Rotax 125 DD2 MAX EVO Operator's Manual
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Rotax 125 DD2 MAX EVO Operator's Manual

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OPERATOR'S
MANUAL
125 DD2 MAX EVO
KART ED. 03/2021
PART NO. 297732
ROTAX-KART.COM

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Summary of Contents for Rotax 125 DD2 MAX EVO

  • Page 1 OPERATOR‘S MANUAL 125 DD2 MAX EVO KART ED. 03/2021 PART NO. 297732 ROTAX-KART.COM...
  • Page 2 GENERAL INFORMATION BRP-ROTAX RECOMMENDS PRODUCTS OF THE FOLLOWING COMPANIES: BRP-Rotax GmbH & Co KG T: + 43 7246 601 - 0 Follow us: Rotaxstraße 1 F: + 43 7246 6370 4623 Gunskirchen, Austria www.rotax-kart.com...

  • Page 3: Table Of Contents

    BRP-Rotax Operators Manual Table of Content Chapter INTRO – GENERAL INFORMATION Chapter 1 – Technical Description Chapter 2 – Operating fluids and battery Chapter 3 – Engine calibration Chapter 4 – Engine operation Chapter 5 – Preservation and transport Effectivity: 125 MAX DD2 evo...
  • Page 4 BRP-Rotax Operators Manual NOTES Page 2 Effectivity: 125 MAX DD2 evo Edition: March 01 2021...

  • Page 5: Chapter: Intro General Information

    BRP-Rotax GmbH & Co KG. BRP-Rotax GmbH & Co KG reserves the right at any time to discontinue or change specifications, prices, designs, features, models or equipment without incurring obligation.
  • Page 6 BRP-Rotax Operators Manual This information gives you additional advice and tips m WARNING This vehicle may exceed the performance of other vehicles you may have ridden. Take time to familiarize yourself with your new vehicle. ______________________________________________________ INTRO Effectivity: 125 MAX DD2 evo...

  • Page 7: Technical Description

    BRP-Rotax Operators Manual Chapter: 1 TECHNICAL DESCRIPTION TOPICS IN THIS CHAPTER Design of the ROTAX engine 125 MAX DD2 evo..................2 General ..............................2 Cooling circuit ............................2 Balance gear............................3 Ignition unit ............................3 Electric starter ............................3 Electro pneumatically exhaust timing control ...................3 Intake silencer............................3 Exhaust system.............................4...

  • Page 8: Design Of The Rotax Engine 125 Max Dd2 Evo

    DESIGN OF THE ROTAX ENGINE 125 MAX DD2 EVO Figure 1.1 GENERAL The Rotax 125 MAX DD2 evo engine is a single cylinder two stroke engine with reed valve controlled inlet and 125 cm displacement. Mixture lubrication is achieved by adding oil to the gasoline in a specified mixing ratio.

  • Page 9: Balance Gear

    The engine type 125 MAX DD2 evo is equipped with an electro-pneumatic exhaust con- trol. The E-RAVE (Electronic ROTAX Adjustable Variable Exhaust) system is controlled by an electro-pneumatic valve via the ECU. The vacuum required is provided by the engine crankcase.

  • Page 10: Exhaust System

    BRP-Rotax Operators Manual ________________________________________________________________ EXHAUST SYSTEM The exhaust system is designed as resonance system with an after-muffler and repre- sents a tuned system with engine. ________________________________________________________________ GEARBOX The power transmission to the rear axle takes place via manually shiftable integrated 2- speed gearbox and not as usual, via a maintenance intensive chain drive.

  • Page 11: Centrifugal Clutch

    BRP-Rotax Operators Manual CENTRIFUGAL CLUTCH The engine is equipped with a centrifugal clutch operating in an oil bath. This clutch sepa- rates the engine from the gearbox at less than 2.500 rpm. Only at an engine speed of ap- prox. 4.000 rpm. the centrifugal clutch is completely engaged.
  • Page 12 BRP-Rotax Operators Manual NOTES Page 6 Effectivity: 125 MAX DD2 evo Edition: March 01 2021...

  • Page 13: Operating Fluids And Battery

    BRP-Rotax Operators Manual Chapter: 2 OPERATING FLUIDS AND BATTERY TOPICS IN THIS CHAPTER Coolant..............................2 Battery..............................3 Battery charging unit..........................4 Fuel .................................6 See also table “important information (summary)” in Chapter 5. Effectivity: 125 MAX DD2 evo Page 1 Edition: March 01 2021...

