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BRP ROTAX 125 SENIOR MAX EVO Repair Manual
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BRP ROTAX 125 SENIOR MAX EVO Repair Manual

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REPAIR
MANUAL
125 SENIOR MAX EVO
125 JUNIOR MAX EVO
125 MINI MAX EVO
125 MICRO MAX EVO
ROTAX-KART.COM

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Summary of Contents for BRP ROTAX 125 SENIOR MAX EVO

  • Page 1 REPAIR MANUAL 125 SENIOR MAX EVO 125 JUNIOR MAX EVO 125 MINI MAX EVO 125 MICRO MAX EVO ROTAX-KART.COM...
  • Page 2 BRP-Rotax REPAIR MANUAL Chapter: INTRO GENERAL INFORMATION Preface Before carrying out repair work on the engine, read the Repair Manual carefully. If any passages of the Manual are not clearly understood or if you have questions, please contact an authorized Distribution or Service Center for ROTAX®-kart engines.
  • Page 3 BRP-Rotax REPAIR MANUAL NOTES Page 2 Effectivity: 125 MAX evo, Junior MAX November 01 2021 evo, Mini MAX evo, Micro MAX evo...

  • Page 4: Table Of Contents

    Use for intended purpose ........................5 Technical data ............................6 Purpose This Repair Manual is based on information and the state-of-knowledge of BRP-Rotax of the product current at the date of issue. Documentation For additional information on engines, maintenance or parts, you can also contact your nearest authorized ROTAX®-Engine distributor.

  • Page 5: Abbreviations And Terms Used In This Manual

    BRP-Rotax REPAIR MANUAL ABBREVIATIONS AND TERMS USED IN THIS MANUAL Abbreviations Description Abbreviations Degree Celsius (Centigrade) °C Degree Fahrenheit °F Revolutions per minute see Manual (Type designation) 125 MAX evo see Manual (Type designation) 125 Junior MAX evo see Manual (Type designation)

  • Page 6: Safety

    Always take care by conducting manual work and use safety equipment. The information and components-/system descriptions con- tained in this Manual are correct at the time of publication. BRP-Rotax, however, main- tains a policy of continuous improvement of its products without imposing upon itself any obligation to install them on its products previously manufactured.

  • Page 7: Instruction

    Non-approved modifications to the engine and associated components likewise releases BRP-Rotax from its warranty obligations. Accessories This engine must only be operated with accessories supplied, recommended and re- leased by BRP-Rotax. Modifications are only allowed after the exceptional advice or ap- proval by the engine manufacturer. Spare parts ATTENTION Spare parts must comply with the requirements defined by the engine manufacturer.

  • Page 8: Technical Documentation

    The current edition of the Manual is shown at the bottom of the pages or on the front cover. Reference Any reference to a document refers to the latest edition issued by BRP-Rotax, if not stated otherwise. Illustrations The illustrations in this Manual are sketches and show a typical arrangement. They may not represent in full detail or the exact shape of the parts which have the same or similar function.

