MRM NTX99 NB300 pit bike – orange

MiniRocket NTX99 NB300 – a high-performance motocross bike with a ZONSEN NB300 engine and 26 metric horsepower

MiniRocket NTX99 NB300 is a full-size off-road motorcycle built for riders who want a significantly sportier vehicle than a standard pit bike. At its heart is a liquid-cooled ZONSEN NB300 four-stroke engine with a displacement of 279.6 cm³, an output of 26 metric horsepower and a manual 6-speed gearbox. With large 21/18" wheels, hydraulic disc brakes and fully adjustable FastACE suspension, the NTX99 is ready for more demanding tracks, forest trails, training and serious off-road riding.

This model follows the philosophy of a dedicated racing range – minimal extras, maximum function. You will not find unnecessary road equipment here, but components that make sense off-road: a durable frame, a powerful engine, quality suspension, CNC aluminium parts, handguards, an hour meter, USB sockets and guards for important parts of the bike.

Who is the MiniRocket NTX99 NB300 for?

The MiniRocket NTX99 NB300 is a large motocross bike for teenage and adult riders, approximately 180 cm tall and above. With a seat height of around 950 mm and 21/18" wheels, it has the feel of a full-size vehicle, offering much more room, stability and confidence than smaller pit bike models.

The motorcycle is intended for riding away from public roads – on private land, tracks and in off-road environments. It is not intended for use on public roads.

ZONSEN NB300 engine – a powerful liquid-cooled four-stroke

At the heart of the bike is a single-cylinder ZONSEN NB300 four-stroke engine with a displacement of 279.6 cm³. The engine features a four-valve cylinder head and a balancer shaft, which helps it run more smoothly and reduces vibration. Its 26 metric horsepower output gives the bike plenty of power for spirited off-road riding, climbs, straights and technical sections.

A major advantage is liquid cooling, which helps the engine maintain a more stable operating temperature even on longer, more demanding rides. The fuel mixture is supplied by a quality NIBBI Racing PWK34 Black carburettor, popular among off-road riders for its quick throttle response and good tuning options.

Manual 6-speed gearbox

The MiniRocket NTX99 NB300 is equipped with a manual 6-speed gearbox, allowing precise control of power delivery to suit the terrain. Lower gears are useful in technical sections and on climbs, while higher gears suit faster riding on more open tracks. Power is transmitted to the rear wheel by chain drive.

Adjustable FastACE suspension

The suspension is one of this model's main strengths. At the front are USD FastACE upside-down forks. At the rear is a centrally mounted FastACE shock absorber. Both front and rear suspension characteristics are adjustable, allowing you to tailor the bike more closely to your riding style, rider weight and terrain.

The quality FastACE suspension helps the bike cope better with bumps, landings, rough tracks and faster off-road riding. Its adjustability lets you fine-tune the bike to suit a preference for greater comfort or a firmer, sportier set-up for more aggressive riding.

21/18" wheels and durable off-road tyres

The bike uses the classic full-size off-road wheel combination of 21" at the front and 18" at the rear. This combination improves its ability to tackle terrain, hold a line and ride over uneven ground. The aluminium rims are reinforced and fitted with features that improve reliability when riding at low tyre pressures and on demanding surfaces.

The knobbly tyres are designed for riding on dirt, gravel, mud and unpaved tracks. The front wheel helps maintain a precise line, while the rear tyre transfers the engine's power to the ground.

Hydraulic disc brakes

Braking is handled by hydraulic disc brakes at the front and rear. The hydraulic system offers better modulation and more assured braking performance than conventional mechanical brakes. The bike is equipped with modern brake discs inspired by those used on sporting off-road motorcycles.

A practical detail is the folding brake and clutch levers, which can pivot in several directions in a fall. This reduces the risk of them snapping if the bike is dropped or makes contact with an obstacle.

