• Bambino Age 6-8
  • Cadets Age 8-13
  • Juniors Age 11-16 (Depending On Class)
  • Seniors Age 16+
  • Gearbox Age 16+ (Junior 13-16)

Boys and girls can start in Bambinos from their 6th birthday to the end of the year they turn 8. The karts and engines must be registered with Motorsport UK, the engine being a Comer C50, and the driver must be signed off as competent by an ARKS Instructor or Examiner before taking part in an Motorsport UK time trial event. The training schedule is available here: Bambino Training Guidelines

The Record Card must be downloaded and printed off and each module signed off by an ARKS Examiner or Instructor, then when all modules are complete and the driver is assessed competent the Record Card is put in with the normal Licence Form and posted to the Motorsport UK. The PG Entrant part of the licence form must also be completed. These first licences are currently free. The forms can be used in lieu of a Bambino Clubman licence at the first event if there is insufficient time to post the licence applications.

Time trials are where the karts leave at set intervals on specially approved circuits, and are timed. There is a Motorsport UK Bambino Championship promoted by Zip Kart, see https://www.britishkartchampionships.org . The only engine allowed is the Comer C50 with a logbook from Zip Kart, and the only tyres are Le Cont all-weather. Drivers can race in the Bambino class from the age of 6 if they buy the Go Karting pack from Motorsport UK and take the full ARKS Novice Driver Test. The races will hold timed qualifying to set the grids for the heats, and only at specially approved circuits.

Boys and girls can start racing karts at the age of 8 in one of the Cadet classes, although some tracks will allow youngsters to practice from the age of 7. They can continue until the end of the year of their 13th birthday, although they may be getting too heavy by then and so can move into certain Junior classes from the age of 11. The three Cadet classes are described below and all are permitted to race together. All have a centrifugal clutch and a recoil starting cord. The special minikarts used are registered with prices controlled to an agreed maximum. Top speed is about 50mph. The Super One Series holds the British Cadet Championshipfor the IAME Cadet class and the ABkC National Championships for Honda Cadet, Rotax and MSA TKM Classes. 

IAME Cadet

Uses a 60cc unsealed 2-stroke Parilla Gazelle UK engine, new from 2013.
Because this is the class used for the premier championships, it is run by most clubs.

Honda Cadet 

Honda Cadet uses a 4-stroke Gx160 engine which is not sealed. The long life engines are very low-cost but have to conform to a technical specification which is on the www.abkc.org.uk website in the Regulations section. Most clubs will accept these karts and it has a national ABkC championship in the Super One.  Honda Cadet is the biggest class in the UK.

Class regulations for these classes are in the MSA Kart Race Yearbook and are on the ABkC (www.abkc.org.uk ) website along with any amendments.

There is no doubt that the 125cc water-cooled Rotax Max TAG (Touch and Go – electric start) categories has the most popular classes in the UK from the more traditional 100cc air-cooled two-stroke that is Formula TKM but they are now challenged by the newer X30 classes. Drivers can start racing in Rotax MiniMax or MiniX from the year of 12th birthday or Junior TKM at age 11, then move into the more powerful Junior Max or Junior X30 at age 13 (or year of 13th with prior experience). Being a TAG class, the Rotax and X30 have an electric press button start whereas the TKM can be either lifted and pushed, or use an optional plug in portable electric start box or use the TAG electric start option which is becoming very popular.  Rotax and X30 are more expensive initially but the engine runs longer between rebuilds, so the running costs can be less. The TKM’s are at the economy end for initial purchase with strict price controls. Top speeds in the junior classes vary from 55mph to 75mph. The best advice here, as in all classes, is to visit your local circuit to see what is popular in your area. Drivers in the 11 year old junior classes must weigh a minimum of 38kg with suit, helmet and boots.  At 13 it is usually 40kg for the more powerful classes but check class regulations in the MSA Kart Race Yearbook.

Rotax MiniMax

MiniMax (Year of 12th birthday-15 yrs) is the lowest powered class of the Rotax family, and uses a very restricted 125cc 2-stroke TAG engine. All Rotax engines are sealed and have a log-book showing the service history.  There is an ABkC National Championship in the Super One Series.

Junior Max

By taking the restrictor out of a MiniMax it is converted to a Junior Max (age 13-16 yrs). It is one of the most powerful junior classes, with top speed about 70 mph.  There is a ABkC National Championship in the Super One Series.

Junior TKM

Junior TKM (11-16 yrs) is a popular traditional kart class using a BT-82 piston-port engine to a strict non-tuning regime.  The junior engines have a choice of restrictors between the carburettor and the engine to limit the power, the choice depends on the driver weight.  There is an ABKC MSA National Championship in the Super One Series.

Junior TKM 4-Stroke

Tal-Ko, who make the TKM engines, also make a 200cc long-life 4-stroke. Not raced at most clubs currently. For 11- 16 yrs with a senior equivalent.


