This is the bike that, unlike any other, fits the description of a dirt-churning weapon. The bike that year after year rocks its rivals, this year comes loaded with high-tech ammunition.The DR-Z's motivation comes from 398cc of displacement, DOHC with four huge valves and liquid cooling. The forged piston is 10% lighter than one conventionally cast, an L-shaped top piston ring reduces blow-by, while copious use of aluminium and magnesium lowers weight and improves heat transfer.