The Rotax Max group of classes were designed by Bombardier to provide cost-effective but high speed kart racing. The engine used is a fixed-gear 125cc reed valve engine which is sealed, and only authorised "Service Centres" are allowed to carry out maintenance. Rebuilds are recommended after 50 hours compared with 2-3 for other two-stroke engines. Bombardier Inc. ... Indoor Kart racing Kart racers race each other on an outdoor track Kart racing (as the word is so spelled by enthusiasts) or karting is a variant of open-wheeler motor sport with simple, small four-wheeled vehicles called karts, go-karts, or gearbox/shifter karts depending on the design. ... Reed valves consist of thin flexible metal or fiberglass strips fixed on one end that open and close upon changing pressures across opposite sides of the valve much like heart valves do. ... The two-stroke cycle of an internal combustion engine differs from the more common four-stroke cycle by having only two strokes (linear movements of the piston) instead of four, although the same four operations (intake, compression, power, exhaust) still occur. ...

There are several different versions of the engine. The original has a power valve and produces around 28hp, and is used by racers aged 16+. The Junior engine has no power-valve and produces 20.5hp (age 13-16), and the Minimax has a restrictor plate in the carburettor which restricts it to 13hp. There is also the RM1, which has two gears and is direct drive in that the axle goes through the engine without need for a chain. The 2-stroke power valve system is referred to as such because it takes just two strokes (or cycles) to complete the four essential actions in power delivery: intake; compression; combustion; and exhaust. ... Restrictor plates are devices installed between the carburetor and intake manifold that restrict the amount of air and fuel entering the engines combustion chamber. ... The carburetor (or carburettor, carb for short) is a device which mixes air and fuel for an internal_combustion engine. ...

The concept was introduced to karting in 1998 and almost immediately began to gain market share from other slower and more expensive classes.

Rotax organises the Rotax Max Challenge for racers all over the world, who compete at a national level. The top drivers in each national series are invited to compete at the World Finals in a holiday destination such as Lanzarote with all their expenses paid. Lanzarote, a Spanish island, is the easternmost of the Canary Islands, in the Atlantic Ocean ca. ...

rotax junior can reach up to 70 mph whilst minimax can reach up to 55 mph