Harley-Davidson's association with sportbike manufacturer Buell Motorcycle Company began in 1987 when they supplied Buell with fifty surplus XR1000 engines. Buell continued to buy engines from Harley-Davidson until 1993, when Harley-Davidson bought 49 percent of the Buell Motorcycle Company. Harley-Davidson increased its share in Buell to ninety-eight percent in 1998, and to complete ownership in 2003.
Whether it is a mechanical, hydraulic, flat tappet or roller style, the lifter is one of the most important components in the engine. The lifter technology determines how the camshaft will react to the rest of the engine combination. And the technology that goes into it is simply amazing.
The DoD system uses an electro-hydraulic actuator device called the valve lifter oil manifold (VLOM) assembly. The VLOM is bolted to the top of the engine valley, below the intake manifold assembly. The VLOM consists of 4 electrically operated Normally Closed Solenoids. Each solenoid controls the application of engine oil pressure to the intake and exhaust valve lifters on the cylinders selected to deactivate. Engine oil pressure is routed to the VLOM assembly from a passage on the rear of the cylinder block.