MRM NTX99 NB300 pit bike – yellow

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

MiniRocket NTX99 NB300 is a full-size off-road motorcycle built for riders who want a significantly sportier machine 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 hp 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 a pure racing philosophy – minimum extras, maximum functionality. 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 machine, offering much more room, stability and confidence than smaller pit bike models.

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

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

At the heart of the bike is a ZONSEN NB300 single-cylinder 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 hp output gives the bike plenty of power for brisk off-road riding, climbs, straights and technical sections.

A major advantage is liquid cooling, which helps the engine maintain a more stable operating temperature during longer, more demanding rides. The fuel mixture is supplied by a quality NIBBI Racing PWK34 Black carburettor, popular with 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 a chain drive.

Adjustable FastACE suspension

The suspension is one of this model's main strengths. At the front are FastACE USD upside-down forks. At the rear is a centrally mounted FastACE shock absorber. Both front and rear suspension characteristics can be adjusted, 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 according to whether the rider prefers a more comfortable feel 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 off-road tread is designed for riding on soil, gravel, mud and unsurfaced tracks. The front wheel helps the bike hold its line accurately, while the rear tyre transfers engine 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 sporting off-road motorcycles.

A practical detail is the folding brake and clutch levers, which can move in several directions in a fall. This reduces the risk of them breaking 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 is fitted with plastic guards in areas exposed to rubbing from boots or contact with the terrain. A skid plate beneath the engine 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 appearance. Key features 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, keeping your boots firmly in place even in mud or during more aggressive riding while standing up.

Ergonomics and equipment

The long seat makes it easy to shift your body weight when cornering, climbing and braking. The rider can move forwards or backwards easily to suit the situation. Handguards protect the hands from branches, flying stones and minor falls.

The equipment includes an hour meter, which is particularly 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 hp output
• Four-stroke single-cylinder engine with a four-valve cylinder head
• Balancer shaft for smoother engine operation
• Electric starter
• Manual 6-speed gearbox
• NIBBI Racing PWK34 Black carburettor
• Adjustable FastACE suspension at the front and rear
• FastACE USD front forks
• Hydraulic disc brakes at the 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
• Engine skid plate
• Brake disc and front sprocket guards
• 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
• Engine skid plate
• 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

The 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 machine for real off-road riding that goes beyond a children's or hobby toy, the MiniRocket NTX99 NB300 is exactly the kind of bike that delivers the power, stability and equipment for serious riding off-road.