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Today’s Dirt Bike MotorsThe evolution of dirt bike motors has come along way since the first 2 strokes built by Honda and Kawasaki. In the early 50’s the 2-stroke engine was the main type of motor used in motorcycles as well as many other products requiring small engines. The 2-stroke which requires oil to be mixed in its fuel was inexpensive to build with far less moving parts than today’s more popular 4-strokes. There simple design requires a simple reed valve system to allow the air fuel mixture to enter the combustion chamber. 
With 2 complete strokes between firing this type of engine was preferred in many racing applications due to there higher RPM capabilities. One drawback, however, is a bit more pollution due to the lubrication oil which needed to be “pre-mixed” into the fuel. Another was that at certain RPM ranges the rider would experience a huge rush of power. This rush of power, although sometimes good for racing, creates a much different riding style and can be a little tricky, at times, to manage!
We're Going Green!As the global push towards going “green” becomes more of a factor most of the motorcycle manufactures are starting to phase out there 2-strokes and put there engineering efforts into the lower revving 4-stroke. In fact, the 4-stroke is now the more popular engine in the motorcycle racing world. With gobs of power and a smoother more manageable power curve, the 4-stroke is now the more preferred engine choice in Motocross and Supercross racing.The 4-stroke uses a valve system operated by a camshaft, which typically sits over the top of the cylinder, and has 4 strokes between firing rather than 2. With oil in the crankcase, rather than in the gas, a 4-stroke requires an oil pump to get the oil up to the valve train and all its moving parts. All these extra components make the cost of a 4-stroke considerably more than 2-stroke dirt bike motors, but they are cleaner burning which is better for the environment.
We, or I should say my son Zach, can speak from a racing point of view. He graduated from 2-stroke Mini’s in mid 2007 to a 250F 4-stroke Honda and hasn’t looked back since. He likes the more manageable power curve and claims it allows him to focus more on riding correctly rather than managing a big hit in the power band when he’s on the gas! Return from Dirt Bike Motors to DirtBike411 Home
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