  • Page 9: Technical Data

    BRP-Rotax REPAIR MANUAL TECHNICAL DATA 125 MAX evo / 125 Junior MAX evo / 125 Mini Engine Type MAX evo / 125 Micro MAX evo Bore/stroke 54.00 mm / 54.5 mm Displacement 125.0 ccm Nominal power (max.) 22 kW at 11500 rpm...
  • Page 10 BRP-Rotax REPAIR MANUAL 125 MAX evo / 125 Junior MAX evo / 125 Mini Engine Type MAX evo / 125 Micro MAX evo 50 ml (for plastic balance gears) / 100 ml (for steel Engine oil capacity balance gears) Engagement speed approx.
  • Page 11 BRP-Rotax REPAIR MANUAL NOTES Page 8 Effectivity: 125 MAX evo, Junior MAX November 01 2021 evo, Mini MAX evo, Micro MAX evo...
  • Page 12 BRP-Rotax REPAIR MANUAL Chapter: Chapter 2 MAINTENANCE TOPICS IN THIS CHAPTER General note ............................2 Authorized personnel ..........................3 Process advice ............................4 Consumable materials..........................6 Special tools............................8 Inspection and servicing intervals of the engine components...............10 Contents The information given in the Repair Manual is based on data and experience which are considered to be applicable for a skilled mechanic under normal working conditions.
  • Page 13 We particularly emphasize that parts and accessories not supplied as genuine BRP-Rotax accessories parts are not verified for suitability by BRP-Rotax and thus are not authorized for use. In- stallation and/or use of such products may possibly change or negatively influence the constructive characteristics of the engine.
  • Page 14 • Appropriate tools and fixtures as outlined in the ROTAX® Repair Manual. • Reasonable maintenance practices are utilized. Information Maintenance organizations and individuals are encouraged to contact BRP-Rotax through its worldwide distribution network for information and guidance on any of the tasks out- lined herein.
  • Page 15 BRP-Rotax REPAIR MANUAL PROCESS ADVICE Safety note m WARNING Non-compliance can result in serious injuries or death! When carrying out maintenance and service work, respect without fail the safety regulations. Ignition “OFF” m WARNING Non-compliance can result in serious injuries or death! This precautionary measure serves to avoid any injuries in case of an unintentional start of the engine.
  • Page 16 BRP-Rotax REPAIR MANUAL Cleaning of parts ATTENTION Use suitable agents and materials. All metal and synthetic parts are generally washed with suitable cleaning agents. Be- fore using new and unknown cleaning agents check the compatibility of materials. Removed parts Before re-using disassembled parts, clean, check and refit them as per instructions.
  • Page 17 REPAIR MANUAL CONSUMABLE MATERIALS General note ATTENTION Use only the specified or technically equivalent materials from BRP-Rotax for all maintenance work. When handling chemicals, comply with all the customary regulations and specifications of the producer, including the expiry date and instruction.
  • Page 18 BRP-Rotax REPAIR MANUAL ATTENTION Use only approved cleaning agents (e.g. kerosine, varsol, etc.) for cleaning all metal parts. Do not use lye-based cold cleaner or degreasing agents. Do not clean coolant or oil ho- ses with aggressive solutions. Clean off sealing compound residue with sealant remov- er.
  • Page 19 BRP-Rotax REPAIR MANUAL SPECIAL TOOLS Figure 2.2 Chapter 2 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo Page 8 November 01 2021...
  • Page 20 BRP-Rotax REPAIR MANUAL Part no. Description 277381 Fixation tool for crankshaft 276016 Puller assy. 676010 Insertion sleeve 676021 Insertion jig (oil seal water pump) 676030 Insertion jig (E-Starter needle bushing) 676040 Insertion tool 676035 Insertion tool (piston pin circlip) 877930...
  • Page 21 BRP-Rotax REPAIR MANUAL INSPECTION AND SERVICING INTERVALS OF THE ENGINE COMPONENTS Safety note m WARNING Non-compliance can result in serious injuries or death! All repair and maintenance work must only be carried out by a qualified technician. Points of inspection...
  • Page 22 BRP-Rotax REPAIR MANUAL Points of inspection Interval Chapter Operating Reference hours Inspection, remedial action as indicated 4) Fuel system Inspect fuel filter for dirt, replace if Inspect before required. every operation of vehicle Inspect fuel screen from the Every 10 hours carburetor.
  • Page 23 BRP-Rotax REPAIR MANUAL NOTES Page 12 Effectivity: 125 MAX evo, Junior MAX November 01 2021 evo, Mini MAX evo, Micro MAX evo...
  • Page 24 BRP-Rotax REPAIR MANUAL Chapter: Chapter 3 ENGINE TOPICS IN THIS CHAPTER System description ..........................2 Preparation for removal...........................3 Removal of the ignition system .......................3 Removal of the exhaust system ......................6 Removal of radiator with cap assy......................6 Removal of the fuel line..........................7 Removal of the Bowden cable ........................8...
  • Page 25 BRP-Rotax REPAIR MANUAL SYSTEM DESCRIPTION Overview Engine Figure 3.1: Engine components Engine Carburetor Exhaust system Intake silencer Fuel pump Radiator Battery mounting + ECU Chapter 3 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo Page 2...
  • Page 26 BRP-Rotax REPAIR MANUAL PREPARATION FOR REMOVAL Safety instructions m WARNING Danger of severe burns and scalds! Always allow the engine to cool down to ambient temperature before starting any work. REMOVAL OF THE IGNITION SYSTEM Safety instructions m WARNING Risk of electric shock! Ignition “OFF”...