  • Page 14: Coolant

    BRP-Rotax Operators Manual COOLANT Use only distilled water as engine coolant. If the kart is stored below the freezing tempera- ture of water, make sure to drain the water from the cooling radiator and engine completely. Step Procedure Open radiator cap and fill the system with coolant.

  • Page 15: Battery

    NOTE To charge a battery, the delivered battery charging unit specified by ROTAX® should be utilized (battery charger part no. 265148). When using the lithium bat- tery available as spare part, the battery charger Optimate Lithium (part no.

  • Page 16: Battery Charging Unit

    BRP-Rotax Operators Manual BATTERY CHARGING UNIT When charging the battery take note of the following: Step Procedure Connect battery charger to the charging connector (pos. 1). Figure 2.1: Pos. 1: Charging connector, TYPICAL Step Procedure Connect the battery charging unit on 110-230V, 50 - 60Hz power supply.
  • Page 17 When the battery is charged while not mounted on the kart, use the connector ca- ble (part no. 266022). If needed, contact your authorized distributor or one of their ROTAX® Service Centers. The charging condition of the battery can be estimated by using a commercially available measuring instrument.

  • Page 18: Fuel

    BRP-Rotax Operators Manual FUEL For engine operation, a mixture of unleaded gasoline of at least ROZ 95 / 91 (RON min. +MON) / 2 and fully synthetic two-stroke oil, mixed at ratio 1: 50 (2% oil) has to be used.
  • Page 19 BRP-Rotax Operators Manual ATTENTION Possible engine blow-up! Insufficient amount of oil in the fuel mixture (less than 2%) could result in e.g. piston seizure. ATTENTION Engine damage and damage to the intake system may occur. Do not try any different sorts of fuel.
  • Page 20 BRP-Rotax Operators Manual NOTES Page 8 Effectivity: 125 MAX DD2 evo Edition: March 01 2021...

  • Page 21: Engine Calibration

    BRP-Rotax Operators Manual Chapter: 3 ENGINE CALIBRATION TOPICS IN THIS CHAPTER ENGINE CALIBRATION..........................2 Run-in procedure ..........................2 Performance graphs ..........................2 Carburetor calibration ..........................4 Automatic-set-up ...........................5 Manual set-up ............................8 Change of the carburetor main jet ......................12 Choose of gear ratio ..........................15 Exchange of gear reduction ratio ......................17 Operation of the gear box........................19...

  • Page 22: Engine Calibration

    The vertical Y-axis shows the power in kilowatts (kW). The horizontal X-axis shows the ro- tational speed in revolutions per minute (rpm). For more information, please check the performance data sheets on www.rotax-kart.com. Effectivity: 125 MAX DD2 evo Page 2...
  • Page 23 BRP-Rotax Operators Manual Figure 3.1: Performance graphs ______________________________________________________ Effectivity: 125 MAX DD2 evo Page 3 Edition: March 01 2021...

  • Page 24: Carburetor Calibration

    The following application for smartphones shows the individual setting of your ROTAX® 125 Max DD2 evo engine: The ROTAX® Max Jetting Guide is an App for Android™ and iOS devices, designed to as- sist users with setting up the recommended main jet based on the ambient conditions and the type of engine.

  • Page 25: Automatic-Set-Up

    BRP-Rotax Operators Manual AUTOMATIC-SET-UP Step Procedure Click on the blue font "Update GPS weather data" button below the weather information. After a short time the app will automatically provide all the nec- essary information regarding weather and geographical position. Figure 3.2...
  • Page 26 BRP-Rotax Operators Manual Figure 3.3 Step Procedure Having completed all fields of the weather data and having selected the en- gine type you can press the white "CALCULATE" button on the bottom of your screen to find out the suitable jet for your engine type and environment.
  • Page 27 BRP-Rotax Operators Manual Figure 3.4 Step Procedure Now the recommended main jet value will be provided. In case a second calculation needs to be made, you can start over by simply pressing the button saying “RESET” next to the calculated value.

