‘N evening, the scooter was standing all August in the workshop, where cylinders and pistons were to have been changed, among other things; the engine got from the dealer for the first time 20 w50. After approx. 1,000 km the oil was to be changed; this 1,000 km the scooter drove without abnormalities. On Thursday the engine oil was replaced in my presence by the dealer and again 20w50 filled. On the way home from the workshop it had a piston clamp, resp., I suppose that one was During the ride there was a slight but noticeable jerk and the scooter drove only half of the speed, but recovered after that. On Friday there were no abnormalities. Today on Saturday there was again such a slight but noticeable jerk; this time uphill at 40 km/h with previous “lifting”. In the past, these incidents with the 10w50 had also, but very, very rare. It is to be noted that this “easy but noticeable jerk” in The oil level is just below maximum. Is my guess right that, because “cylinders and pistons new”, the lubrication of the piston does not work properly? Or does the crankshaft, which is still the first one, have a “thing away”, which is noticeable at higher speeds of the crankshaft? Would be conceivable, because unbalances increase as the speed increases? Km per today 92,381 km.