Dedicated to the preservation and use of pre 1976 british, european and american motorcycles

Technical Rules

Revised: 20th January 2016

If you are intending to build a machine for NZCMRR events and are not sure of any eligibility requirement please contact the NZCMRR technical committee.

Please click here to download a machine specification sheet which you can submit to the technical committee with any queries about eligibility.

  1. AIMS AND OBJECTIVES. The Register is dedicated to the preservation and use of pre 1976 British, European and American motorcycles.

    These rules are intended to ensure a high standard of authenticity and presentation. All machines must conform to NZCMRR Technical Rules. The Committee reserves the right to accept, or reject any machine which does not meet the standards in keeping with the aims of the Register and the spirit of the classic movement.

    Any doubts or queries regarding eligibility should be addressed to the Technical Committee of the register.

  2. TYPES. Motorcycles which are eligible are those of a model built prior to 1976. No speedway machines will be accepted. Types will be defined by:

    1. Age: Vintage (pre 1931), Pre War (pre 1946), Classic (pre 1963), and Post Classic (pre 1976).

    2. Capacity: Up to 250cc, up to 350cc, up to 500cc and Open (up to1300cc or 750cc. See Pre War rule 16e) Refer to Rule 14.

    3. Group: Clubmans Class, Factory Built Racing Class, Modified Class and Sidecar Class.

    4. The committee reserves the right to run whatever combination of classes it deems suitable for any particular event or championship.

  3. MAJOR COMPONENTS. These will determine age. These are frame and swingarm, engine, fork assembly, gearbox, hubs, brakes, carburettors. No major Japanese components will be accepted in pre 1963 classes.

  4. CARBURETTORS. Must be of the same era as fitted as original equipment. Amal Mk 1 Concentric carburettors will be allowed in post war classes if original types are not available. No flat side carburettors in pre 1963 classes.

  5. IGNITION. NO transistorised, CDI or pointless systems will be accepted in any pre 1963 machine classes, except in pre 1963 Factory Built Racing Machine Class and pre 1963 Modified Class, including sidecars, provided that the original pre 1963 external appearance is maintained. Post Classic Classes are unrestricted.

  6. WHEELS. On all pre 1963 machines, wheels must be of the wire-spoked type and have maximum rim width of 2.15" inside width (MW3). For Modified Class pre 1963 and Post Classic Modified Class, see rules 19 or 20. For Sidecar class see rules 21 or 22.

  7. TYRES. Must be of the type manufactured with tread. Slick tyres or hand cut slicks are not permitted. The use of tyre warmers is prohibited.

  8. BRAKES. On pre 1963 machines drum brakes only are permitted. Refer to various Classes for eligibility.

  9. CLASS ELIGIBILITY. In classes where eligibility is determined by the age of the motorcycle, the year of original availability of the most recently made component (see rule 3 & 11) will determine the class in which it will race.

  10. MODIFICATIONS. Any modifications must be of a type and style in keeping with the class. Modifications deemed outside these requirements will result in the machine being placed in a later or different class.

  11. REPLICA PARTS. Replica components may be used in any proportions provided that they are faithful reproductions of acceptable original components and are not designed to gain a performance advantage. No carbon fibre or Kevlar components accepted.

  12. NUMBER PLATES. All machines must have three (3) clearly written numbers which are allocated by the Race Number Registrar before an event. At the discretion of the Race Number Registrar, numbers will be allocated to members for essentially permanent usage. Any member who remains unfinancial after one year will lose his/her discretionary right to retain such a number, that number being placed back in the pool for redistribution as required. The Register reserves the right to re-allocate a race number which has not been used in the last 2 years. The number plates must be 10" (25.4cm) minimum and 11" (28cm) maximum, round or oval, fitted to the front of the machine and to each side, clearly visible with the rider seated in his riding position. The outline of the number is to be not less than 1" (2.54cm) in width and as tall as practicable. Paint used is to be flat (non gloss) type and colours to be in accordance with the colour code below:

    1. Up to 250cc - Dark green background, white figures.

    2. Up to 350cc - Dark blue background, white figures.

    3. Up to 500cc - Yellow background, black figures.

    4. Over 500cc - Red background, white figures.

    5. Vintage Machines - all capacities - Black background, white figures.

  13. SILENCERS. Exhaust mufflers are mandatory as per MNZ rule. A static or ride-by noise test may be required at some circuits.

