[5] Castro moved up to Expert Sportsman class in 967 and turned pro novice in 1968[3] Moving up to the Junior category in 1969, Castro was doing well until he broke his ankle playing football with Gary Nixon and Dick Mann at the Triumph factory which side lined him for four nationals.

[3] This prompted Triumph racing boss Pete Coleman to sign Castro for a factory ride in 1970.

[2] Starting in the Expert category in 1970, Castro rode for Triumph in both dirt and road racing events.

[1] Castro and his BSA/Triumph teammates David Aldana and Gene Romero were known as Team Mexican, a tongue-in-cheek reference to their Hispanic roots.

Triumph's road bike sales were suffering with the introduction of superior Japanese machines and the factory cut back its racing budget.

[3] Although he had his race bikes stolen, he did have a Red Line framed 750 cc Triumph twin in his garage.

With the help of Tracy Nelson of The Fiberglas Works in Santa Cruz, California, Castro converted the bike into a streamlined dirt racer.

[3] In 1975, Yamaha ended their factory racing so Castro rode on Kawasakis tuned by Erv Kanemoto.