Born in Nelson, Newcombe grew up in Auckland, then moved to Australia in 1963, and subsequently moved to Europe in 1968. He competed in the 500cc Grand Prix World Championship finishing second to Phil Read in the 1973 season. Along with fellow racer, John Dodds, he developed a motorcycle using a two-strokeoutboard motor designed by Dieter König. He and the König were the first to challenge the dominance of the MV Agustas after the departure of Honda from Grand Prix competition at the end of the 1967 season. In contrast to his main competitors, Newcombe was credited with the distinction of developing, building, maintaining, and riding the König machine in competition. On 11 August 1973, Newcombe was seriously injured at a non-championship event at Silverstone at Stowe Corner. The day before the race Kim did his usual walk around to familiarize himself with the track. He noticed that one particular corner, Stowe, had a dip in the surface right before a sharp turn facing a wall of wooden beams. Concerned for rider safety he approached Vernon Cooper, clerk of the course, about placing hay bales in front of the wall. Cooper was incensed. He angrily rebuffed Kim and threatened him with expulsion from the series if he had the audacity to complain again. The next day, the 11th of August, Kim led the race for six laps before hitting the dip at Stowe, running wide off the track, and striking the wall. Unconscious, he was treated on site before being transferred to a local hospital. Later in the day Cooper suggested maybe they should put some bales in front of the wall at Stowe after all. Kim never regained consciousness and was declared brain dead on August 14. Janeen gave permission for him to be taken off life support and his organs donated. He was 29 years old, and he posthumously took second place in the 1973 500cc Grand Prix, beating Agostini and finishing behind Phil Read. He was survived by his wife Janeen who was supporting him on tour, and their son Mark. Newcombe's story was the subject of the award-winning 2006 documentary Love, Speed and Loss directed by Justin Pemberton.