  • Page 27 BRP-Rotax REPAIR MANUAL Figure 3.2: Battery Battery cover O-ring Allen screw with rounded flange head Positive battery terminal Negative battery terminal _________________________________________________ Instruction Figure: Ignition system. 4. Pull the spark plug connector (1) off the spark plug. Minimum removal force 30 N.
  • Page 28 BRP-Rotax REPAIR MANUAL Figure 3.3: Ignition system Spark plug connector Ignition coil Crankshaft positioning sensor (CPS) Electric starter Connector ignition coil Solenoid valve Solenoid connector Allen screw M6x25 CPS connector Starter connector Cable tie ______________________________________________________ Effectivity: 125 MAX evo, Junior MAX...
  • Page 29 BRP-Rotax REPAIR MANUAL REMOVAL OF THE EXHAUST SYSTEM General Proceeds follows to dismantle the exhaust system: Procedure Step Removal of the exhaust system. See Chapter 9. REMOVAL OF RADIATOR WITH CAP ASSY. General Proceeds follows to dismantle the radiator with cap assy.:...
  • Page 30 BRP-Rotax REPAIR MANUAL REMOVAL OF THE FUEL LINE Safety instructions m WARNING Danger of explosion and ignition! Overflowing and spoilt gasoline must be absorbed immediately with a binding agent and correctly disposed. Do not work with open flames and sources of ignition. Fuel must not come into contact with hot parts such as engine or exhaust since this may cause a fire!.
  • Page 31 BRP-Rotax REPAIR MANUAL REMOVAL OF THE BOWDEN CABLE Instruction Proceed as follows to remove the Bowden cable: 1. Remove the carburetor cover (1). 2. Unscrew the nipple screw from the carburetor slide. 3. Disconnect the Bowden cable (2) from the nipple screw (3).
  • Page 32 BRP-Rotax REPAIR MANUAL Figure 3.6: Engine clamp (Illustration similar) Engine clamp ______________________________________________________ POSITIONING THE ENGINE ON THE TRESTLE MOUNTING PLATE General ATTENTION Do not use flammable liquids and aggressive cleaning agents to clean the engine. ENVIRONMENTAL NOTE Generally comply with standard rules for handling of chemicals. Dispose of chemicals as per local environmental regulations.
  • Page 33 BRP-Rotax REPAIR MANUAL Instructions Proceed as follows to position the engine on the trestle mounting plate: 1. Clean the engine and adjacent parts before the next step. 2. Unscrew the base plate from the engine, position the engine on the trestle mounting plate, and fix it securely with the 4 fixing screws.
  • Page 34 BRP-Rotax REPAIR MANUAL Chapter: Chapter 4 TOP END ENGINE COMPONENTS TOPICS IN THIS CHAPTER System description ..........................2 Cylinder removal .............................3 Removal of the spark plug........................4 Removal of the cylinder head cover ......................5 Removal of the thermostat ........................5 Removal of the combustion chamber insert .....................6 Removal of the exhaust socket .......................7...
  • Page 35 BRP-Rotax REPAIR MANUAL SYSTEM DESCRIPTION Overview Top End Components Figure 4.1: MAX evo engine shown in figure Cylinder Cylinder head cover Intake socket E-Rave cover Exhaust socket assy. Chapter 4 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo...
  • Page 36 BRP-Rotax REPAIR MANUAL CYLINDER REMOVAL General m WARNING Danger of severe burns and scalds! Always allow the engine to cool down to am- bient temperature before starting any work. Preparation The following preparation is required before removal: • Removal of the radiator and radiator hoses. See also Chapter 8.
  • Page 37 BRP-Rotax REPAIR MANUAL Figure 4.2: Cylinder Cylinder Gasket NOTE If only the components in the crankcase or the piston are to be replaced or in- spected, then the cylinder can be removed completely together with the following parts: • Cylinder head cover •...
  • Page 38 BRP-Rotax REPAIR MANUAL REMOVAL OF THE CYLINDER HEAD COVER Instruction Figure: Cylinder head cover. 1. Remove the cylinder head cover (1) by removing the 3 Allen screws (M6x25) (3) and 1 Allen screw M6x16 (4) from the cylinder. 2. Remove the cylinder head together with the o-ring (2).
  • Page 39 BRP-Rotax REPAIR MANUAL Figure 4.4: Thermostat Cylinder head cover Thermostat, 45 Degree celcius Compression spring Thermostat holder Thermostat retaining bracket TAPTITE screw M4x8 ______________________________________________________ REMOVAL OF THE COMBUSTION CHAMBER INSERT Instruction Figure: Combustion chamber insert. 1. Remove the combustion chamber insert (1) by unscrewing the 5 Hex screws M8x30 (4) with the lock washer (5) crosswise.
  • Page 40 BRP-Rotax REPAIR MANUAL Figure 4.5: Combustion chamber insert O-ring 64x2 Combustion chamber insert O-ring 23.3x2.4 Hex. screw M8x30 Lock washer A8 ______________________________________________________ REMOVAL OF THE EXHAUST SOCKET Instruction Figure: Exhaust socket. 1. Remove the exhaust socket (1) from the cylinder (5) by unscrewing the 2 Allen. screws (3).
  • Page 41 BRP-Rotax REPAIR MANUAL REMOVAL OF THE INTAKE SOCKET AND REED VALVE Instruction 1. Remove support bracket (3) and intake socket (4) by loosing the 5 Allen screws M6x25 (1) (2). 2. Remove the reed valve (5) and gasket (6) from the cylinder.
  • Page 42 BRP-Rotax REPAIR MANUAL Instruction Figure: Exhaust valve (RAVE) Proceed as follows to remove the exhaust valve: 1. Release the adjustment screw (1) with the O-ring (2) 2. Remove the 2 TAPTITE screws M5x25 (3). 3. Remove the valve cover (4) and the compression spring (5).
