The Rotax VMD is a reed valve direct drive 100cc kart engine (ICA) from Rotax that succeeded the Rotax VMC in 1994. It was the first Rotax reed valve engine with a "jacket" or air guiding wings.
These engines use a right hand side ignition and a closed crankcase half on the left. This construction uses an engine sprocket that is locked against the ignition rotor. These sprockets are difficult to source, but can possibly be machined from standard sprockets.
It was succeeded in 1997 by the Rotax VME.
The Hezemans Rotax 100cc Reed Water Cooled engine is built on this engine's crankcase.