Motorcycle Repair: 1974 yamah 250 enduro, electrical problems, spark plug

Question
Bike had been sitting for about 5 years before I got it.  I put a new battery in it and cleaned the carb.  it started right up and ran for a few minutes then stopped and will not start.  I checked and it has no spark. What should be done next?

Answer
Electrical problems can be a pain.Is this the same spark plug or did you change it out also? There could be a bad connection or as simple a replacing a spark plug. On the worst side of it the crank seals can dry out and cause a vaccum leak not allowing it to draw in fuel.