  • Page 43 BRP-Rotax REPAIR MANUAL REMOVAL OF THE PISTON General Figure: piston. ATTENTION In order to protect the piston pin circlip from unintentional loss, a suitable clean cloth should be used to cover the open cylinder bore in the crankcase. ATTENTION Always support the piston with the hand in order to avoid a bending moment or damage of the surface.
  • Page 44 BRP-Rotax REPAIR MANUAL CYLINDER COMPONENTS INSPECTION General ATTENTION Components, which have reached or exceeded their wear limits, must be replaced. Components, which are found to be defective in the context of the visual inspection and might influence the engine's performance, must also be replaced.
  • Page 45 BRP-Rotax REPAIR MANUAL INSPECTION OF PISTON AND PISTON RING Instructions Figure: Piston and piston ring. 1. Inspect the piston for cracks and signs of piston seizure. 2. Inspect the bore of the piston pin for damage and wear. 3. Inspect the piston pin ring groove for defects.
  • Page 46 BRP-Rotax REPAIR MANUAL INSPECTION OF THE PISTON DIAMETER Instructions 1. Measure the piston diameter with a micrometer (1). Conditions of measurement: room tem- perature = 20 °C, measuring point 20 mm from the lower edge of the piston, perpendicular to the piston pin axis.
  • Page 47 BRP-Rotax REPAIR MANUAL INSPECTION OF THE PISTON AND CYLINDER SIZING General NOTE Every new piston has the size classification and a production letter printed on the top of the piston (piston crown). NOTE Every new cylinder has the size classification stamped on the upper sealing surface.
  • Page 48 BRP-Rotax REPAIR MANUAL Piston classification “h” Piston labeling Tolerance field Minimum dimen- Maximum dimen- (mm) sion (mm) sion (mm) “h” 53.94 +0.015 / -0.015 mm 53.925 53.955 “h” 53.95 +0.015 / -0.015 mm 53.935 53.965 53.945 53.975 “h” 53.96 +0.015 / -0.015 mm “h”...
  • Page 49 BRP-Rotax REPAIR MANUAL INSPECTION OF THE SPARK PLUG Instructions Figure: Spark plug. 1. Inspect spark plug connector for cracks, burn-off, dampness and fouling. 2. Visual inspection of the spark plug for carbonization, oil fouling and discoloration of the electrode. • Pos. 1 = normal •...
  • Page 50 BRP-Rotax REPAIR MANUAL INSPECTION OF THE CYLINDER HEAD COVER Instructions Figure: Cylinder head cover. 1. Inspect cylinder head cover for cracks (visual inspection). 2. Inspect the contact surfaces of the two O-rings (1 and 2) for good condition (max. depth of wear 0.05 mm).
  • Page 51 BRP-Rotax REPAIR MANUAL Figure 4.16: Combustion chamber insert Combustion chamber Outside area Spark plug thread ______________________________________________________ INSPECTION OF THE EXHAUST SOCKET Instructions Figure: Exhaust socket. 1. Inspect the exhaust socket for damage or deformation. 2. Inspect exhaust gasket (2) for wear and replace if applicable.
  • Page 52 BRP-Rotax REPAIR MANUAL INSPECTION OF THE CARBURETOR FLANGE AND REED VALVE General ATTENTION The reed petal should be completely on the valve guide with a little initial tension (a gap should not be visible when held against the light. If applicable adjust reed valves more precisely by releasing the tightening torque of the screws.
  • Page 53 BRP-Rotax REPAIR MANUAL INSPECTION OF THE EXHAUST VALVE (125 MAX ONLY) Instructions See following figure. Preparation The following preparation is required before removal. 1. Clean oil or oil deposits from all parts with a suitable cleaning agent. 2. Check the smooth movement of the exhaust valve (1) in the cylinder, if applicable remove carbon deposits on the outlet valve and in the cylinder.
  • Page 54 BRP-Rotax REPAIR MANUAL CYLINDER COMPONENTS INSTALLATION INSTALLATION OF EXHAUST VALVE (125 MAX ONLY) NOTE Make sure that the components are installed in their correct position. Special tools The following special tools and equipment are required: Part no. Description 899788 LOCTITE 648...
  • Page 55 BRP-Rotax REPAIR MANUAL INSTALLATION OF EXHAUST VALVE, GASKET, VALVE ROD HOUSING Exhaust valve, Figure: Exhaust valve. gasket, valve rod housing 1. Insert exhaust valve into the slot in the cylinder head (1). Pay attention on the installation di- rection and make sure that the valve is not ranging into the exhaust port! 2.
  • Page 56 BRP-Rotax REPAIR MANUAL 3. Fit the bellows over the valve rod housing (1). The bead of the bellows must engage in the groove in the valve rod housing. 4. Tighten the exhaust valve piston (3) into the valve rod housing (1). Tightening torque 1.2 Nm (10.6 in.lb)
  • Page 57 BRP-Rotax REPAIR MANUAL INSTALLATION OF PISTON Special tools The following special tools and equipment are required: Description Field of application Part number 676035 Installation tool Piston n.a. Engine oil Piston pin NOTE Cover your eyes with safety goggles during this work! Mount the piston with the locking pin of the piston ring facing the intake port.
  • Page 58 BRP-Rotax REPAIR MANUAL NOTE Check that the circlip is correctly seated in the piston. Figure 4.23: Piston pin Circlip Needle cage K 15x19x20 Piston pin 15x10x12.5x45.6 Piston Mounting sleeve Installation tool ______________________________________________________ INSTALLATION OF THE CYLINDER General ATTENTION Use only the piston/cylinder pairings specified by the table in Chapter 4 Section 3.2.
  • Page 59 BRP-Rotax REPAIR MANUAL Instructions Proceed as follows to install the cylinder head: See Figure: Cylinder head. 1. Coat the stud bolts (1) on the longer thread end with LOCTITE 243 and screw into the crank- case. Tightening torque 5 Nm (44.25 in.lb).
