The private pilot/co-owner of the tailwheel-equipped airplane overflew the non-towered, paved airport to determine the wind conditions, which he determined to be from the northwest at about 6 to 8 knots. He then flew a traffic pattern for landing on runway 26, which was 75 feet wide. During the landing flare the airplane began to drift left of the runway centerline, and at touchdown, the tail of the airplane swerved to the left. The pilot unsuccessfully attempted to correct the airplane's path, and then initiated a go-around. He reported that after adding full power for the go-around, the airplane was headed to the right, at an angle that he estimated to be about 45 degrees from the runway alignment. Before the airplane could become airborne, it exited the right side of the runway and struck a low earthen berm. The impact resulted in damage, and the end of the takeoff attempt. The airplane came to rest upright, with the right main landing gear fracture-separated from the fuselage. Additional damage included a bent propeller, a crushed nose cowl, crush damage to the lower fuselage, and bending and crush damage to both wings. Neither the pilot nor his passenger was injured, and both exited via the right-side cabin door. There was no fire. There was no recorded meteorological data for the accident airport, but review of meteorological data from an airport about 10 miles north of the accident airport indicated conditions similar to what the pilot reported. According to the pilot, he had a total flight experience of approximately 2,000 hours, including about 30 hours in the accident airplane make and model in the past 30 days. The pilot stated that there were no mechanical deficiencies or failures that contributed to the accident, but that he was uncertain as to exactly why he lost directional control.