Regs
GX-UK (Senior and Junior)
2025 Technical Regulations
A1. Introduction: - GX-UK Is a race series built around the Honda GX160 and GX200 engines and a wide variety of otherwise, underutilised chassis’ in order to create a low-cost way to enter owner karting.
The class ethos is to allow all competitors to race competitively with longer life 4 stroke engines, stable class regulations and on a minimal budget.
Whilst the spirit of competitive racing is being embraced, certain concessions to more broadly used regulations have been implemented with the sole aim of reducing costs, whilst also opening up the class to as many competitors as possible.
The Series Organisers reserve the right to amend the regulations based on safety at short notice.
Minor clarifications to the regulations can be made with 4 weeks’ notice from affect and will be
published on the GX-UK Facebook Page and the Access Karting website (www.accesskarting-uk.com).
Any major rule changes such as, tyres, significant weight limit and chassis will only be done in
between a championship finishing and the next commencing unless subject to force majeure.
The GX-UK classes runs within the sporting regulations utilised by Access Karting, an IKR host. This will be made clear before each meeting.
In any scenarios when the GX-UK regulations are, or could be viewed as ambiguous the MSUK Honda cadet engine fische shall override.
A2. Engine
A2.1 All engines are to meet the standard sealed RPM spec or to the MSUK spec fiche. Replacement engine parts that are like for like and must be original Honda manufactured. Front Sprocket sizes open and does NOT have to be a Honda original part.
A2.2 all engines are to run a clutched with a pull cord starting mechanism.
A2.3 engines are to be of the original stamped cc volume, either 160cc or 200cc.
A2.4 fuel tanks can be mounted on top of the engine as sold as standard or removed and placed around the steering column in the more conventional karting layout.
A2.5 Maximum of 2 engines per entrant to be signed on per race day, these serial numbers must be submitted in advance of them being raced by any competitor.
A2.6 Competitors engines must meet one of the following sealing standards for 200cc engines
200cc restricted – RPM blue seal or the Access Karting Green seal via Monkey Motorsport
200cc unrestricted – RPM red seals or the Access Karting Yellow seal via Monkey Motorsport
A2.7 Each competitor will be allocated a maximum of 3 seals per season, these can be allocated over a single engine or up to 3 engines as is the preference of the entrant. The only instance that more than 3 seals will be allocated is if the competitor can demonstrate material damage to the engine to an official of Access Karting. (numbers of both the RPM seals or Access Karting seals will be tracked by the series)
A2.8 External repainting of barrel and head allow for aesthetics – outside only.
A2.9 Engine mount may be aluminium, steel or magnesium
A3. Airfilter and box
A3.1. Airboxes and filters must conform to the standard shape and position as they are when sold and cannot be modified.
A3.3a. No drilling of the airbox or filter is permitted with the exception of fitting a bracket for the oil overflow catch bottle, these cannot then be left exposed if the bottle is removed.
A3.4b Air Filter must be intact with all the relevant elements present as per the MSUK Honda Cadet fische
A4. Carburettors
A4.1 The only permitted carburettor is the standard Honda carburettor as supplied as standard as per the fisch.
A4.2 All 160cc carbs will obey the fische with such components as emulsion tubes and jets
A4.2 All 200cc carbs will utilise the W50 or 922 emulsion tube and may only be use a 75 jet at all times.
A5 Exhaust
A5.1 All 3 different configurations of the GX160/200 exhausts are permitted. These are identified as the original black square box exhaust as sold when standard, the oval exhaust and the circular exhaust as sold by RPM.
A5.2 The oval and circular style exhausts must run the heat shield they are supplied with as standard as a safety feature provided the brackets on the exhaust are present, these cant be removed if sold as standard.
A6 Chassis
A6.1 Permitted Chassis
1) Any chassis UK or CIK homologated chassis up to and including the 2018 period provided they meet the criteria listed below, however, it is advisable to seek chassis acceptance prior to attempting to race with it.
a) 2, 3 or 4 Bearing
b) Adjustable rear ride height is permitted
A6.2 A maximum of 2 seat stays is permitted. These can be fitted in any configuration.
