According to Canned Heat drummer Adolpho "Fito" de la Parra, Vestine frequently used methamphetamine and heroin during his tenure with the band. Combined with other band members' substance abuse, this created difficulties for the group. During this period Vestine also developed an intense interest in Harley Davidson motorcycles. He eventually owned eleven of them. Prior to his death he was looking forward to playing at their 75th Anniversary Celebration. Over the years he had also a close relationship with the Hells Angels.