Hi , my gk73 runs very flat , doesn't rev smoothly when riden ,but idles and revs up fine when stationary.Any ideas ? Thanks

Hi I'm not sure what your problem is, it could either be fueling - blocked main jets that kinda thing or it could be electrical, have you checked your spark plugs?

clean your air filter

My GK73a ran like a bag of cr*p untill I put in a full carb o-ring set in it now it's bang on, common problem so I'm told.