by greg mcewen #580 » Tue Oct 27, 2015 6:23 am
From "the book"
The following examples and exceptions, when fitted with drum brakes, are permitted in Period 1.
Aermacchi (Harley Sprint) Any road-based 250 or 350cc four-stroke single up to and including 1974 BMW Rennsport and /5 models (Maximum displacement 750cc)
BSA 441 & B50 (no 4-valve heads will be permitted), twins to 750cc
Bultaco - all motor and bike models through 72
Ducati singles
Greeves Silverstone
Harley-Davidson KR, ER, and CR roadracers
Honda CB/CL/SL 350cc with drum brakes (see note above), CR, CB, and CL twins to 500cc
Jawa - 2-valve, four-stroke single cylinder speedway engines through 1978. No overhead camshafts permitted. The engine must be mounted in a period frame, and must not use total loss engine lubrication. Laverda 750 SF
Montesa - all motor and bike models through 72
Norton 750cc Commando
Ossa - all motor and bike models through 72
Rickman CR Road Racing chassis powered by H-D CR or ER, G50 or 7R
Royal Enfield
Seeley G50 or 7R
Suzuki T250, T350 & GT 250 (with Ram-Air removed)
Triumph twins to 75Occ
Velocette
Yamaha TD-1C
Thanks to Kennedy motorsports http://www.kennedymotorsports.com