Nor did I..Smooth is a funny term..Smooth to one person is rough to another..
Direct quote from the DA owner's manual.."Beware of running the motor without the wings installed on the fuselage.Without the mass of the wings, vibration will be very pronounced"..
The DA and Poulan were run on a Black and Decker Workmate with a 2x1o bolted vertically on the top..They both shook, hard to tell any difference...A single cannot be balanced, it's physically impossible...Some are smoother than others..You want smooth, get a twin...Smoothest single I ever had was a 42cc Red Max converted brush cutter, had a heavy crank like a G62..Engine weighed 4 lbs...
Light switch transition ? Right...2000 rpm to 6000 rpm instantly, one click of the throttle..
Rough ass ? Engine finish or imagined vibration level..
The cast finish on the Poulan case is smoother than the machined finish on the DA..A few more passes with the milling machine would make it smoother, but time is $$ on a CNC machine...
Have a nice day, RCIGN...
I REALLY like the DA50R, but for $350.00 LESS ( I make my own ignitions) I'll take a Poulan...