  • Page 60 BRP-Rotax REPAIR MANUAL INSTALLATION OF THE EXHAUST SOCKET Special tools The following special tools and equipment are required: Part no. Description Field of application 297386 SILASTIC 732 Gasket Instructions Figure: Exhaust socket. Proceed as follows to install the exhaust socket: 1.
  • Page 61 BRP-Rotax REPAIR MANUAL ATTENTION The reed petal mounted on the reed valve must be fixed in precisely the correct installation position. Incorrect positioning of this valve leads to disturbed run- ning of the engine due to incomplete combustion. ATTENTION The reed petal is bent, not flat. It must be fixed with the concave facing the valve guide.
  • Page 62 BRP-Rotax REPAIR MANUAL INSTALLATION OF COMBUSTION CHAMBER INSERT General NOTE Note the installation position of the combustion chamber insert (2) - “Made in Aus- tria” points to the exhaust port. Instructions Figure: Combustion chamber insert. Proceed as follows to install the combustion chamber insert and cylinder head cover: 1.
  • Page 63 BRP-Rotax REPAIR MANUAL Instructions Figure: Coolant thermostat. Installation of the coolant thermostat: 1. Install thermostat (2) with collar nut M8 (3), compression spring (4) and thermostat retaining bracket (5) with 2 screws (6). Lock screws with LOCTITE 243. Figure 4.28: Coolant thermostat...
  • Page 64 BRP-Rotax REPAIR MANUAL Figure 4.29: Combustion chamber insert O-ring 23.3x2.4 O-ring 64x2 Cylinder head cover red Allen screw M6x25 ______________________________________________________ INSPECTION AND ADJUSTMENT OF SQUISH GAP General The gap between the piston in TDC (top dead center) and the combustion chamber insert is referred to as "squish gap".
  • Page 65 BRP-Rotax REPAIR MANUAL Instructions Figure: Squish gap measurement. 1. Rotate crankshaft by hand until the piston is approx. 5 mm below TDC. 2. Right thickness of solder 2.0 mm (for 125 Mini, Junior and Senior MAX) 3.0 mm (for 125 Micro MAX only) bend as shown in the Figure: “Squish gap measurement”...
  • Page 66 BRP-Rotax REPAIR MANUAL Figure 4.30: Squish gap measurement Vernier caliper Solder ______________________________________________________ INSTALLATION OF SPARK PLUG Instructions Proceed as follows to install the spark plug: 1. Screw in spark plug hand-tight and use tightening torque to tighten it with 27 Nm (20 ft.lb).
  • Page 67 BRP-Rotax REPAIR MANUAL NOTES Page 34 Effectivity: 125 MAX evo, Junior MAX November 01 2021 evo, Mini MAX evo, Micro MAX evo...
  • Page 68 BRP-Rotax REPAIR MANUAL Chapter: Chapter 5 BOTTOM END ENGINE COMPONENTS TOPICS IN THIS CHAPTER System description ..........................2 Disassembly of the balance drive and water pump gears ................5 Drain oil ..............................5 Removal of the gear cover and gears ....................6 Disassembling the crankcase........................9 Removal of main bearings and oil seals ....................
  • Page 69 BRP-Rotax REPAIR MANUAL SYSTEM DESCRIPTION Overview Figure 5.1: Position on the engine Chapter 5 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo Page 2 November 01 2021...
  • Page 70 BRP-Rotax REPAIR MANUAL Overview Components of crankcase Figure 5.2 Sealing ring A 6x10 Allen screw M6x25 Allen screw M6x30 Gearbox cover Retaining ring with lug 20x1.2 Gasket Water pump gear 19 T Locating pin 8 small M6x40 Idle gear 28/13 T Water pump pinion 16 T Needle pin 4x15.8...
  • Page 71 BRP-Rotax REPAIR MANUAL Countersunk screw M5x12 Thrust washer O-ring 18x3.5 Crank case assy. black Crank case assy. Gasket Allen screw M6x45 Allen screw M6x60 Needle bushing 8x12x8 Oil seal AS 25x38x7 Stud M8x57/20 Stud M8x28/20 Ball bearing 6302 Ball bearing 6206 Ball bearing 6005 Crankshaft assy.
  • Page 72 BRP-Rotax REPAIR MANUAL DISASSEMBLY OF THE BALANCE DRIVE AND WATER PUMP GEARS Safety information m WARNING Danger of severe burns and scalds! Always allow the engine to cool down to am- bient temperature before starting any work. Preparation The following preparation is required before removal: 1.
  • Page 73 BRP-Rotax REPAIR MANUAL Figure 5.3: Drain oil Sealing ring A6x10 Gearbox cover Allen screw M6x25 ______________________________________________________ REMOVAL OF THE GEAR COVER AND GEARS Special tools The following special tools and equipment are required: Part no. Description n.a. Circlip pliers Drive wheel n.a.
  • Page 74 BRP-Rotax REPAIR MANUAL Figure 5.4: Gearbox cover Sealing ring A 6x10 Allen screws Gear cover Gasket ______________________________________________________ Instruction Figure: Water pump and balance shaft. 3. Remove water-pump pinion (2) and idle gear (5). 4. Remove needle pins (3) and thrust washer (4) from the water-pump shaft.
  • Page 75 BRP-Rotax REPAIR MANUAL Figure 5.5: Water pump and balance gears Idle gear 28/13 T Water pump pinion 16T Needle pin 4x15.8 Thrust washer Retaining ring with lug 20x1.2 Water pump gear 19 T Balance gear 50 T Balance gear 50T O-ring 18x3.5...
  • Page 76 BRP-Rotax REPAIR MANUAL DISASSEMBLING THE CRANKCASE Special tools The following special tools and equipment are required: Part no. Description Field of application 276016 Puller assembly Case halves n.a. Plastic hammer Crankshaft Instructions Figure: Crankcase. NOTE Use two hex. screws to separate the case halves 1.
  • Page 77 BRP-Rotax REPAIR MANUAL Instruction Figure: Balance shaft. 4. Remove gasket (2) from the case half (1). 5. Remove water-pump shaft (4). 6. Remove balance shaft (3) from the case. Figure 5.7: Balance shaft Crankcase half Gasket Water pump shaft Balance shaft ______________________________________________________ 7.
