describe what / how you have tested componants so far?
Have you swapped the coil/plug lead/plug cap from side to side to see if the dead plug swaps side? Have you fitted new plugs? Have you tested the plug caps for continuity? Are you sure its electrical and not fuel related?
More information will help diagnose the issue .
And no 650 engine has a CDI ignition - those little gray boxes are Transistorised Igniters hence the name TI ignition.
Good news at last.....after going down many rabbit holes found someone many years ago looks like me mixed up the primary and main jets....when put in correct positions bike starts and runs great...so great one i Have an MOT have decided to sell it and use the low mileage Deauville for its good carrying capacity.
Of course once I sell iT prices will skyrocket.....always the way...(I sold and NSU sportsmax for £ 75 in my youth !!)
Once sold will leave forum after many years and many helpful responses to my posts...