[Dave at Pelican Parts]

It's the distance that the piston travels from "full up" to "full down". If the engine is together, measure down the cylidner to the piston top when the piston is at TDC, then rotate the crank until the piston is all the way down at BDC and measure down the cylinder again. The difference is the stroke.

If you have a crank sitting on the bench, then set it against the edge of the bench. Measure the distance from the edge of the bench to the near edge of the rod journal closest to the edge. Then measure the distance from the edge to the near edge of the rod journal that is farthest from the edge. Yes, make sure the crank is lined up as parallel to the edge of the bench as you can. The difference between the two measurements is the stroke.

--DD