DKW SS/UL Split Piston supercharged two stroke. A 5 piston, twin cylinder....
"For larger capacity classes a twin cylinder version of the UL was developed, and these motors were available in 350, 500, 600 and 700cc displacements, with the three latter capacities (some with multiple Ladepumpe pistons) reserved for sidecar racing. Unlike the ULe and ULd 250, the Ladepumpe was once again moved to the 180 degree position and driven off the main crankshaft with a pair of conrods. Thus these “twins” had five pistons: four 39.5mm items, plus the 100mm supercharging piston, all held together around a common crankshaft by six conrods. The cylinder block had the appearance of a square-four, and were distinguished from the 250s by their finned water jackets and the 180 degree placement of their Ladepumpe cylinders. A SS 350, which was virtually identical to the works UL machines, was offered to the public and sold in limited numbers." -
http://www.odd-bike.com/2014/02/dkw-sup ... e-fed.html