  14. ENGINE CAPACITY LIMITS. For engines which retain the manufacturer's bore and stroke, the maximum allowable overbore is 0.060" (1.5mm). For engines with a non-standard bore and stroke the engine capacity must always remain below the nominal maximum for the class entered. i.e. 350cc or 500cc.

  15. VINTAGE CLASS. To cater for machines from the pioneering days of motorcycling:

    1. Motorcycles that are eligible are those of a model built before 1931.

    2. Machines must not have positive stop gear change.

    3. Machines must have pre 1931 major components (see rule 3).

    4. Machines are to be in racing trim.

    5. Fuel. Open (to MNZ rule) - Alcohol permitted.

    6. Flat slide Brown & Barlow carburettors permitted.

    7. Machines must not have hydraulic steering dampers.

    8. Machines must not have hydraulic suspension dampers.

    9. Machines must have ignition systems available within the period.

    10. The gearbox must have no more than four speeds.

    11. Machine must have a maximum of one carburettor per cylinder with a maximum choke size not greater than 1 ¼ inches (32mm) diameter unless fitted to the model as original equipment.

    12. Number plates for Vintage Machines, all capacities - black background, white figures.

  16. PRE WAR CLASS. For machines of a type built before 1946.

    1. Machines must have pre 1946 type major components (see rule 3).

    2. Machines are to be in racing trim.

    3. Fuel. Open (to MNZ rules) - Alcohol permitted.

    4. Brakes. No twin leading shoe front brakes, or double-sided front brakes may be used unless fitted as original equipment.

    5. Capacity. Maximum capacity 500cc ohv, ohc or two strokes and 750 sv or inlet over, side exhaust. see rule 14.

    6. No supercharging allowed.

    7. Machines must not have hydraulic steering dampers.

    8. Machines must not have hydraulic suspension dampers, (except Velocette Mk 8 KTT fitted with oleomatic type rear units).

    9. Machines must have ignition systems available within the period except American machines which may fit early 'Joe Hunt' type magnetos.

    10. The gearbox must have no more than four speeds.

    11. Machine must have a maximum of one carburettor per cylinder with a maximum choke size not greater than 1 ¼ inches (32mm) diameter unless fitted to the model as original equipment.

  17. FACTORY BUILT RACING CLASS. Machines built specifically for Grand Prix Racing.

    1. Machines must have been produced and raced by a recognised factory in the period.

    2. Fuel. Open (to MNZ rule) - Alcohol permitted.

    3. Ceriani G.P. forks only permitted in pre 1963 classes if fitted as original factory equipment.

  18. CLUBMANS CLASS PRE 1963. Machines with major components (as per rule 3) not built specifically for racing:

    1. Lights and stands must be removed.

    2. Exhausts. Road type silencers may be retained but if racing exhausts are used they must comply with MNZ rules.

    3. Brakes. No twin leading shoe front brakes, or double-sided front brakes may be used unless fitted as original equipment.

    4. Gear boxes shall have a maximum of four (4) speeds. Ratios may be varied.

    5. Carburettors. Pre 1963 road or racing carburettors or Amal Mk 1 concentric if the original type is not available.

    6. Fuel. Petrol only, up to 100 octane (R.O.N. rating) Avgas or No 1 Racing Fuel permitted.

    7. Fairings are not permitted. A number plate with 'fly screen', of a type fitted as original equipment to a 7R or Manx, is the largest type of front screening allowed.

    8. Capacity. Engines must retain the manufacturers bore and stroke. Maximum allowable overbore is 0.060" (1.5mm). Effective from 31st May 2004.

  19. MODIFIED CLASS PRE 1963. A modified machine must conform to all the general requirements except:

    1. Engine and gearbox to be the same silhouette as pre 1963 machines.

    2. Frame and suspension components built after 1963 may be used provided they are similar in type and style to pre 1963 components.

