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Superstock 400 Championship

Superstock 400 Update

The Superstock 400 eligibility guidelines have now been drafted and details outlined below.  The class will be identified in the 2021 supplementary regulations for each meeting and given the class number 8f.

As the class develops and entry numbers reach around five per meeting, a Superstock 400 Championship will be introduced, mid-season if numbers rise quickly. 



Overview: Post Classic Junior Superstock is designed for 400cc 4 Stroke and 250cc production-based machines manufactured and raced pre-Dec 1994. For the avoidance of doubt the Aprilia RS250 is not eligible for this class.

CYLINDER CAPACITIES & CUT-OFF DATES FOR POST CLASSIC JUNIOR SUPERSTOCK: Maximum Capacity: 400cc (4 stroke) and 250cc (2 Stroke). See permitted rebore facility in engine section below.

Cut Off Date: 31/12/1994

FRAME: Only the original manufacturers standard frames and sub frames are permitted. Standard parts that bolt to the frame may be removed. E.g. Headlight subframes, centre stands, footrest brackets and lighting brackets.

SWINGING ARM: Must be the manufacturers original fitment to the main frame. Modifications to enable the fitment of wider tyres are not permitted.

FORKS: Forks must be the manufacturers original fitment. Internals free from restriction.

ENGINE: Engines must be in standard specification with the following exceptions.


CYLINDERS may be re-bored to a maximum of 1mm oversize.

TRANSMISSION: Gearbox’s must remain standard. Aftermarket springs and plates may be used in clutches. No form of slipper clutch is permitted

CARBURETTORS: Only standard original fitment carburettors are permitted, unmodified except for changes of jet size and needle type.

AIRBOX: Free from restriction

IGNITION SYSTEM: Free from restriction.

EXHAUST SYSTEM: Must look period and meet the ACU sound limit requirements but is otherwise free from restriction.

INSTRUMENTS and CONTROLS: No digital dashes but digital temperature gauges may be used. After market rear sets can be used.

WHEELS: Wheels may be 16, 17 or 18 inches in diameter.  Wheels must be original fitment or period aftermarket products.

BRAKES: Either manufacturers original fitment or period alternative brakes are permitted. The maximum permitted number of pistons per wheel is 8. Remote master cylinders are permitted, but radial master cylinders are not.  The maximum permitted diameter of the disc is 320mm.

BODYWORK and APPEARANCE: The class will be run as a “Silhouette” class. This means the outline silhouette taken from front, rear and both sides accurately represent the original factory model to the satisfaction of the eligibility officer. Appropriate single seat covers and/or race bodywork in the original dimensions and outline are permitted.

ROAD EQUIPMENT: It is permitted to remove road equipment such as stands, lights, indicators etc.