16.15.11 Acceptable machines and components: Pre 78 Solo
16.15.11.1 Acceptable for the Pre 78 classes:
a) Machines and components that are limited to the 1975, 1976, 1977 models alone. The only exception to this rule is where the model remains unaltered after this date.
b) Pre 78 Women’s class: acceptable machines and components are up to and including the 1977 model year. The only exception to this rule is where the model remains unaltered after this date.
16.15.11.2 Front wheel travel will not exceed 229mm (9 inches) rear wheel travel will be limited to 229mm (9 inches) measured at the axle. Rear shock absorbers will be in the original position using the original mounting points.
16.15.11.3 Engines and gearboxes must remain externally unchanged.
16.15.11.4 Carburettors; any type of pre 78 round slide may be used.
16.15.11.5 Exhaust may be modified but must follow the original lines and meet sound control regulations in GCR 16.12.
16.15.11.6 Folding footrests must be fitted.
16.15.11.7 Countershaft sprocket covers will be fitted.
16.15.11.8 Acceptable follow on models pre 78
a) CZ 125 1978, CZ400 1978,
b) Montesa VB (must comply to suspension limits),
c) Yamaha TT500 1978.
As it is written.
11.3 could be used to prevent w/cooling, but it would also rule out anything from fmf, dg webco ect.
pre 75 is the same, so if there was an alloy swingarm built in '74 that fitted a Honda, then whats stopping it.