    3. Wheels must be of wire-spoked type. Maximum rim width 3.5" (inside width).

    4. Brakes may be later model, provided that they are of drum type.

    5. Carburettors. Amal Mk 1 and Mk ll concentric carburettors will be accepted in pre 1963 open and modified class.

    6. Fuel. Open (to MNZ rule) - Alcohol permitted.

  20. POST CLASSIC MODIFIED CLASS or CLASSIC '70s. A Post Classic machine must conform to all the general requirements except:

    1. These rules will be known as the class rules and incorporate Pre-72 and new Pre-76 rules and are applicable for the 2016 Racing Season.
    2. All models of British, European or American motorcycles of a type manufactured prior to December 31, 1975 are eligible. Later versions of the same models released (but not updated) may be acceptable as eligible when competing in a racing class. (MNZ Pre-72 Rule: 17.1c).
    3. All models of motorcycles of a type manufactured before October 30, 1972 are eligible. Later versions of the same models released (but not updated) may be acceptable as eligible when competing in a racing class. (MNZ Pre-72 Rule 17.1c).
    4. Brakes. Disc brakes are allowed with a maximum of two pistons per calliper. All brake components must be of a type manufactured pre 1976 and follow 17.3a of MNZ Pre-72 Rules.
    5. Electronic ignition is allowed.
    6. Carburettors must be of a type manufactured pre 1976 and follow 17.3f of MNZ Pre-72 rules.
    7. Wheels. Maximum rim width; 3.5" (inside width) are allowable on Pre-76; Pre-72 Rules stipulate a maximum width of 2.5” and this applies to motorcycles other than British, European or American manufacture. Cast alloy wheels are permitted only if factory fitted as original equipment for the individual machine.
    8. Later crankcases of similar design may be used when they provide:
      • Left hand gear change.
      • Greater strength providing they do not change the internal layout of shafts and components or provide any engineering and /or technical advantage other than greater strength.
  21. SIDECAR CLASS PRE 1963. A pre 1963 sidecar must conform to all the modified class pre 1963 requirements except:

    1. Chassis. Separate motorcycle and sidecar type. Either bolted together or constructed in one piece. Tubular construction only, 'sitter' or 'kneeler' type. Engine must be mounted in the motorcycle frame and drive the rear wheel only. Steering head must be motorcycle type only, with telescopic, or twin shock leading or trailing link or a motorcycle system of older design. steering by handlebars only. Sidecar may be on either the left or the right. Wheelbase maximum 1600mm (63"). Wheel track 800 - 1200mm (31.4 - 47.2"). Rigid or twin-shock rear, (no remote reservoir shocks). No mono-shock unless original on motorcycle (Vincent). The sidecar platform must have an unobstructed floor and front exit (or both front and rear). The primary drive must be enclosed and all wheels, chains and belts etc, must be protected above deck level for passenger safety.

    2. Wheels, front and rear, minimum rim diameter 16", maximum 3.5" wide. Side car, minimum rim diameter 10", maximum 4" wide.

    3. Ignition. A handle bar mounted, pull chord operated (rider's wrist), engine "kill" switch which, when operated, disables the low tension ignition circuit and any other electrical equipment (fuel pump) is required as well as a handlebar mounted switch which must be able to be operated easily whilst both hands are on the handlebars (as per MNZ rules).

    4. Brakes. Front and rear must be operated by separate systems. No sidecar brakes.

    5. Passenger grips. Rigid grips must be attached to the frame only (not the bodywork).

    6. Chassis, fairing and general construction must be proven to be of the type raced pre 1963.

  22. SIDECAR CLASS POST CLASSIC or CLASSIC 70's. A post classic or Classic 70's sidecar must conform to the post classic modified or Classic 70's modified class requirements except:

    1. Chassis. As for pre 1963, (see rule 21a) except that the front and rear tyre centre lines may be up to 75mm out of line (parallel). No hub centre steering.

    2. Wheels. minimum diameter 10". Maximum 2. rim width of 5 ½” and maximum tyre width 175mm, treaded type only (no slicks). Cast wheels of a type available pre 1976 permitted.

    3. Ignition. "Kill" switch required (see pre 1963 rule 21c).

    4. Brakes. Front and rear brakes can be linked however at least one front disc/brake must be operated in a separate system by the handlebar lever. Sidecar brakes must operate off the rear brake pedal. Hydraulic systems must have a positive stop for the lever (as per MNZ rule).

    5. Passenger grips. Rigid grips can be attached to the frame or bodywork/fairings but must adhere to MNZ rules.

    6. Chassis, fairing and general construction must be proven to be of the type raced pre 1976.

  23. MACHINE CONDITION. Motorcycles must be presented to the examiners in a clean and well prepared condition in keeping with the aim of the Register. The onus is on the rider to familiarise himself/herself with the rules and present a machine which is in accordance with them. Any alteration made after scrutineering will require re-scrutineering by a member of the Technical Committee.