Durable frame and protective components

The bike is built around a strong steel frame designed for a load of around 130 kg. The frame has plastic guards in areas exposed to boot wear or contact with the terrain. A sump guard helps protect the underside of the bike when riding over rocks, roots and other obstacles.

There is also a front brake disc guard, an aluminium rear disc guard, a front sprocket cover and a practical recovery strap for pulling the bike out of difficult terrain.

Boost Parts CNC aluminium components

The NTX99 NB300 uses a range of aluminium and CNC-machined components. These parts help reduce weight, improve durability and give the bike a distinctly sporty look. Key components include aluminium handlebars, aluminium fork yokes, CNC footpegs, an aluminium side stand, an aluminium rear swingarm, an aluminium folding gear lever and other details.

The CNC footpegs have a sharp, grippy profile to keep your boots firmly in place, even in mud or during more aggressive riding while standing up.

Ergonomics and equipment

The long seat allows you to shift your body weight effectively when cornering, climbing and braking. The rider can easily move forwards or backwards as the situation demands. Handguards protect your hands from branches, flying stones and minor falls.

The equipment includes an hour meter, which is very useful for keeping track of service intervals. The bike also has USB sockets: 1x USB-A and 1x USB-C, which can be used, for example, to charge a camera, phone or navigation device during an off-road trip.

Key benefits of the MiniRocket NTX99 NB300

• Liquid-cooled ZONSEN NB300 engine with a displacement of 279.6 cm³
• 26 metric horsepower output
• Four-stroke single-cylinder engine with a four-valve cylinder head
• Balancer shaft for smoother engine running
• Electric starter
• Manual 6-speed gearbox
• NIBBI Racing PWK34 Black carburettor
• Adjustable FastACE suspension front and rear
• FastACE USD front forks
• Hydraulic disc brakes front and rear
• 21/18" wheels with off-road tyres
• Durable steel frame with a load capacity of around 130 kg
• Aluminium rear swingarm
• Aluminium rims and other lightweight components
• CNC aluminium footpegs, gear lever, fork yokes and other parts
• Folding clutch and front brake levers
• Sump guard
• Brake disc and front sprocket protection
• Handguards
• Hour meter
• USB-A and USB-C sockets
• Sports exhaust with a stainless steel silencer
• Gold O-Ring chain
• Recovery strap for pulling the bike out of difficult terrain

Technical specifications

Equipment and components

• Coolant radiator
• NIBBI PWK34 Black CNC carburettor
• Adjustable FastACE front suspension
• Adjustable FastACE rear suspension
• USB sockets: 1x USB-A and 1x USB-C
• Exhaust system with a stainless steel silencer
• Plastic engine guard
• Motorcycle recovery strap
• Front brake disc guard
• Gold O-Ring chain
• Sump guard
• Rear shock linkage
• Engine balancer shaft
• Aluminium handlebars
• Aluminium rims
• CNC aluminium footpegs
• CNC aluminium fork yokes
• CNC aluminium side stand
• Aluminium rear brake disc guard
• Aluminium rear swingarm
• CNC aluminium folding gear lever
• Aluminium front sprocket guard
• Aluminium oil dipstick and oil filler cap
• Aluminium chain adjusters
• Folding clutch and front brake levers
• Aluminium spoke nipples
• Aluminium tyre valve
• Rim lock to prevent inner tube slippage

Summary

MiniRocket NTX99 NB300 is a motorcycle for riders who want a powerful, well-equipped motocross bike with full-size geometry, large wheels and higher-quality components. It offers a powerful liquid-cooled ZONSEN NB300 engine, a 6-speed manual gearbox, adjustable FastACE suspension, hydraulic brakes, 21/18" wheels and an extensive equipment package including CNC aluminium parts.

If you are looking for a vehicle for genuine off-road riding that is more than just a children's or hobby toy, the MiniRocket NTX99 NB300 is exactly the kind of bike that offers the power, stability and equipment for serious riding in the dirt.