had keeway tx125 2015 for 4 months now and when i ride to work in the morning bike rides perfect as am only riding town roads to work how ever if i go dual carriageway once i hit 45mph bike losses power ie slows down to 30mph doesn´t matter if i change down gear still wont speed up pull clutch in and revs fine soon as i get to turn of junction and sit at the lights bike rides fine again, first i fort it was carb related but just fitted new carb and checked for air leaks