By Julien Pretot PARIS, Feb 1 - International cycling authorities have promised to step up testing for mechanical doping after an electric motor was found in an elite rider's bike, signalling decisive action after struggling for decades to combat illegal drug use. Stewards at the world cyclo-cross championships found the motor on Sunday in the bike of Belgian teenager Femke Van den Driessche, the first such find during a competitive race. "We will be testing more bikes, more often," International Cycling Union (UCI) boss Brian Cookson said following the discovery. More...