MiniX (Year of 12th birthday-15 yrs) is the lowest powered class of the X30 family, and uses a very restricted 125cc 2-stroke TAG engine. By changing the carburettor and some components it can be converted to a Junior X30.

Junior X30

A new class from 2014, using a TAG unsealed engine and offering similar performance to Junior Max.  There is a national championship in the Super One Series

Formula OKJ

The premier British championship class for 12-16 yrs (or younger for experienced drivers racing in the CIK events). Also raced at European level not a class for theinexperienced.  This is raced in the UK as the MSA Junior British Kart Championship in the Super One.  The karts do not have electric starts but are easily push started with a de-compressor valve assistance.

Junior 4-stroke classes

There are other 4-stroke classes for Junior and Seniors which run at certain clubs only e.g. Honda classes and World Formula (senior only).  More information on https://www.msauk.org/Resource-Centre/Technical-Kart

The junior classes all have more powerful senior equivalents. The most popular senior class in the country are Rotax Max, Senior TKM Extreme and Senior X30 and there may be other options worth exploring at your local circuit. The once all-conquering TKM Extreme class is now only popular in certain areas, eg in the Midlands, and if you live in such an area it should be investigated. Once some experience has been gained there are further options for the premier international classes, raced primarily at the major championships. These OK class use a variety of 125cc TAG engines, from different manufacturers. OK is unlikely to be seen at club level. They are restricted in maximum rpm for longer life. Both are raced in the Super One Series with OK Senior being the MSA British Championship. Senior classes top out at 85mph.

TKM Extreme

TKM Extreme is for year of 16th birthday upwards (although as in all the classes very experienced juniors already racing may move into the senior classes earlier). The engine is a115cc variant of the BT82.  It’s a popular and economic class and now has a TAG option.

Rotax Max

The senior equivalent of Junior Max, with a very powerful 125cc TAG engine. Although the maximum revs are limited electronically, they are nearly as quick as OK, but much lower maintenance, and sealed to prevent unapproved tuning. Care needs to be taken if starting in this class. Like many classes there is a higher weight variant called Rotax 177 for the heavier driver.


A TAG electric start water cooled 125cc engine which is not sealed so anyone can do rebuilds.  There is a ‘Tour’ for X30 in the Little Breen Man series and a National Series in the Super One.

Senior 4-stroke classes

There are other 4-stroke classes for Junior and Seniors which run at certain clubs only e.g. Honda classes and World Formula (senior only).  More information on http://www.abkc.org.uk/startkart.htm

Image Credit: Tuto Super One Series Round 1: Rowrah, March 18/19, 2017

Other than the Junior 85cc category for 13-16 year olds which is only raced at one or two clubs, gearbox karts offer the highest powers and speeds. They can have either 2 pedals – brake and accelerator – like the direct drive classes, or 3 pedals, one of which is a foot clutch, like a car. Most 125’s use karts very similar to the direct drive karts except for the four wheel brakes. They have a hand clutch mounted next to the steering wheel, which is only used to move off from a standstill. At most circuits a standing start is used, as opposed to the rolling formation start that direct drive karts have.

Gearbox karts can also be used on the long motor racing circuits, although everyone should preferably start on the short circuits which are typically 900 to 1400 metres in length.


KZ UK is the most popular gearbox class. Although a little more expensive than a direct drive class, they can be surprisingly economical to run. The 125cc water cooled engines have six gears, sequentially operated like motorcycle using a gear-lever mounted next to the steering wheel. 0-60mph times are less than 3 seconds, top speed is 90mph on short circuit, 110 – 120mph on long circuit. The ABkC championship is promoted by the NKF. KZ2 is virtually the same but with more rigid regulations to CIK standard, and is the MSA British Kart Championship class but may not be run.

Junior Gearbox

This class originally used an 85cc Honda or TM engine with 6 gears and is for 13-16 yrs, currently only running in the Channel Islands.  For 2021 it is proposed to offer the class with restricted KZ 125cc engines.
With its four wheel braking it offers the youngsters an experience close to a single seater race-car. It is hoped the new class will attract more juniors.

250 National

This is the most powerful short-circuit class using 250cc single cylinder motocross 5- speed engines. The karts are often equipped with large full width nose cones and wings, especially when used on the long circuits. Top speeds are 100mph on short circuit, 140mph on long circuit. Twin cylinder Superkarts can reach 170mph though. The NKF holds the ABkC national championship. Some clubs offer the 450cc 4-stroke engine class which may be raced in parallel with 250 National but for separate prizes.

210 National

A classic class using the Villiers 197cc engine or derivatives. Administered by the drivers themselves through the 210 Challenge group, contact is Kate Bateman email A classic class using the Villiers 197cc engine or derivatives. Administered by the drivers themselves through the 210 Challenge group, contact is Sian Masson email 210challenge@talktalk.net

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