Dirt Bike FAQ

2 stroke….has no valves or valve system of any kind. The piston usually has 1 or 2 rings, depending on the model. The spark plug fires on the piston on each and every stroke, plus you have to mix 2 cycle pre mix oil in the gas at a ratio of 20/1 to 50/1, or you will burn it up.

4 stroke…..has anywhere from 2-6 valves per cylinder. Most modern 4 stroke dirt bikes have 4 to 5 valves. 2 being intake valves and 2 being exhaust valves. they have 2 rings, like the 2 stroke, but also have an oil ring. The spark plug fires on every othe stroke, unlike the 2 stroke. Plus the 4 stroke has a timing chain, lifters…..etc….and you can run just gas in them with no oil mixture…..

the 2 strokes are a little more peppy, but the 4 stroke has more torque……

and to answer your other question, YES. if you weigh more, you have to carry more speed on the face and approach to the jump to clear it. Unlike lighter riders that just seem to float over things……