1971 CT1 175.
No spark. What I've done so far:
Original owner could never get a spark and gave up. 2nd owner could not get a spark and gave the bike to me. ( Oh Joy )
I obtained a flywheel puller and found All of the wiring from the Source Coil and the Charging Coil were shorted to ground at the flywheel points-plate.
I repaired the wiring and checked out both coils at the flywheel and both have the Ohms you'd expect to see.
The points were cleaned, filed and adjusted for a proper gap but not pulling the head and using a dial indicator for the 2 degrees BTDC.
The Source Coil is putting out 16 VAC at around 75 RPM using an electric drill to spin the engine. The Charging coil about 8 VAC.
I by-passed all of the original wiring to the ignition coil and ran known to be good jumpers from the flywheel magneto to the ignition coil.
The 16 VAC is producing an out put of 300 volts. Not enough to do anything.
What I cannot find in any manual on-line is what is the "normal" output of the Source Coil when the engine is kick-started or turned with a motor?
I can only assume the 16 VAC is way too low to cause the Ignition Coil to generate a spark voltage.
The condenser test out OK. ( charges / discharges )
Thank you for any helpful info.

You asked this same question before and I never saw a response.  See  yamaha-enduros.com/index.php/forums/1968...output-at-crank-over