The engine in the Jet is “two-cycle” or two-stroke, which means it combines intake and exhaust during the same crankshaft revolution. Simply put, this action makes the device more polluting, which is why two-stroke engines on all but the smallest motorcycles are illegal. The Jet’s 27-cc motor is legal, but eco-conscious homeowners who don’t need to clear large lawns should look to electric models like the Stihl BGA 85.