The main regulations for all motorsport in the UK is found in the Motorsport UK Yearbook, including the Kart Section U.  There are important sections for licencing, judicial and safety which apply to kart racing.  Click here for the whole 2018 book, and here for just 2018 Section U

Amendment to 2017 Yearbook, click on this – issued 20.12.16

And corresponding Guidance Sheet for the new bumper regulations

The regulations for the core classes are found in the Kart Race Yearbook. Click here for a copy of the 2018 Kart Race Yearbook (known as the Gold Book)

Amendments to the 2018 MSA Kart Race Yearbook:

Amendment 1 re KZ UK and KZ2 tyres – partly superseded by Amendment 4

Amendment 2 re Honda Tech Regs V13A

Also note this clarification issued 4.5.18 for the Honda Tech Regs V13:
The following clarification is to be read in conjunction with paragraph 9 of the current Honda GX160 Technical Regulations v13a, and will be incorporated into the next update of these regulations: 

“No spark plug electrode gap is specified in the regulations, and therefore the gap measurement is free. However, under the definition of “the standard, unmodified component” the electrode should still conform in shape and relative position to an original, boxed item by way of comparison.”

Amendment 3 to permit Shell M in IAME Cadet & X30

Clarification for TKM Classes on front fairing mounting

Amendment 4 for KZ UK tyres, supersedes Amendment 1

Amendment 5 for Rotax Tyres

Amendment to Red Flag regulations August 2018

Clarification on Honda GX160 clutches issued 13.8.18

Amendment 6 regarding Rotax rain tyres barcodes


The KG Cadet rear plastic bumper is now approved for use, see here.

Smaller or new classes, or variations to the major classes, will have their own set of regulations, usually by way of a KTE (Kart Technical Exemption).

Here are some of the popular 2018 KTE’s

X30 Mini 

Junior Gearbox

210 National 

450 4-stroke Gearbox

Gillard Junior Tyro (2018 awaited)

Clubs can also offer the Clubman classes (which are lower powered and do not need the driver to take the ARKS Test so  Clubman licence is required and can be taken out on the day of the race if necessary) or Libre classes (which do need the ARKS Test).  Between them they cater for engines which are no longer homologated with their own class structure, or clubs wishing to combine a class with several compatible engines or use an engine that may not be in the regular homologated class approvals. Motorsport UK / Karting UK is open to new approvals for Clubman or Libre.

Formula Clubman, and approved variations for Honda Senior, World Formula and Junior Clubman with one Honda engine.

Formula Libre, and the approved variation for

Junior Libre with two Honda engines

All of the above regulations can be found on the Karting UK Website

2018 Honda Technical Regulations V13A (MSA approved 18.12.17), this supersedes V13 and comes into force on 31.3.2018

2017 Honda Technical Regulations V12 (MSA approved 21.12.16)

2016 Honda Technical Regulations V11a (MSA approved 23.5.16 for immediate implementation for the clarifications listed) and this version is needed for those with T1 engines.

Amendments to the 2017 Kart Race Yearbook (now out of date):

Amendment 1 – OK/OKJ ages, but see Amendment 3

Amendment 2 – KZ2 Tyre choice

Amendment 3 – OK/OKJ Ages, supersedes Amendment 1

Amendment 4 – Cadet Front Fairing/Bumper (Amended 4 January 2017)

Amendment 5 – Rotax Junior Max tyres, and Rotax EVO spark plugs

Amendment 6 – use of revoked KZ UK air boxes allowed

Amendment 7 – permission to use Shell M in X30 & IAME Cadet classes

Amendment 8 – variation of tyre marking in 250 National

International Regulations and lists of homologated equipment, including racewear, can be found on the CIK Website

Homologations are a method of certifying certain equipment, and are usually valid for a certain number of years, with regular dates (often every three years) for new applications.  This method means that the sport has stability as equipment cannot be updated at a whim by the suppliers.  The fiche is the technical document describing the equipment in often great detail.  Competitors should have copies of the homologations and fiche for the equipment they are using.

Club regulations (supplementary regulations or championships regulations) must be approved by the MSA and must reference which classes are being offered and where the regulations for these classes can be found.  Clubs usually put their local regulations on their website, see club listing.  The championship regulations will also show how points and penalties are calculated.


Summary of Main Kart Classes for 2018


Number Plate/No. Weight kg (with driver)


Ages Tyres – Dry Tyres – Wet Comments
Bambino White/Black 69 6-8 Le Cont MSA04 Le Cont MSA04 Comer C50 MSA homologated 2-stroke engine
IAME Cadet Yellow/Black 103 8-13 Dunlop LS2 MSA KT3 ‘RAC’ 60cc Parilla Gazelle un-sealed engine, clutch, pull starter
Honda Cadet Yellow/Red 103 8-13 Dunlop LS2 MSA KT3 ‘RAC’ GX160 4-stroke budget engine, clutch, pull starter
Junior TKM 2S Blue/White From 123 11-16 Maxxis TKM Green F TKM As TKM with restrictor, optional clutch, optional TAG
MiniMax Yellow/Black 135 12#-15 Mojo D1 Yellow Mojo W2 CIK Restricted version of Rotax Junior Max
Junior Max Red/White 148 13-16 Mojo D2 Mojo W2 CIK Junior version of Rotax Senior Max
MiniX White/Black 136 12#-15 Komet K1H Komet K1W Restricted version of X30 Junior
X30 Junior Green/White 148 13-16 Komet K1H Komet K1W Junior version of X30 with restrictor
OK Junior Yellow/Black 142 12-16 Vega XH CIK Vega W5 CIK Junior version of OK, these are push start karts
TKM 2S Extreme Red/White From 132 16# Maxxis TKM Green F TKM 115cc BT82, optional clutch, optional TAG
Rotax Max Blue/White 162 16# Mojo D2 Mojo W2 CIK 125cc d/drive commercial TAG class (electric start)
Rotax Max/177 Green/White 177 16# Mojo D2 Mojo W2 CIK Heavy-w’t version with 80kg min driver weight
X30 Senior Yellow/Black 164 16# Komet K1H Komet K1W Commercial TAG 125cc IAME engine, not sealed
OK Senior Yellow/Black 152 16 Vega XM CIK /TBA Vega W5 CIK / TBA International & British Championship (Vortex engine)
Formula Libre & Clubman Various   16# Various Various Catering for economy or minority classes such as Honda Junior and Senior, World Formula and older engines
Yellow/Black 175 16 Le Cont LP
Le Cont LW CIK
International & British Championship 125cc gearbox class
KZ UK Green/White 180 16 Le Cont LP Le Cont LW CIK 125cc reed valve 6 gears with 30mm carburettor
250 National White/Black 195/200* 16+ Dunlop, Le Cont , Vega all CIKOption Same makes as Dry Motocross 250cc single cylinder engines, 450 4-stroke and 175 IAME 2-stroke options, 125 Open may race in this class



Key: + means 17 years minimum for long circuit racing. 2S: 2-stroke engine; 4S: 4-stroke engine (Classes are 2S unless otherwise shown)

# means year of the birthday.  OK Junior driver must hold a National A licence.

Many class regulations call for specific tyre markings on the tyres e.g. ABKC, JAG, MSA, GB etc, See Kart Race Yearbook.

Junior classes have a minimum driver weight, for safety reasons. Junior TKM 38kg & MiniMax 39, Junior Max, 42.5, and seniors for under 16’s.

Junior Max & Junior X30 may race in year of 13th birthday for experienced drivers

*250/210 Gearbox has two weights, one when short circuit or no bodywork is fitted, the heavier for when wings or long circuit bodywork is fitted.