Brian,


In full size engines, stroking is performed by grinding the crank-pins off-center (further out from the crankshaft C/L)and using smaller i/d rod big-end bearings.

If the crank-pin is ground 1 mm smaller, tangentially with its outer perimeter, the stroke would increase by 1 mm, since the center-to-center distance (crank-pin to crankshaft) would increase by 0.5 mm.

...But the crank-pin would also be weakened considerably...