A6.3 Axles up to a maximum diameter of 50mm are permitted. Hollow or solid axles are permitted
A6.4 Extended rear hubs are permitted, hubs may overhang the rear axle.
A6.6 Akerman or single fixing point columns can be used.
A7 Chainguards/Fingerguards
A7.1 Fully enclosed chain guard must be fitted to enclose front engine sprocket and rear sprocket.
This can be modified to fit provided the chain remains enclosed. No chain must be visible when looking from above the chainguard, or if you look across from the none engine side of the axle along the axle line.
A8 Brakes
A8.1 Brakes can be hydraulic, or cable operated
A8.2 Calliper and Master Cylinder are free, except for
1) Brake disc must be steel, solid or vented, cross drilled is permitted, floating discs are also allowed.
2) No ABS
3) Maximum of 1 pad per side and 2 pistons per pad.
4) Self-adjusting systems are allowed
A8.3 Brakes must operate on the rear wheels only.
A8.4 Secondary (back-up) brake cable is required between pedal and master cylinder.
A9 Wheels and Tyres
A9.1 Aluminium or Magnesium wheels are permitted but must be of one piece moulding
A9.2 Front wheels are to be bearing or front hubs three stud types.
A9.3 Stub axles are open provided they don’t house a front braking system
A9.4 Maximum wheel width is 122mm front and 212mm rear, measured internally between the
beads. Maximum outer width is 131mm and 222mm respectively.
A9.5 Tyres are to be Maxxis Sports but a single set must be used for the whole season.
A9.5b tyres may only be replaced or changed on safety grounds after inspection and agreement.
A9.5c Treatment of tyres is not permitted, not chemicals can be added to the tyres and durometer
tests will be carried out against the base mark of the tyre.
A10 Maximum Width/Track
A10.1 Maximum front track, measured from outer most points of front tyres/wheels – 1200mm
A10.2 Maximum rear track, measured from outer most points of rear tyres/wheels – 1400mm
A11 Exotic materials
A11.1 Magnesium is allowed except for where specified within the regulations
A11.2 Carbon Fibre/Carbon composites are allowed except where specified in the regulations
A11.3 Titanium is allowed except for where specified within the regulations
A11.4 No other form of exotic material are permitted including but not limited to titanium etc
A12 Bodywork
A12.1 Chassis must run side pods and front bumper/nose cone – style Unico crash tested or newer
A12.2 Competitors must run all sponsor and Access Karting stickers supplier on either their nassua panel, side pods, engine cover or helmets or helmet.
A13 Minimum Weights
GX-UK Junior – GX160 unrestricted 120kg
GX-UK Junior – GX200 restricted 140kg
GX-UK Senior – GX160 unrestricted 126kg
GX-UK Senior – GX200 restricted 146kg
GX-UK Senior – GX200 unrestricted 162kg
A14 Number Plates/Board
A14.1 SENIOR;- Race numbers are to be black on a yellow background. Numbers to be displayed front, rear and sides.
A14.2 JUNIOR;- Race numbers are to be white on Green background. Numbers to be displayed front,
rear and sides.
A15 Rear Bumpers
A15.1 Full length rear bumper covering at least 50% of the rear tyres. The rear bumper CANNOT
protrude beyond the outer edge of the rear wheels
A15.3 JUNIOR – Full length rear bumper covering at least 50% of the rear tyres. The rear bumper
CANNOT protrude beyond the outer edge of the rear wheels
A16 Rev Counters / Data Loggers
A16.1 Rev Counters and GPS systems are allowed such as the Mychron and Alfano
A17 Steering Wheels
A17.1 Steering wheels are open fitting type, 3 and 6 bolt are allowed
A17.2 Flat top or/and bottom permitted
A17.3 3 spoke shaped fitment area for data logger wheels are allowed
A18 Age ranges
A18.1 A junior can remain in juniors in the year they turn 16, once in the year they turn 17 they must compete as a senior
A18.2 A competitor can elect to compete as a senior at 15 provided they are 16 in that calendar year
A18.3 Once a competitor has taken part in a senior race, they cannot revert to being a junior under any circumstances.