Kart Classes Explained
Karting really does have classes for almost every age, size and ability from age 8 upwards, but sometimes the sheer number of options can be somewhat confusing. This pictorial display should help to explain. There are basically four different categories - Cadets, Juniors, Seniors and Gearbox for karts with gears. The non-gearbox ‘direct-drive’ karts only need to have a brake on the rear axle (although some top classes have a front brake too) whereas gearbox karts must have brakes operating on all four wheels. Most of the modern direct-drive karts have a centrifugal clutch so the engine can tick-over.

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Bambino Age 6 - 8

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 the MSA, and the driver must be signed off as competent by an ARKS Instructor or Examiner before taking part in an MSA event.  Only time trials are permitted, the karts leave at set intervals on specially approved mini circuits, and are timed.  Their is a MSA Bambino Championship promoted by Zip Kart, see http://msabambino.com/   The only engine allowed is the Comer C50 with a logbook from Zip Kart, and the only tyres are Le Cont all-weather.

Cadets Age 8 - 13

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 Championship for the IAME Cadet class, and the National Championship for the Comer Class, and the ABkC National Championships for Honda Cadet, Rotax and 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 no longer has to be 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. Most but not all clubs will accept these karts and it has a national ABkC championship in the Super One.

Super Cadet
For ages from 11th year to 14th year, this class is hardly ever raced at the moment.

Juniors Age from 11/12/13 depending on class up to 17

There is no doubt that the 125cc water-cooled Rotax Max TAG (Touch and Go - electric start) categories have taken over as the most popular classes in the UK from the more traditional 100cc air-cooled two-stroke that is Formula TKM. Drivers can start racing in Rotax MiniMax or Junior TKM at age 11, then move into the more powerful Junior Max or Junior Extreme at age 13. Being a TAG class, the Rotax have a press button start whereas the TKM have to be either lifted and pushed, or use an optional plug in portable electric start box. But from 2009, TKM also offer a TAG option.  Rotax 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. The new from 2014 X30 classes are also beoming very popular at some clubs. 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.

Rotax MiniMax
MiniMax (11-15 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.

Junior Max
By taking the restrictor out of a MiniMax it is converted to a Junior Max (age 13-17 yrs). It is one of the most powerful junior classes, with top speed about 70 mph.

Junior TKM
Junior TKM (11-17 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.

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- 17 yrs with a senior equivalent.

Junior
X30
A new class for 2014, using a TAG unsealed engine and offering similar performance to Junior Max.

Formula KFJ (KF Junior formerly KF3)
The premier British championship class for 13-17 yrs (12 for experienced drivers). Also raced at European level not a class for theinexperienced.  This is not currently raced in the UK but may start in the Super One with the new OK engines from 2016.

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
https://www.msauk.org/Resource-Centre/Technical-Kart

Seniors Age 16 upwards

The junior classes all have more powerful senior equivalents. The most popular senior class in the country is Rotax Max, but there are 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. There are other TAG engines as well as Rotax, and TKM has a senior 4-stroke class. Once some experience has been gained there are further options for the premier international classes, raced primarily at the major championships. These KF class use a variety of 125cc TAG engines, similar to Max. KF 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 KF being the MSA British Championship. Senior classes top out at 85mph.

TKM Extreme
TKM Extreme is for 16 yrs upwards (although as in all the classes juniors already racing may move into the senior classes in the year of their 16th birthday). The engine is a115cc variant of the BT82. As with the juniors the chassis have to be registered, and new designs are only permitted every three years, to keep costs down. 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 KF2, 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.

X30
X30 Junior and Senior are only permitted to have club championships until 2017.  There is a 'Tour' for X30 in the Little Breen Man series and qualifying rounds for the international final in the Super One Series.

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

Gearbox Age 16 upwards (Junior 13 - 17)

Other than the Junior 85cc category for 13-17 year olds, 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 1300 metres in length.

KZ UK
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 4 seconds, top speed is 90mph on short circuit, 110 - 120mph on long circuit. The ABkC championship is promoted by the NKF and there are now support races for the class in the Super One Series. KZ1 is virtually the same but with more rigid regulations to CIK standard, and is the MSA British Kart Championship class in the Super One.

Junior Gearbox
This class uses an 85cc Honda or TM engine with 6 gears and is for 13-17 yrs.
With its four wheel braking it offers the youngsters an experience close to a single seater race-car. It’s not raced much at all now though. Currently not being run at any club.

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 on 01527 871075.