  • Page 28: Manual Set-Up

    BRP-Rotax Operators Manual Figure 3.5 ______________________________________________________ MANUAL SET-UP Step Procedure In case no GPS signal or internet connection is available, the necessary da- ta needs to be added manually, which of course requires knowledge about current weather conditions at the race track as well as the altitude. By click- ing on the empty space next to “Temperature”, “Altitude”, “Atmos.
  • Page 29 BRP-Rotax Operators Manual After all the necessary information has been provided and selected, you on- ly need to click the circular red button saying “CALCULATE” at the bottom of the screen. Now the recommended main jet value will be provided. In case a second calculation needs to be made, you can start over by simply pressing the button saying “RESET”...
  • Page 30 BRP-Rotax Operators Manual Figure 3.7 Please scan the following QR-code for a detailed instruction video: Figure 3.8: QR- code App Download Please scan the following QR-code for your mobile device: Effectivity: 125 MAX DD2 evo Page 10 Edition: March 01 2021...
  • Page 31 BRP-Rotax Operators Manual Figure 3.9: QR- code, Android device Figure 3.10: QR- code, iOS device For better understanding and as help for carburetor adjustment, the following figure de- scribes the effect of the various adjustments, depending on the throttle position.

  • Page 32: Change Of The Carburetor Main Jet

    BRP-Rotax Operators Manual CHANGE OF THE CARBURETOR MAIN JET To change the carburetor main jet, proceed as follows: Tools required: • Open-end wrench 19 mm • Flathead screwdriver NOTE The carburetor must not be removed from the engine in order to change the jetting.
  • Page 33 Operators Manual Step Procedure Select the appropriate size of main jet, refer to ROTAX® Max Jetting Guide. Install the main jet cup (pos. 14) in position and fit the corresponding main jet (see ROTAX® Max Jetting Guide). Fit and hand-tighten the plug screw (pos. 27) and gasket ring (pos. 26).
  • Page 34 BRP-Rotax Operators Manual NOTE In a disassembled carburetor, the position of the jet needle (pos. 3) can be changed. The standard position of the jet needle is ‘position 2’. If the clip (pos. 4) is set in ‘position 1’ of the jet needle, the full mixture in part and full-load will be- come slightly leaner.

  • Page 35: Choose Of Gear Ratio

    BRP-Rotax Operators Manual CHOOSE OF GEAR RATIO In spite of its 2 gears, the 125 MAX DD2 evo engine offers a broad performance band. Therefore, the frequent changing of the primary gear ratio is not necessary. NOTE It is not possible to change the 1 and 2 gear individually.
  • Page 36 BRP-Rotax Operators Manual If these gear ratios are still not sufficient, try the next shorter or next longer gear ratio. NOTE When using short gear ratios, it may happen that the response behavior of the en- gine in 1 gear is aggressive and the vehicle handling becomes difficult. For a good lap time, often a longer gear ratio is helpful to achieve reasonable perform- ance behavior.

  • Page 37: Exchange Of Gear Reduction Ratio

    BRP-Rotax Operators Manual Gear ratio 2 gear Number Number of Gear ratio Traditional Theoretical max. speed of teeth of teeth of gear ratio (in km/h / mile/h) (at primary (in sprocket 12.500 rpm and wheel secondary drive gear size) diameter 870 mm /34.25 drive gear in.)
  • Page 38 BRP-Rotax Operators Manual Figure 3.13: Gear cover Step Procedure Remove the primary drive gear (pos. 4) and secondary gear (pos. 5) and fit the gear pair of your choice. NOTE At re-assembly, proceed in reverse sequence. Tighten the screws to the following torque settings: M6: 10 Nm (88 lbf.

  • Page 39: Operation Of The Gear Box

    Operators Manual OPERATION OF THE GEAR BOX The ROTAX® 125 MAX DD2 evo is fitted with a 2-speed gearbox that is changed man- ually via a shifting device. The engine also has an electronic ignition cut-off which when changing from 1...

  • Page 40: Adjustment Of Gear Shifting

    BRP-Rotax Operators Manual ADJUSTMENT OF GEAR SHIFTING The perfect functioning of gear shifting depends to a great extent on the correct adjust- ment of the gear shifting mechanism. NOTE When the engine is not running, it may not be possible to engage gears, depend- ing on the position between shifting sleeve and idle gear of the first or second gear.
  • Page 41 BRP-Rotax Operators Manual Figure 3.15: Adjusted Effectivity: 125 MAX DD2 evo Page 21 Edition: March 01 2021...
  • Page 42 BRP-Rotax Operators Manual NOTES Page 22 Effectivity: 125 MAX DD2 evo Edition: March 01 2021...
  • Page 43 BRP-Rotax Operators Manual Chapter: 4 ENGINE OPERATION TOPICS IN THIS CHAPTER ENGINE OPERATING ..........................2 Engine start ............................2 Stopping the engine..........................4 Setting of the exhaust valve timing ......................5 Maintenance schedule for engine components ..................8 Operating Limits ..........................10 Effectivity: 125 MAX DD2 evo...