  • Page 78 BRP-Rotax REPAIR MANUAL Figure 5.8: Crankcase Crankshaft Crankcase half Plastic hammer ______________________________________________________ REMOVAL OF MAIN BEARINGS AND OIL SEALS Special tools The following special tools and equipment are required: Part no. Description n.a. Convection oven Case halves 676030 Installation tool...
  • Page 79 BRP-Rotax REPAIR MANUAL Figure 5.9: Bearing and oil seal for crankshaft Oil seal AS 28x38x7 Oil seal AS 25x38x7 Pick up sensor Oil seal A 10x26x7 Allen screw M6x20 Air vent screw M18x1.5 Countersunk screw M5x12 Thrust washer ______________________________________________________ m WARNING...
  • Page 80 BRP-Rotax REPAIR MANUAL Figure 5.10: Drivetrain side of the crankcase Crank case assy. Ball bearing 6206 Ball bearing 6302 Installation tool part no. 676030 Needle bushing 8x12x8 Tube ______________________________________________________ BALANCE DRIVE SIDE OF THE CRANKCASE NOTE The wooden board must have cutouts for the two dowels (1) and the locating pin (2) to form a flat base for the case half.
  • Page 81 BRP-Rotax REPAIR MANUAL Figure 5.11: Balance drive side of the crankcase Locating pin 8 small M6x40 Pin 8x12 Crankcase assy. Ball bearing 6206 Ball bearing 6005 ______________________________________________________ Chapter 5 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo...
  • Page 82 BRP-Rotax REPAIR MANUAL INSTALLATION OF THE CRANKSHAFT REPAIR KIT DISASSEMBLING OF THE CRANKSHAFT Safety instructions m WARNING Non-compliance can result in serious injuries or death! Be particularly careful when working with a tool such as a hydraulic press, and follow the instructions of the manufacturer.
  • Page 83 BRP-Rotax REPAIR MANUAL Figure 5.12: Crankshaft repair jig Part Part no. Function Bottom section of the repair jig Top section of the repair jig Thrust plate 276051 or 276052 Sleeve Thrust ring Crowbar Thrust pin/old piston pin NOTE Con rod parts are not part of the crankshaft repair jig.
  • Page 84 BRP-Rotax REPAIR MANUAL Part Part no. Description 685011 Crankshaft repair kit (1x) consisting of: n.a. Con rod (1x) n.a. Con rod pin (1x) n.a. Needle bearing (1x) n.a. Thrust washers (2x) Figure 5.13: Con rod parts Con rod pin Con rod...
  • Page 85 BRP-Rotax REPAIR MANUAL 1. Push thrust plate (2) between the two halves of the crankshaft. Figure 5.14 Crankshaft repair jig (tool) Thrust plate Drive side of the crankshaft half ______________________________________________________ 2. Position the crankshaft on the thrust plate (2) on bottom section of the tool (1) and make sure that the crankshaft matches the bore in the bottom section at the crankshaft repair jig (1).
  • Page 86 BRP-Rotax REPAIR MANUAL Figure 5.15 Crankshaft repair jig (tool) Thrust plate Thrust pin Drive side of the crankshaft half ______________________________________________________ 3. Position the stamp of the press with a diameter of 10 mm or the thrust pin (4) on the connect- ing rod pin and press the crankshaft apart.
  • Page 87 BRP-Rotax REPAIR MANUAL Figure 5.16 Con rod pin Con rod ______________________________________________________ 5. Take the gearbox-end of the crankshaft half (other half) and press the crank pin out completely. Chapter 5 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo...
  • Page 88 If one of the wear limits CS01 or CS02 is reached, the complete crankshaft must be replaced. NOTE If one of the wear limits CS03, CS04 or CS05 is reached, BRP-Rotax recom- mends use of the applicable repair kit. See also Chapter 5 Figure: Con rod parts. NOTE If the maximum approved stroke (CS06) of the crankshaft is exceeded, the crank- shaft must be realigned.
  • Page 89 BRP-Rotax REPAIR MANUAL Figure 5.17 Description New dimension Wear limit Code Main bearing seat CS01 29.980 mm - 29.94 mm 29.995 mm Clutch bearing seat CS02 14.98 mm - 15.003 14.95 mm Piston pin bearing seat CS03 18.99 mm - 19.005 19.015 mm...
  • Page 90 BRP-Rotax REPAIR MANUAL Description Code New dimension Wear limit Distance of crank webs CS07 48.95 mm - 49.05 Thrust washer thickness CS08 1.0 mm - 1.07 mm CRANKSHAFT NOT IN SPECIFICATION General NOTE If the crankshaft is not 100% aligned or exceeds the tolerance, the crankshaft must be re-aligned to fit the measurements CS04 until CS07 by following the in- structions below.
  • Page 91 BRP-Rotax REPAIR MANUAL Figure 5.19: Aluminum hammer Crankshaft half Crankshaft Aluminum hammer ______________________________________________________ CRANKSHAFT - ASSEMBLY General NOTE Clean the bore for the connecting rod pins of the gearbox-side crankshaft half with a cleaning agent (grease-free). Special tools The following special tools and equipment are required: Part no.
  • Page 92 BRP-Rotax REPAIR MANUAL 4. Position the drive end crankshaft half (3) into the crankshaft repair jig (1) and press the new con rod pin (4) into the crankshaft until the con rod pin stops moving, then remove the sleeve (2).
  • Page 93 BRP-Rotax REPAIR MANUAL Figure 5.21 Con rod pin Con rod assy. with cage ______________________________________________________ Instructions Figure: Crankshaft assembly. 6. Slide the gearbox-end crankshaft half (1) into the bottom section of the tool (2). 7. Clean the drive end crankshaft web hole with cleaning agent (grease-free).
  • Page 94 BRP-Rotax REPAIR MANUAL Figure 5.22 Crankshaft half (engine end) Bottom section of the repair jig Con rod pin Con rod ______________________________________________________ 9. Slide the drive-end crankshaft half (1) into the top section of the repair jig (2) and hold it by hand or with help of the M6 threaded pin (276052 only), so that it won't fall out when rotating upside down.
