Motorcycle Repair: spark plug wires, air fuel mixture, cylinder compression

Question
  I just bought a 1979 Yahama 650 and it ran fine for a couple of days.  Now it won't start, I replaced the spark plugs and it is getting gas, it might be the spark plug wires but I am not sure if the whole coil has to be replaced or just the the wires and informatin you could give me, as well as some other ideas that might be causing it not to start would be appreciated.
        thanks
        Heath

Answer
Hi Heath,

An engine needs three things to run: adequate cylinder compression, a spark at the right time, and correct air-fuel mixture.

The problem could be a variety of possibilities. I would need to see the sark plugs to start. Is it have points or electronic ignition? I would check battery condition; is there power to the ignition switch and coil primary windings? Is the carbs varnished from storage or non-starting? Are the plugs capped tightly screwed onto the HT wires? So many things to check.

If I had an email address for you as requested, I would have returned repair info files. Also need model of MC.

Respectfully,
Mark Shively