On August 10, 1995, at 1350 hours Pacific daylight time, the pilot of an Avid Mark IV, N16CN, experienced a loss of engine power shortly after takeoff from the airport at Chino, California. Visual meteorological conditions existed at the time for the local personal flight. The aircraft sustained substantial damage and the pilot received no injuries. The pilot indicated in his accident report that prior to departure he put 4 gallons of auto fuel in the right tank and went through a normal preflight checklist. He departed from runway 21 and shortly after takeoff, the engine began to run rough. The pilot attempted to circle back to the airport to land on runway 26. However, the engine continued to lose power and when the pilot realized he wasn't going to make the runway, he elected to land in a nearby field. During the approach, the aircraft collided with some telephone power lines and came to rest inverted in the field. The pilot stated in his report that he performed some work on the engine prior to the flight. The work included tension and tracking the speed reduction belt, checking the timing (35 degrees btdc at 4,500 rpm), and safety-wiring the propeller. He also indicated that he would never use an auto conversion in an airplane again. He did not state what the specific engine problem was.