  • Page 95 BRP-Rotax REPAIR MANUAL Figure 5.23: Crankshaft assembly Press stamp Bottom section of the repair jig Top section of the repair jig Thrust ring ______________________________________________________ Chapter 5 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo Page 28...
  • Page 96 BRP-Rotax REPAIR MANUAL Figure 5.24: Measurement of crank webs CS 07 = 49 mm (+ 0.05 / - 0.05) ______________________________________________________ Effectivity: 125 MAX evo, Junior MAX Chapter 5 evo, Mini MAX evo, Micro MAX evo Page 29 November 01 2021...
  • Page 97 BRP-Rotax REPAIR MANUAL CRANKCASE INSPECTION INSPECTION OF WATER PUMP DRIVE Instructions Figure: Water pump drive. 1. Inspect water pump gear (1), idle gear (2) and water pump pinion (3) for any kind of wear (visual inspection). 2. Inspect the hole and the two axial surfaces of the idle gear (2) for signs of wear.
  • Page 98 BRP-Rotax REPAIR MANUAL INSPECTION OF WATER PUMP SHAFT Instruction Figure: Water pump shaft. 1. Check the water pump shaft in the areas around the two shaft seal rings; if it is excessively worn it must be replaced. 2. Check the impeller for damage and/or any abnormal deformation, and replace it if necessary.
  • Page 99 BRP-Rotax REPAIR MANUAL Figure 5.27: Balance shaft drive Balance gear 50 T O-ring 18x3.5 Crankshaft assy. Balance shaft ______________________________________________________ INSPECTION OF BALANCE SHAFT General NOTE If one of the wear limits BS10 or BS11 is reached, the balance shaft must be replaced.
  • Page 100 BRP-Rotax REPAIR MANUAL Figure 5.28: Balance shaft INSPECTION OF THE HOUSING HALVES Instructions Figure: Crankcase. 1. Clean both case halves with commercial detergents. 2. Check both halves (1) for cracks and damage (visual inspection). 3. Check sealing surfaces (2) for damage (visual inspection).
  • Page 101 BRP-Rotax REPAIR MANUAL CRANKCASE - ASSEMBLY General NOTE Always replace old gaskets, circlips, O-rings and oil seals with new ones after disassembling. Special tools The following special tools and equipment are required: Part no. Description n.a. Convection oven or heating...
  • Page 102 BRP-Rotax REPAIR MANUAL Figure 5.30: Oil seal installation Mounting tool part no. 676010 Oil seal AS 28x38x7 ______________________________________________________ Instruction Figure: Ball bearing. 5. Slide the ball bearing (1) of the crankshaft into the crankcase half to the limit stop so the closed side of the cage is facing to the crankshaft.
  • Page 103 BRP-Rotax REPAIR MANUAL Instruction Figure: Needle bushing. 7. Press in the needle bushing 8x12x8 (1) to the limit stop with the installation tool (2) (part no. 676030) so the label on the needle bearing is facing outwards. 8. Allow both crankcase halves to cool to room temperature (about 20 °C / 274 °F).
  • Page 104 BRP-Rotax REPAIR MANUAL Figure 5.33: Ball bearing, oil seal Ball bearing 6005 Thrust washer Countersunk screw M5x12 Oil seal AS 28x38x7 Insertion sleeve (part no. 676010) ______________________________________________________ Instruction Figure: Insertion jig. 6. Rotate crankcase half. 7. Slide the ball bearing (1) of the crankshaft into the crankcase half to the limit stop so the closed side of the cage is facing to the crankshaft.
  • Page 105 BRP-Rotax REPAIR MANUAL Figure 5.34: Insertion jig Ball bearing 6206 Oil seal 10x26x7 Insertion jig Oil seal 10x26x7 (open end) ______________________________________________________ Chapter 5 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo Page 38 November 01 2021...
  • Page 106 BRP-Rotax REPAIR MANUAL ASSEMBLY OF CRANKSHAFT, WATER PUMP SHAFT AND BALANCE SHAFT Special tools The following special tools and equipment are required. Part no. Description Field of application 297434 LOCTITE Anti-Seize Balance shaft, crankshaft Instruction Figure: Crankshaft, Balancs shaft, Water pump shaft 1.
  • Page 107 BRP-Rotax REPAIR MANUAL ASSEMBLY OF THE CRANKCASE General NOTE When using new studs for the assembly of the cylinder, first screw the long side of the threaded studs into the housing and secure them with LOCTITE 243. Tightening torque 10 Nm.
  • Page 108 BRP-Rotax REPAIR MANUAL INSTALLATION OF CRANKCASE ASSY. Final tasks 1. Install cylinder assy. See Chapter 4). 2. Install balance drive and centrifugal clutch. See Chapter 7). 3. Take the engine off the assembly stand. See Chapter 3). 4. Install the engine in the kart chassis. See Chapter 3).
  • Page 109 BRP-Rotax REPAIR MANUAL Figure 5.37: Crankcase O-ring 18x3.5 Crankshaft Balance shaft gear Balance gear Balance shaft gear Positioning marking TDC position marking ______________________________________________________ Instruction Figure: Idle gear. 5. Slide the water pump gear (1) onto the crankshaft. ATTENTION Do not bend the retaining ring during installation.
  • Page 110 BRP-Rotax REPAIR MANUAL Figure 5.38: Idle gear Water pump gear 19 T Retaining ring with lug 20x1.2 Needle pin 4x15.8 Thrust washer 10.1/17/1 Water pump pinion 16 T Locating pin 8 small M6x40 Idle gear 28/13 T ______________________________________________________ 10. Position new gasket (1) on the case.
  • Page 111 BRP-Rotax REPAIR MANUAL Figure 5.39 Gasket Gearbox cover Sealing ring A 6x10 Allen screw M6x25 Allen screw M6x30 ______________________________________________________ Chapter 5 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo Page 44 November 01 2021...