  • Page 44: Engine Operating

    BRP-Rotax Operators Manual ENGINE OPERATING ENGINE START Before starting the engine, make sure you have completed all necessary tasks for running the engine: Fuel tank full. ✔ ✔ Battery charged and connected. ✔ ✔ Battery voltage over 12 V. ✔ ✔...
  • Page 45 BRP-Rotax Operators Manual Figure 4.2: Power button Procedure Step After engine start, take choke back until engine idles smoothly without choke. m WARNING Non-compliance can result in serious injuries or death! Always wear protective clothing for kart operation (helmet, overall, gloves, shoes, neck and rib guards).

  • Page 46: Stopping The Engine

    BRP-Rotax Operators Manual ATTENTION Non-compliance can result in engine damage! Keep to running-in procedure as directed. ATTENTION Operate engine only within the specified limits and intended purpose. m WARNING Non-compliance can result in serious injuries or death! Only get in and out of the kart if engine is not running.

  • Page 47: Setting Of The Exhaust Valve Timing

    BRP-Rotax Operators Manual SETTING OF THE EXHAUST VALVE TIMING Tools required: • Allen key 4 mm or Socket wrench 8 mm The opening time of the exhaust valve is set in the ECU and depends on the engine speed. However, the ECU allows two different modes of the exhaust valve opening. These can be selected by connecting an additional cable to the cylinder head cover.
  • Page 48 BRP-Rotax Operators Manual Figure 4.4: Ground wire Variant 2: Additional cable on starter relay Cable on starter relay. The additional cable is NOT attached to the ground wire. The control of the exhaust valve timing is activated at 9100 rpm.
  • Page 49 BRP-Rotax Operators Manual Figure 4.5: Cable on starter relay NOTE Either variant 1 or variant 2 has been installed in your engine. ______________________________________________________ Effectivity: 125 MAX DD2 evo Page 7 Edition: March 01 2021...

  • Page 50: Engine Operation

    Tear-down inspection of Inspect following com- engine (must be con- ponents and replace if ducted by an authorized requested: piston, pis- ROTAX® Service ton pin and piston pin Center) bearing, conrod and conrod bearing, main bearings of crankshaft. Clean airfilter, apply oil,...
  • Page 51 BRP-Rotax Operators Manual FREQUENCY NOTES ENGINE Before After Every Every Every Every every every opera- opera- hours hours hours hours tion tion of op- of op- of op- of op- era- era- eration era- tion tion tion Renew damping material...

  • Page 52: Operating Limits

    BRP-Rotax Operators Manual OPERATING LIMITS Operating the engine is only permitted under following conditions: Recommended coolant temperature rang: 45 °C – 85 °C (113 °F – 185 °F). ATTENTION Operating the engine at a too low temperature could result in piston seizure.

  • Page 53: Preservation And Transport

    BRP-Rotax Operators Manual Chapter: 5 PRESERVATION AND TRANSPORT TOPICS IN THIS CHAPTER Preservation and transport........................2 Preservation of engine and equipment ....................2 Transport of the kart..........................2 IMPORTANT INFORMATION (SUMMARY).....................3 Notes ..............................4 Effectivity: 125 MAX DD2 evo Page 1 Edition: March 01 2021...
  • Page 54 BRP-Rotax Operators Manual PRESERVATION AND TRANSPORT PRESERVATION OF ENGINE AND EQUIPMENT For longer periods out of operation (winter time), make sure that the engine will be properly preserved. Step Procedure Detach carburetor, drain fuel from carburetor and close carburetor openings to ensure that no dust or dirt can enter.
  • Page 55 BRP-Rotax Operators Manual IMPORTANT INFORMATION (SUMMARY) IMPORTANT Liter GAL. SPECIFICATION RECOMMENDED INFORMATION BRANDS FUEL Unleaded fuel of minimum octane level of 95 ROZ resp. 91 MOZ Fully synthetic 2–STROKE OIL XPS Kart-Tec OIL IN FUEL MIX- During break-in: 1:33 (=3% oil)
  • Page 56 BRP-Rotax Operators Manual NOTES ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ ________________________________________________________________________________ Effectivity: 125 MAX DD2 evo...
  • Page 57 Coolant ..............2 Cooling circuit ............2 Operating limits...........10 Operation of the gear box ........19 Overload clutch.............5 Design of the ROTAX engine 125 MAX DD2 evo ..2 Performance graphs..........2 Electric starter............3 Preservation and transport........2 Electro pneumatically exhaust timing control ...3 Preservation of engine and equipment ....2 Electronic Shifting Assistant (ESA) ......4...

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