Mechanic.
Hi, I’m Louie. Sorry you had to wait awhile but I’ll do my best to help.
Initially, proposed preliminary checks (if have not been done):
Bear with me, re-check the wiring including the ground connections to the frame and engine.
The "...over 12v..." would be a phantom voltage; i.e. particularly as the ignition coil is an inductive part.
Additionally, check Ω/resistance of the ignition coil's primary winding.
Possible, but if it were shorted to ground, then the voltage read would be very very low if not 0V.
By design, an ignition coil's primary winding would be low, 1Ω or lower while its secondary would be very very high, ~5KΩ
Appreciate the post back and I would have to be more specific on the ignition coil:
There should be a +12V on the red/white wires to the ignition coil with the ignition switch turned On.
There should be pulsating voltage to 0V on the grey and orange wires to these ignition coils when attempting to start.
If no pulsating to 0V, then check the pickup coils; 650 ~ 700 Ω.
There should be very low pulsating voltage from these pickup coils when attempting to start.
If low pulsating voltage present from the pickup coils but still no pulsating voltage to 0V on the grey and orange wires to these ignition coils, then the TCI is highly suspect.
Let's re-start and check / review the basics, meter set to DCV (say 20DCV if range is available):
Appreciate your patience.
Kindly repeat the above with the ignition switched on.....and then again when attempting to start.
That done and if passed, temporarily hardwire a length of wire from the battery's + terminal to the red/white wires to the ignition coil when attempting to start. Determine if the earlier observation of "...Left coil has 12v and when pressing start button i have 8v. Right coil has 29v (?) Then when pressing start it goes to 36v..." would still hold true.
...and thanks for the update now and again later when able.