Rotax 125 Max Senior (Engine Only)

For those who need a spare engine but already have all the accessories.

The engine is supplied without carburettor, radiator, electrical system, silencer, air box, battery, charger, etc.

The Rotax 125 Senior Max EVO is the latest model in a long line since Rotax built its first go-kart engine over 40 years ago.

Rotax has always focused fully on delivering an exciting, affordable riding experience combined with excellent reliability.

Rotax is in fact the only manufacturer in the world to offer a factory warranty on their racing engines — proof of the high quality these hand-built engines from Austria can deliver.

Technology:

With the Rotax 125 Senior Max Evo you get everything you could ask for in a modern go-kart engine:

• Reliable electric start with long battery life
• Official apps that help you dial in your engine perfectly
• Engine management (ignition & exhaust port and more) is handled entirely by the engine's ECU (Electronic Control Unit), giving you a perfect result every time.
• All parts are manufactured in-house at Rotax's state-of-the-art factory in Austria
• The engines have very long service intervals — up to 50 hours of running time, significantly longer than all comparable competitors.

Engine components:

Crankcase: The crankcase is manufactured from die-cast aluminium

Molten aluminium is pressed into a mould at over 15 bar of pressure. The high pressure guarantees a strong, solid casting with a perfect result.

After casting, the crankcase is machined by computer-controlled mills with extremely high precision, after which the entire crankcase is powder-coated with a durable surface finish.

Piston and cylinder: The cylinders are also cast in aluminium before being CNC-machined for as even a result as possible.

The cylinder bore is Nicasil-treated; Nicasil is one of the hardest surface treatments available and has virtually unlimited durability.

Another major benefit of Nicasil is that you only need a 2% oil mix — good for the environment and good for your wallet.

The piston is made from forged aluminium, which after machining is coated with a Teflon surface. This increases service life and gives you the best possible performance through reduced friction.

Exhaust port: The cylinder features a variable exhaust port — put simply, the cylinder changes its behaviour according to engine speed.

At low revs the exhaust port is closed, giving you a torquey engine; as the revs increase, the exhaust port is opened by the digital engine management, giving you the best possible top-end power.

You get the best of both worlds and avoid the rather hard-to-control power band found in an engine without an exhaust port.

Cooling: All Rotax engines have a closed water-cooling system that runs without external water pumps; the high flow rate and the large aluminium radiator guarantee the correct operating temperature (50-60°C) even under hard riding.

Ignition: Ignition is digital and fully electronically controlled via the engine's computer box. With the help of a sensor at the crankshaft, you are guaranteed correct ignition every time. You also get a variable ignition curve that adapts to the engine speed, all for the best possible performance.

Clutch: The clutch, made from hardened steel, transfers engine power to the drive chain and then to the rear axle.

The clutch normally lasts for several years and is maintenance-free; your engine sprocket is mounted on the clutch drum, and by swapping this you can easily re-gear the engine in under 1 minute's work.

Carburettor & fuel: A powerful vacuum-driven fuel pump feeds fuel to a 34mm Dellorto carburettor developed specifically for the Rotax engine.

The carburettor can be adjusted by changing the jet and adjusting the throttle needle; information on which setting you should use is available via the Rotax App, which, based on your location, gives you an optimal setting based on temperature and air pressure.

The engine's air intake is mounted on the carburettor; air is fed into the carburettor through a foam filter — guaranteed clean and with the correct flow.

Thanks to the smart design of the air box, running the engine in heavy rain is no problem at all.

Specifications:

• Cylinder capacity: 125cc
• Power: 30hp at 11,500 rpm
• Torque: 21nm at 9,000 rpm
• Weight: 12kg (engine only) 23kg (complete engine package)
• Ignition: Electronic ignition Exhaust port: Electronic variable exhaust port Electrical system: 12v 7ah
• Cooling: Water-cooled