18.6.0.4 Carburettors:
a) Any round-slide carburettor of a type
available pr e-1975 may be used
except the Pre-1960 class where a Mk1
Amal Concentric or period carburettor
may be used.
b) Flat-slide carburettors are prohibited on
all machines except EVO and Pre 85,
c) No reed-valves permitted on machines
up to and including Pre-1970 class
John ,the rules don't actually state which type. I can understand where you are coming from but as Taka says, it needs clarification