Harley Davidson Motorcycle Engine Vents

Four-stroke engines need ventilation. As soon as they are cranked, the working temperature is still low, creating combustion byproducts and condensation within the crankcase. Engine vents allow the circulation of air and keep the engine clean. But there is another reason for their use related to the construction of motors. Atmospheric pressure and a small percentage of combustion gases reach the crankcase even in the most perfect motors, creating a dangerous internal pressure that could cause all the seals to break. Vents and breathers are designed to maintain the pressure in the crankcase within the set limits.

In large motors, such as those installed in Harley Davidson bikes, most extra pressure is caused by the phenomenon known as blowby and by malfunctioning pistons. When they are worn out or not placed properly, they cause damage to the piston rings, which can no longer seal the combustion chamber. Breathers and vents trap fuel vapors and water preventing the pressure in the crankcase from reaching an alarming level. Browse our online store to find a large selection of Harley Davidson motorcycle engine vents and related components, including bolts, filters, and fittings.