On July 7, 1993 at 2015 hours mountain daylight time, a home built Hummelbird, N2227S, experienced a loss of engine power during cruise flight near Salt Lake City, Utah. The pilot initiated a forced landing in an open field. During the landing roll, the airplane collided with the terrain. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane was substantially damaged and the certificated private pilot was not injured. The pilot reported that at an altitude of 5,600 feet, he pulled the power back for cruise flight. At this time, he heard a loud bang and the airplane began to vibrate. The pilot shut the engine down and initiated a forced landing to an open field. The pilot reported that a Mosler Motors MMCB, reciprocating, 35 horsepower engine is installed in the airplane. Further examination revealed that the crankshaft broke in the web between the number one and number two connecting rod journals.