ROTAX FR125 MAX ENGINES

The sensation in karting worldwide is the incredible watercooled Rotax FR125 Max engine. Designed for both the racing and recreational markets, the engine combines the best of both worlds. Engineered and manufactured by one the world's leading racing kart engine producers it has a true race pedigree, producing over 28 horsepower , while the unique simplicity and self-starter provides the ultimate in hassle-free karting.

It can easily be mounted to almost any kart chassis with a simple kit available, giving anyone the chance to experience the renowned power and reliability of Rotax.

The ROTAX FR125 MAX engine range is the official engine for ROTAX MAX Challenge. It is the best choice for any kart enthusiast.

ROTAX FR125 MAX

Description: ROTAX-single-cylinder | 2-stroke, reed valve engine | oil in fuel lubrication | liquid cooled with integrated water pump | digital battery ignition | pneumatic adjusted exhaust valve | balance shaft | centrifugal clutch | integrated electric starter.

Power-pack	ROTAX 125 MAX
Bore	54,0 mm
Stroke	54,5 mm
Displacemen	124,8 cm3
Capacity	21 kW at 11750 rpm
Torque	21 Nm at 8750 rpm
Max RPM	13.600 rpm (electronically rev. limiter)
Carburettor	DELL‘ORTO VHS 34 QS
Fuel Pump	Mikuni diaphragm pump
Intake Silencer	Tuned intake silencer system with integrated air filter
Exhaust system	Tuned exhaust pipe with after muffler
Lubrication	Oil in fuel, high quality 2-stroke oil, mixing ratio 2%
Weight of engine only	Approx. 12 kg (without accessories)

IMPORTANT INFORMATION

OIL/FUEL RATIO FOR ROTAX MAX FR125 ENGINES

The Rotax Max FR125 engine has revolutionised karting with its ease of use, long life between rebuilds and its incredible reliability, however like every engine, sometimes things can go wrong.  The most common failure we see is the big end and although it is still comparatively uncommon, it is arguably the weak point of the engine.
In an effort to reduce the incidence of conrod big end failures, Rotax has advised the following rin in prcedure. 

RUN-IN PROCEDURE.

To ensure the engine componenets have the longest possible life span, the engine must be sudject to a defined running-in period at first operation of engine or after a repair of the crnkshaft or displacement parts.

To warrant the best running-in conditions we recommend to fill the tank  the first time with a slightly oil-enriched fuel/oil mixture ratio of 33:1 (3% oil).  After the end of the running-in period run the engine without fail on the specified fuel/oil  mixture ratio of 50:1 (2% oil), to prevent trouble like coking of the exhaust valve.

Attention: A fully synthetic 2-stroke oil must be used.

Run in procedure 1: Start the engine and run the kart for 15 minutes on a race track changing load and engine speed up to 7500 r.p.m. 

Run in procedure 2: Once the engine has cooled down run the kart for another 15 minutes with load and speed changes up to 9500 r.p.m.

Load and speed changes mean:

Fully open the accelerator until the engine reaches the r.p.m mentioned above - lift of the accelerator completely until the r.p.m comes back down to 5000 r.p.m and accelerate again.

After this running-in period is complete the full powre of the engine may be used.

Warning

This engine must never be operated above 14000 r.p.m or without any load on the engine (i.e. on a kart trolley) as this can dramtically shorten the life span of the engine components ( conrod, bearings etc).