THUNDERSPORT 500 - TECHNICAL REGULATIONS 2010

Everything that is not authorised and prescribed in these specifications must remain in standard form, excluding paintwork.

1.0 Eligible Machines
Honda CB500 1993-2003 Drum & Disc brake Models (CBF model not eligible)
Suzuki GS500 1989-2004
Kawasaki ER500 1997-2006

2.0 Fuel
2.1 Only unleaded fuel, available from a roadside service station to current ACU regulations. E85 bio-fuel is also acceptable from roadside outlets.
2.2 Octane boosters and/or fuel additives are not permitted.

3.0 Bodywork and Screen
3.1 The appearance and dimensions must be as homologated.
3.2 Single seat units or seat covers may be fitted to facilitate the use of race numbers, but must retain the original silhouette of the bike. Seat units specifically designed for racing are strongly recommended and are available from bodywork suppliers (see cb500racing.co.uk for more details).
3.3 Any fairing is forbidden.
3.4 The seat lining may be altered.
3.5 Engine protector pads may be fitted.
3.6 A front number plate/board must be fitted (Maximum W260mm H230mm) and no aerodynamic advantage should be gained. Front number boards designed specifically for racing are strongly recommended and are available from bodywork suppliers (see cb500racing.co.uk for more details).
3.7 The top of the front number plate/board must be mounted so that the top of the plate/board is no higher than the top of the front master cylinder.

4.0 Steering Damper
4.1 A steering damper may not be added.

5.0 Frame/Swingarm
5.1 No alteration to the frame is allowed unless specified in these regulations.
5.2 Frame braising or strengthening is forbidden.
5.3 Additional frame bracing is forbidden.
5.4 The side stand lug may be removed for safety reasons (ground clearance).
5.5 The standard swingarm must be used and remain unaltered.

6.0 Suspension
6.1 Front Forks must remain as homologated by the manufacturer.
6.2 Front Fork springs may be changed for aftermarket items available from Hypapro or Hagon. STRICTLY NO performance enhancing springs and modifications to either springs or damping are allowed
6.3 Front Forks may be positioned in the yokes at any height.
6.4 Only the quantity and type of oil in the front forks may be changed from standard.
6.5 Rear Suspension Units must remain as homologated or be direct replacement aftermarket items (i.e. Hagon), of the correct extended length. Performance enhancing shocks (Ohlins, Whitepower etc) or modified standard shocks are STRICTLY forbidden.

7.0 Tyres
7.1 Tyres are to be Bridgestone BT003S for all Championship races. (Available for £145 per set from the specified supplier TBC)
7.2 Last seasons Bridgestone 090s will be allowed to be used in practice qualifying and races up to July 1st 2010 to allow racers with stocks of 090s to use them up.
7.3 The cutting of extra tread grooves is forbidden.
7.4 Tyres will be examined at random. Anyone not using the correct tyres will be excluded from the championship points and awards.
7.5 Wheel balance weights may be discarded or added.
7.6 If declared a ‘WET’ race Bridgestone wet weather tyres may be used (model as per 2009). (Available for £145 per set from the specified supplier TBC)

8.0 Silencers and Exhaust Systems
8.1 The silencers may be changed. A maximum of 102dBA is permitted.
8.2 Any type of system and silencer may be used as long as the noise output is within the 102db limit.
8.3 The bore of the exhaust headers must remain as standard specification with a tolerance of 5% allowed on aftermarket items.

9.0 Spark Plugs
9.1 Any make and type of spark plug may be used.

10.0 Oils and Fluids
10.1 Any type of lubrication, brake or suspension fluid may be used.

11.0 Safety Wiring
11.1 All drain plugs, external oil filters and bolts that enter any oil cavity must be safety wired.

12.0 Starter / Generators
12.1 Must remain entirely as homologated. Starting devices and electrical generators must operate normally, i.e. the mechanical and electrical connections must be maintained. The generator must charge the battery as normal during the race and at post race control with respect to current and voltage. The engine starting must operate normally at pre and post race scrutineering.

13.0 Airfilters
13.1 The entire air intake system must be as homologated & fully assembled in the correct manor, including air filter element.
13.2 Pattern air filters maybe used provided they are a direct replacement for the original item and offer no technical advantage. No cutting, shaping or other alterations to filters is permitted.
13.3 Performance air filters such as K & N Filters are not permitted.

14.0 Carburettors
14.1Must be the standard units as on the homologated model. A 5% tolerance will be allowed on the main jet size only from those stated.
14.2Carburettor needles must remain as homologated only position may be modified.

15.0 Oil Pipes
15.1Oil lines containing positive pressure must be replaced with items of metal reinforced construction with swagged or threaded connectors.

16.0 Brakes
16.1The choice of brake pads is free
16.2Brake callipers must remain standard.
16.3On the Honda CB500 any combination of original equipment calliper and master cylinder may be used provided they are original Brembo or Nissin parts.
16.3Brake hoses may be changed.
16.4Original equipment master cylinders must be used.
16.5Aftermarket master cylinders are not permitted (e.g. Brembo, AP etc)
16.6Original disks, solid replacement items & floating type aftermarket discs, to the homologated sizes, may be used. (No wavy discs).
16.7Dust seals may be removed.

