Having just recently completed an engine rebuild on my 750A, "DTW" is right!
Head can come off with engine in frame, but cylinders cannot. Engine must be removed from the frame in order to remove cylinders.
Engine can be removed by laying the engine/frame on its' side method or "HackaWeek method" (on YouTube) can be utilized. I tried the "HackaWeek method" and it was easy.
One 2 x 4 and two strong neighbors!
Hope this helps!