Bitumen Classes

There are 19 different classes on the AKA rule book but at club level not all of these classes are raced. Some of the classes in racing are:

Junior Classes

Age: 7 to 10 year olds
Engine:Yamaha KT100J with 12mm restricter plate or Comer S80
Approx Power: 5.5 HP
Weight Class: 90kg
Tyres: Dunlop SL1

Age: 10 to 12 year olds
Engine: Yamaha KT100J with a 16mm restrictor plate
Aprox Power: 8.5 HP
Weight Class: 100kg
Tyres: Dunlop SL1

Junior National
Age: 12 to 16 year olds
Engine: Yamaha KT100J
Aprox Power: 11 HP
Weight Class: Light 115kg - Heavy 135kg
Tyres: Dunlop SL1

The use of the KT100J engine for these three classes allows the use of the same engine, with the addition of a restrictor plate, to be used from the age of 7 to 16. These engines use a controlled muffler and are only allowed certain modifications. Allowable modifications include Blueprinting which is the re-machining the engine to reduce friction and to allow the engine to be set up for maximum performance. Area?s such as compression, port durations etc all have certain specifications which must be met. Other classes available for Juniors are Junior Clubman and Junior Piston Port but previous racing experience is required for these two classes.

Juniors, rookies and midgets also use a different size chassis to Senior drivers. Midgets and Rookies will use a rookie chassis which is the smallest kart. Depending on the brand of the chassis they will have a wheelbase that measures between 90 and 96cm. The smaller kart is easier for younger drivers to steer and manuver. Juniors will use a junior chassis that has a wheelbase between 99 and 101cm. A rookie driver may however decide to use a junior chassis if they are tall enough or a Junior driver may use a senior chassis if they feel it suits their needs better.

Senior Classes

Engine: Yamaha KT100S
Aprox Power: 17-18 HP
Weight Class: Light-140kg Heavy-160kg Super Heavy-180kg (including kart)
Tyres: MG RED

Rotax 125 Max
Engine: Rotax 125cc Max water-cooled engine with clutch and electric start
Aprox Power: 28 HP
Weight Class: Light 160kg Heavy 180kg
Tyres: Bridgstone YJC

Leopard 125
Engine: Parilla 125cc Leopard,watercooled engine with clutch and electric start
Aprox Power: 26HP
Weight Class: Light 160kg Heavy 180kg
Tyres: MG Yellow

Engine: Leopard 125, Rotax 125 Max, PRD Fireball 125
Weight: Rotax ? 160kg, Leopard ? 165kg, Fireball ? 165kg
Tyres:Rotax?Bridgestone YJC, Leopard?MG Yellow, Fireball?Maxxis, MG Yellow,YJC

Formula 100
Engine: 100cc reed or rotary
Aprox Power: 30-35 HP
Weight: 150kg
Tyres: MG Yellow

The most popular of the senior classes is the clubman class, due to the number of competitors and the cost to compete in this class. Yamaha have been manufacturing the same engine (with some minor modifications) for over 20 years. This means that a 15 year old engine will still produce as much HP as a brand new engine. As with the KT100J Engine you are allowed to blueprint the KT100S engine and modify the engine to the specifications allowed within the rules. The other classes that are becoming more popular are the 125cc classes. These are also is a single engine make class with almost no modifications allowable on the engine. The advantages of these classes are that it has an electric starter motor so that you do not need to push start the kart.

Senior karts have a wheelbase between 102.5cm and 105cm wheelbase depending on the brand. There are different chassis available for differnt classes. Please ask for further information on this subject.