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Formula 250 National

This class is nominated by the MSA to be the 2007 British Superkart Championship class and is administered by the British Superkart Association for the period 2007, 2008 & 2009. The engines in this have to registered for a three year period.

Chassis

Any chassis complying with MSA Regulations for gearbox karts. All chassis main parts must be firmly securely together on to the chassis frame. Flexible connections are only authorised for the conventional steering knuckle support, and for the steering system . All other devices with the function of one, two or three dimensional joints are forbidden. The chassis frame is the central and main supporting element of the entire vehicle. It must have the necessary strength in order to be able to absorb the loads which are produced when the vehicle is in motion. Any hydraulic, pneumatic or elastomeric elements for damping chassis oscillation are forbidden. Minimum wheelbase is 106cm.

Engine

Eligible engines are as follows :

Tuning Regulations

Modifications to the engine are allowed, provided the following are not varied.

The ignition system type is open BUT the electronic unit box and the coil must receive only one feeding energy source of the rotor/stator or of a battery and one crankshaft pick-up signal in order to set the ignition signal. The advance and cartography may under no circumstances be modifiable from the driving seat under normal racing conditions.

Transmission.

Plates

White number plates with black numbers.

Age

The class is open to any driver aged 16 or over on short circuits and aged 17 and above on long circuits. A novice driver may compete on short or long circuit (only at closed to club or National B events).

F250 National Superstock 

This class was granted an N1.3 by the MSA to run as part of the BSRC Club Championship whilst the class develops until such a time as it is strong enough to stand as a Nationally recognised class in its own rights.

The technical regulations are the same as those for F250 National above but with a specific Honda engine and these specific engine regulations.

Engine

The aim of the series is to provide competitive racing with good engine reliability, reasonable service periods and costs. To this end modifications are limited. The cylinder head modifications allow economical inspection (due to O-Ring sealing) and easy replacement of the combustion chamber in the event of damage.

It is anticipated that competitors wishing to compete in this category will wish to enter into the spirit of "fast, economical and fun motorsport" and that there will not be any tendency to "bending the rules" or indeed outright cheating.

However, the motor specification is formulated to allow quick and easy inspection by an eligibility scrutineer.

Engine/Gearbox

  1. The motor is based on Honda CR250 Series Production Crankcase Induction Motor manufactured between 2002 and 2004 inclusive. Based on CIK Fiche No. 12/SKM/05
  2. All engine castings must be the originals of O/E manufacture and unmodified apart any allowable modifications detailed in the following.
  3. A Viper Racing UK aluminium cylinder barrel spacer plate must be fitted. Part number: VIP/SS/01. One base gasket of Honda O/E manufacture (nom 0.5mm thick) must be fitted either side of the spacer plate
  4. The kick-start mechanism and kick-start idler gear may be removed if desired, in which case a secure blanking plug must be fitted to the clutch housing to prevent oil leakage.
  5. A Viper Racing UK supplied 2-piece cylinder head is mandatory. The head insert regulates the combustion volume and squish band, which is fixed. The part number of the complete head is: VIP/SS/04
  6. Cylinder Head Nuts can be replaced with Dome Nuts and Brass Washers.
  7. Original Honda Crankshaft must be used. Crankshafts can be rebuilt using either Honda O/E or Prox (Part No. 03.1322) Con-Rod kits.
  8. O/E or Pattern Clutch friction and plain plates can be used.
  9. Piston must be 2-ring type of either O/E or Prox (Part No. 01.1322) manufacture.
  10. No other changes are allowed to the internal components of the engine/gearbox and clutch.
  11. Positioning of the pulse take-off is free.
  12. The standard cylinder barrel must have no modifications whatsoever. Any machining, polishing or removal of material from the cylinder barrel, it's ports, etc. is prohibited.
  13. Standard power-valve flaps must be fitted and locked open by means of bolts/locknuts through the original cable channels in the side, or alternatively through the back of the power-valve pulley housing. It is also permissible in addition to bond the flaps open with epoxy adhesive or similar between the tops/sides of the flaps and the cylinder casting. The epoxy can be used to fill any small voids between the power valve flaps and barrel, but not to reshape ports, etc in any way. No machining is allowed.
  14. Max bore size permitted is 66.36mm (Grade C).
  15. Total swept volume cannot exceed 250cc
  16. A CIK approved airbox must be used, as per F250 National. A foam filter may be added to the airbox
  17. All engines must be sealed between Cylinder, Crankcases and Exhaust Stub. The Ignition Stator Mounting Bolts will also be sealed. The engine must be presented at Scrutineering with the official seals intact. The sole sealing agent that is authorised to seal engines is Ian Harrison of Viper Racing UK. If for maintenance reasons the seal has to be broken then the seal (s) must be replaced by Ian Harrison before being used in competition again. The Eligibility Scrutineer is permitted to remove the seals in order to check validity but those seals must be replaced before competing again. Ian Harrison will be present at all of the series rounds.
  18. Carburation and Induction
    1. A Viper Racing UK supplied hand finished, polished and jetted Dellorto 39VHSB carburettor is mandatory.
    2. Jetting is as follows:
      • Fuel cut-off valve: 170
      • Tube: DQ269
      • Needle: K44
      • Needle Clip Position: Free
      • Pilot Jet: 55
      • Main Jet: Free
      • Pilot Jet Emulsion Tube: 38
    3. The O/E reed block and reeds must be used. A Viper Racing UK supplied adapter plate Part No. VIP/SS/12 and induction Rubber Part No. VIP/SS/13

Ignition           

  1. The ignition system must be PVL analogue. The part number for the complete system is VIP/SS/05. Individual Part Numbers allowed are:
    • Viper Modified PVL Stator – VIP/SS/51
    • Special PVL Rotor with keyway – VIP/SS/52
    • Standard PVL Coil – 458 100
    • Viper PVL Mounting Plate – VIP/SS/06
  2. No other parts are allowed in the ignition circuit
  3. It is permissible to remove material from the ignition housing to accommodate the ignition system.
  4. If required to do so by a Senior Licensed Official of the meeting a driver must fit a Reference Ignition system, which will be supplied to him/her

Exhaust           

  1. Exhaust mounting stub must be Viper Racing Supplied. Part number is VIP/SS/08
  2. Expansion chamber must be Viper Racing Supplied Superstock Item. Part Number is VIP/SS/09
  3. Connecting Pipe and silencer are free (Noise levels must not exceed limits set out below)

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