17.0 Throttle
17.1Throtle control must be self-closing.
17.2Quick action throttles, both complete systems and modifications to the original assembly are not permitted.

18.0 Breathers
18.1All motorcycles must have a closed breather system. No direct atmospheric emission is permitted.

19.0 Number Plates
19.1Must conform to ACU regulations.
19.2Number plates must be fitted to the front and both sides of the machine. (See section 3.0 Bodywork)
19.3All number plates will have a Yellow background with Black numbers.
Note: An alternative colour front number board may be introduced for a Youth category.

20.0 Kill Switch
2.1Motorcycles must be equipped with a functional ignition kill switch or button mounted on either the right or left hand side of the handlebars (within reach of the hand while on the hand grips) that is capable of killing the ignition to fully stop a running engine.

21.0 Footrests / Foot Controls
21.1Original Honda footrests are allowed with riser plates to aid ground clearance.
22.2On original footrests the rear pillion brackets must be removed.
21.3On all makes and models race style rear sets may be fitted.
21.4Standard linkages must be retained.
21.5Quickshifters of any type are not permitted.

22.0 Wiring Harness
22.1Original equipment wiring harnesses must be used.
22.2 Redundant connectors may be removed providing no performance benefit is gained. This can be achieved by either cutting or unplugging.
22.3For neatness & safety redundant & excess wiring should be secured in such away it causes no restriction to machine function (i.e. fork/yoke movement and steering).
22.4If riders wish to run a keyless ignition aftermarket switches may be used in lieu of the ignition barrel.

23.0 Cooling System
23.1Must remain as homologated except the thermostat may be removed.
23.2Only water is to be used in the cooling system (no anti-freeze is permitted as per ACU handbook).
23.3The cooling fan may be removed complete with electrical connections.

24.0 Engine
24.1This must be as original. Any additional removal of material is forbidden. Any engine modification is forbidden. Except for drilling to enable lock wiring.
24.2Ignition systems may be removed at any time by the officials and replaced with standard units or ones from other machines.
24.3The maximum power output for all eligible models is 52bhp at the back wheel.
24.4An oil containment tray to ACU regulations must be securely fitted under the engine. Items designed for racing are strongly recommended and are available from bodywork suppliers (see cb500racing.co.uk for more details).

25.0 Final Drive
25.1Sprockets may be changed from standard to aftermarket replacements.
25.2The pitch of the chain and must remain as standard.
Honda CB = 525
Suzuki GS = 520
Kawasaki ER = 520
25.3The front sprocket on all machines must remain as standard.
Honda CB = 15
Suzuki GS = 16
Kawasaki ER = 17
25.4The rear sprocket on each machine may be changed to a maximum of 2 teeth more than original. Permitted rear sprockets:
Honda CB = 40/41/42
Suzuki GS = 39/40/41
Kawasaki ER = 42/43/44
25.5’O’ ring and non ‘O’ ring chains are permitted.

26.0 Dynomometer
26.1Checks on a dynamometer may be carried out at any time during the meeting the discretion of the organisers.

27.0 Speedo/Rev Counter
27.1The original speedo and rev counter assembly can be removed, retained or modified.
27.2The use of aftermarket rev counters and shift lights is permitted.
27.3The fitment of a rev counter is recommended to aid with noise testing at circuits. No rev counter may result in riders being turned away from noise testing and refused permission to take part in practice and/or racing.

28.0 Handlebars
28.1Both standard and suitable aftermarket handlebars may be used (e.g. Renthal).
28.2Bar ends must be fitted to the handlebars.

29.0 Chain Protector
29.1A shark fin type chain guard must be fitted as per the ACU regulations to the underside of the swingarm on the drive chain side of the machine.

30.0 Wheels
30.1Wheels must remain as standard and with original rim sizes.
30.2 Both drum and disc brake rear wheels may be used.

31.0 Items That Must Be removed
Side and centre stands
Rear view mirrors
Traffic indicators
Front Lights
Rear Lights
Light fittings and left hand switch gear
Horn
Registration plate support
Pillion support bars
Stand handles
Internal gear of the mileage indicator (where applicable)

32.0 Class and Series Sponsors
32.1Class and series title sponsors’ decals/stickers must be prominently displayed on machines where applicable & checked at technical inspection.

33.0 Presentation
33.1 The organisers reserve the right to refuse any machine admission to the start if, on arrival at the technical inspection it is not in a presentable condition.

34.0 Aftermarket Components
34.1Aftermarket parts may be used provided they offer no performance advantage over the original parts, and no technical advantage is gained.

35.0 Parc Ferme /Disputes/Challenges
This is covered in the ACU handbook and minor queries should be directed through the riders’ representatives.

36.0 General
36.1 All riders taking part must acknowledge in writing that they have read and fully understood the regulations prior to competing.
36.2If there are any queries relating to these regulations contact one of your rider representatives for clarification before competition commences.

Rider Representatives:
Matt Bainbridge
email: mattbainbridge82@googlemail.com
tel: 07506 727313

Chris Pickersgill
email: chrisp21@msn.com
tel: 07887 627210

Barry Rudge
email: zuluflipper@yahoo.co.uk
tel: 07899 917180 / 01905 764463

Martyn Smith
email: martyn@hollandcontracts.ltd.uk
tel: 07973 302231