Manufacturing tolerances can make a slight difference when the engines are assembled...End play is not a big problem...It can be taken out with a shim under either bearing in the case or using thin steel washers between the crank and bearings...Zenoah makes crankshaft shims for some of the weedeater and brushcutter engines, and some of the G62s a while back..Haven't seen any in the newer ones...[8D]