[1] Shepherd was a three-time winner of the North West 200 race in Northern Ireland and finished on the podium twice at the Isle of Man TT.
Despite competing on a limited budget, Shepherd managed to win the season-opening 250cc United States Grand Prix, held at the Daytona International Speedway then, placed second to Honda's Jim Redman at the Isle of Man Lightweight TT to finish the 1964 250cc world championship season in third place behind the powerful Yamaha and Honda teams represented by Phil Read and Redman.
[8] Shepherd retired in 1965 after recovering from a head injury suffered in late 1964 when testing a works Honda in preparation for the 1964 Japanese Grand Prix.
He told Motor Cycle's David Dixon in June 1965 that – whilst he felt fully recovered – he no longer had the confidence to be a top-runner, and would not ride Hondas unless he could give the best possible performance.
[9] He died peacefully at Summerhill Nursing Home, Kendal, Cumbria in July 2007, with a funeral service at Cartmel Priory followed by cremation at Lancaster.