Hole location varies breath. In motor sport, or duck, mounted breathing hole in the crankcase. But, in the breathing hole automatic motor mounted in the cylinder head. For example, in the Yamaha Mio, breathing holes in the lid mounted cam chain.
In ancient times the motor, breathing hole directly discharged into the atmosphere. Heat or steam heat from the oil directly discharged into the environment. But steam is considered dangerous. Due to pollute the air and its adverse effects on humans.
Because the hot steam from oil-containing pollutants, finally not be dumped carelessly. Especially after Euro rules apply. Steam heat the oil to be recycled. Must be burned in the cylinders used and discarded along the exhaust gases through the exhaust.
On that basis, in the motors now hot oil vapor is channeled towards the air filter. Of the filter will be sucked up by the machine and into the cylinder. Joint air and gasoline vapor eventually burning hot oil in the cylinder. Then out with exhaust fumes. Making steam heat so toxic origin safer for the environment.
Because hot lubricating oil temperature so disposed to make more cool. The pressure in the crankcase also be lower. Making oil seals are not easily broken due to excessive oil pressure. The mechanics are usually put extra breathing holes. Usually additional breathing holes other than crankcase plus from the valve cap from the cap hole and oil revenues.
That's what makes holes in the motor breath arguably adds additional power. Because the engine temperature stable lubricant decreases due to heat. So it is more durable engine and its power out. Some say in the motor can be gained 0.5 hp.
In addition due to excessive heat, the engine power can be increased is reasonable. When the piston up and down in the weight room is not finished crankcase. When the piston goes down, the pressure in the crankcase of the engine so high because of depressed piston. High pressure could reduce the rate of the piston. That is why if you added extra breathing holes make the piston so smoothly up and down and power on up.
In motorcycles, the heat of the oil is channeled towards the tube. Commonly called oil tank paint. There are 4 holes in the tube. A breathing hole of the valve cap, one of the crankcase and one from the oil cap hole. The 4th hole is channeled into the free air.
This tube is not merely function as a heat reservoir. But, as well as safety, when motorcycle falls make oil out of the hole was not breathing and was pooled on the asphalt, but first accommodated in the tube.
