Oil lubricating and cooling system for engines

A cooling system for cooling an engine unit including an oil tank device, said oil tank device comprising:

• a head pipe;
• a hollow main tube extending downwardly from said head pipe;
• a hollow down tube extending downwardly from said head pipe;
• a hollow bridge tube connecting said main tube and said down tube;
• and
• frame members covering a space defined by said head pipe, said main tube, said down tube and said bridge tube,
• said main tube being provided with a first oil port communicating an interior of said main tube with an interior of said bridge tube, said down tube being provided with a second oil port communicating the interior of said bridge tube with an interior of said down tube, said first oil port having an opening size larger than that of said second oil port, said main tube being further provided with an oil port communicating the interior of said main tube with said space, said down tube being further provided with an oil port communicating the interior of said down tube with said space, said bridge tube being provided with an oil port communicating the interior of said bridge tube with said space.

An oil lubricating and cooling system for a motorcycle having an engine unit having a cylinder head and a crank case:

• an oil tank for storing oil;
• means including a feed pump disposed in the crank case for flowing a part of the oil from the oil tank to the engine unit for lubrication thereof and for flowing another part of the oil from the oil tank to the cylinder head for cooling thereof;
• means including a scavenge pump disposed in the crank case for flowing oil that has drained to the crank case from the engine unit to the oil tank;
• and
• means for returning the oil used to cool the cylinder head directly to the oil tank without passing through the crank case.