D. The POP-skip-POP-skip sounds a little more even on full throttle and full load, but the vibration is serious. The moving mass of both pistons and both rods together is difficult to counter-balance.
1102 Peach Street, Abilene, TX 79602
POP-POP-skip-skip is the distinctive sound of some two-cylinder tractors. My Callahan County, Texas neighbor got rid of a really clean two-cylinder tractor because he said it was missing.
Louis Miller says his 360 degree crank two-cylinder tractor vibrates real badly.
E. Some of the two-cylinder tractors that used 180 degree cranks were Hart-Parr, Rumely Oil-Pull, and John Deere Poppin'Johnny