Radiator These radiators are nearly 30 years old. Take them to a reputable radiator shop and have yours cleaned. Your bike will love you for it. Cooling system Apparently, if the water pump fails, you can replace it with the engine still in the frame. Consult the magazine Classic and Motorcycle Mechanics or any of the Waterbuffalo or Kettle resource web pages.
Thermostats do fail and can lead to big problems.
Replace those hoses as well. Once again, electric is better than breaker point. Kawasaki bikes can be made to fit with a little modification. Pipes Tend your baffles or they will go away. This is a current problem with my 72 and I ve looked for a number of years for a replacement.