Classes
A - Experts, 2 or 4 stroke, up to 350cc Pre '70
B - Experts, Over 350cc /Twins / Pre Unti Pre '70
C - Clubman, Any cc - 2 or 4 stroke Pre '70
D - Intermediates - Any cc - 2 or 4 strike Pre ‘70
E - Rigids, Any cc Pre '70
G - Gentlemen, In at Begins, exit at End Card, anywhere in between. (Land permitting)

Machine eligibility – For CLASSES A to G - All machines must utilize engine, gearbox, carburetor, frame, hubs of British manufacture.
Note *FORKS are impossible to police BUT it is important to maintain the silhouette for the period.

Class S - British Built Specials - BRITISH BUILT SPECIALS CLASS ELIGIBILITY
Frames and Engines
Frames must be of original design and copies must follow original design. No re-badged or modified non British bikes.
Alteration of steering angles and foot rest positions is allowed.
Modifications must be in keeping with those made in the era up to mid 1970’s.
Non British made engines only allowed in genuine British made bikes of pre 1970 design ( e.g., Dalesman with Puch engine). NO REPLICAS TO USE NON BRITISH ENGINES.
No mono-shock
Front Forks and Yokes
Any forks 35mm diameter or less can be used provided the silhouette is in keeping with the era. Modern REH forks allowed. No leading axle except for genuine British made (pre 1970) models such as Royal Enfield
Any alloy yokes allowed including billet yokes.
Wheels and Brakes
Any hub/wheel combination allowed provided silhouette is in keeping with the era and up to 150mm dia.
Not Allowed – Disc brakes and non British twin leading shoe brakes.
Carburettors
Any carburettor other than flat slide allowed.
Typical examples of eligible British Built trials bikes:
Cotton Cavalier, Dalesman, Dot, Greeves Pathfinder, Sprite Sachs Goldfinger and Wassell.