Leaking from cooling tubes to the head

• The source of this leak is typically the rubber o-rings in the coolant tubes to motor junction.
  • Coolant tube O-rings may be misshapen from the constant compression. But they are standard shaped O-rings.
  • Marginal condition O-rings may start to leak when the temperature gets cold
  • The leak may start after removing the carbs - in the carb removal process, the coolant tubes may have inadvertently shifted
• Coolant tubes are held in place by the O-ring friction and a small "C" clamp in the center of the motor's "V"
  • If the carbs are removed, an 8mm socket on an extension and/or wobble extension will work

  • Pete Staniforth suggests this method for removing the coolant tubes without removing the carbs:

    • Buy a socket head Cap screw that measures 8mm inside the hex across the flats (inside the socket where an allen wrench would go) and approx 18mm long (similar to Mcmaster Carr 91290A514 - I got mine from True Value hardware)
    • Jam 2 nuts on it tight.
    • Invert the assembly to place the head of the Cap screw over the head of the "C" clamp bolt
    • Use a regular open end wrench on the nuts and turn the entire assembly. (crossover bolt/Cap screw and nuts)
    • It's still tight working in there - but if I can do it anyone can..
• Slight prying may be necessary to remove the coolant tube after the "C" clamp is removed. BE CAREFUL! The coolant tube is constructed using thin wall tubing
• Upon removal of coolant tubes, clean the tube ends and motor inlets to remove corrosion. A small application of lubricant on the coolant tube ends will ease the insertion of the coolant tube without cutting the o-ring
• A temporary fix may be to "lightly" tap the coolant tubes in further using a rubber mallet.