A Kohler man was seriously injured in a motorcycle crash in Fond du Lac County. The crash happened Saturday afternoon on Highway 67 near Boy Scout Drive. A preliminary investigation indicates the motorcycle was northbound on 67 when it had a mechanical problem and crashed into a guardrail throwing both occupants. The operator, a 65 year old Kohler man, was flown by helicopter to a hospital with serious injuries. The passenger, a 57 year old Kohler woman, received minor injuries. Neither occupant was wearing a helmet.