I worked for a Hatz dealer once. We rebuilt the 6/8hp engines under contract to the military. I had to test run them after rebuilding. They produce a ton of torque. To start the rings seating you had to load them, the common practice was to wedge an oak 2x4 between the test stand and the exposed flywheel to produce a load. I had a good deal of leverage with a 4' board. You couldnt choke em at high throttle, it would just burn up the 2x4. The down side is they were noisy, vibrated badly unless on a very well dampened/engineered mount., and dont throttle as smoothly/rapidly as a gas engine. They do best in a constant load situation. It does get better the more cylinders. The little 3cyl Kubotas we sold were very smooth and tractable. I have seen a M/C or two with the diesel in the link installed, IMHO I think it to be more of a novelty than practical. I still have one of the Hatz engines if someone wants to give it a try. Cranking it will draw a crowd as it uses a hand crank.
