OS have introduced the new OS Speed B2104, a long-stroke .21 offroad engine, featuring quicker response in the low range and more torque in middle range, along with consistent idling. The new piston/liner is conventional 3-port type enabling more torque over the power range, while the new crankshaft has DLC coating and two tungsten counterweights embedded in the crankshaft contributing to consistent idling and quick return to idle. The boost port and the exhaust port of the crankcase are redesigned for optimum air flow, while the rest of the engine remains familiar with the use of 22E type carburettor and…