Hmm, a new no-spark, first cheapest fix, is to take off the wires from both the coil, and the plug. Cut off 1/2 inch (10 mm) of wire, from Both sides. My theory is that one or both sides, have been tarnished to the point of it no longer works. (unsubstantiated) By cutting out the 1/2 inch, you will put the spike/screw into new fresh wire.
(get new plugs/wire/caps. last time I got them from my local yamaha guy, for just over 10bucks. (2 plugs, (listed in my signature) 2 to 3 feet of wire. and I would suggest the NGK 5k resistor caps. if you can't find just get what you can.
Then if you still suspect no spark, be carefull of testining with out the spark plug in, the manaul clearly warns that you can destroy your TCI.