  • Page 112 BRP-Rotax REPAIR MANUAL Chapter: Chapter 6 CARBURETOR AND INTAKE SILENCER TOPICS IN THIS CHAPTER System description ..........................2 Removal of the carburetor and intake silencer ..................3 Removal of the carburetor and intake silencer ..................3 Removal of the fuel pump........................4 Disassembly of the carburetor ........................5 Disassembly of the intake silencer ......................7...
  • Page 113 BRP-Rotax REPAIR MANUAL SYSTEM DESCRIPTION Overview Position on engine Figure 6.1: Position on engine, TYPICAL (Figure shows 125 MAX evo engine) Intake silencer Carburetor Fuel pump Chapter 6 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo...
  • Page 114 BRP-Rotax REPAIR MANUAL REMOVAL OF THE CARBURETOR AND INTAKE SILENCER Safety instructions m WARNING Danger of explosion and ignition! Overflowing and spoilt gasoline must be absorbed immediately with a binding agent and correctly disposed. Do not work with open flames and sources of ignition. Fuel must not come into contact with hot parts such as engine or exhaust since this may cause a fire!.
  • Page 115 BRP-Rotax REPAIR MANUAL Figure 6.2: Carburetor and intake silencer Impulse line Fuel line to the carburetor Fuel pump Carburetor Support bracket Allen screw M6x25 Pipe clamp 51 Intake silencer ______________________________________________________ REMOVAL OF THE FUEL PUMP Instruction Figure: Fuel pump. To remove the fuel pump the following steps are required: 1.
  • Page 116 BRP-Rotax REPAIR MANUAL Figure 6.3: Fuel pump Fuel pump Support bracket Lock nut M6 Washer 6.4 Allen screw M6x20 ______________________________________________________ DISASSEMBLY OF THE CARBURETOR 1. Disassembly of the carburetor to the parts shown in Figure: Carburetor and clean them with fuel.
  • Page 117 BRP-Rotax REPAIR MANUAL Figure 6.4: Carburetor Chapter 6 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo Page 6 November 01 2021...
  • Page 118 BRP-Rotax REPAIR MANUAL DISASSEMBLY OF THE INTAKE SILENCER Intake silencer Figure: Intake silencer. 1. Disassemble the intake silencer to the parts shown in following Figure. Figure 6.5: Intake silencer Intake silencer case Intake silencer cover Filter element support/holder Intake silencer tube...
  • Page 119 BRP-Rotax REPAIR MANUAL CARBURETOR AND INTAKE SILENCER – INSPECTION OF COMPONENTS In the case of problems with the fuel supply the carburetor should be checked: First the components should be cleaned and then inspected. INSPECTION OF THE CARBURETOR Instruction Figure: Carburetor.
  • Page 120 BRP-Rotax REPAIR MANUAL INSPECTION OF THE FUEL PUMP General NOTE Only the complete membrane and gasket set of the fuel pump can be replaced. Fuel pump gasket set: Part no. 296165 Instruction Figure: Fuel pump. 1. Check the condition of the impulse pipe (1), fuel line (2) and fuel overflow line (3) and in case of doubt replace them.
  • Page 121 BRP-Rotax REPAIR MANUAL Figure 6.8: Intake silencer Intake silencer case Intake silencer cover Filter element support/holder Intake silencer tube Support bracket Filter element Washer 6.4 Allen screw M6x20 Nut M6 ______________________________________________________ Chapter 6 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo...
  • Page 122 BRP-Rotax REPAIR MANUAL INSTALLING THE CARBURETOR AND INTAKE SILENCER ASSEMBLY OF CARBURETOR Instruction NOTE Use ROTAX® gasket set, part no. 293834. 1. Assemble the components in the opposite succession as you disassembled them. See also Chapter 6) section: Disassembly of the carburetor.
  • Page 123 BRP-Rotax REPAIR MANUAL ASSEMBLY OF INTAKE SILENCER General NOTE Before assembly, first immerse the filter element in filter oil. Squeeze out excess oil. Instruction The following steps are required to install the intake silencer: 1. Assemble the components in the opposite succession as you disassembled them. See also Chapter 6.
  • Page 124 BRP-Rotax REPAIR MANUAL INSTALLATION OF FUEL PUMP, CARBURETOR Safety instructions m WARNING Danger of explosion and ignition! Overflowing and spoilt gasoline must be absorbed immediately with a binding agent and correctly disposed. Do not work with open flames and sources of ignition. Fuel must not come into contact with hot parts such as engine or exhaust since this may cause a fire!.
  • Page 125 BRP-Rotax REPAIR MANUAL Instruction To install the carburetor and intake silencer the following steps are required: Figure: Carburetor and intake silencer. 1. Pull the hose clamp (3) over the carburetor flange. 2. Push the carburetor (1) onto the carburetor flange (2) and fasten the hose clamp (3).
  • Page 126 BRP-Rotax REPAIR MANUAL Chapter: Chapter 7 CENTRIFUGAL CLUTCH, PRIMARY AND BALANCE DRIVE TOPICS IN THIS CHAPTER System description ..........................2 Removal of the clutch and starter gear assy....................4 Removal of the centrifugal clutch assy.....................4 Removal of the electric starter ........................4 Removal of the clutch drum ........................5...
  • Page 127 BRP-Rotax REPAIR MANUAL SYSTEM DESCRIPTION Overview Position on engine Figure 7.1: Clutch and starter gear assy. Starter gear assy. Clutch drum Sprocket ______________________________________________________ Chapter 7 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo Page 2...
  • Page 128 BRP-Rotax REPAIR MANUAL Overview Components of clutch and starter assy. Figure 7.2 Chain protection Allen screw M6x25 Hex. nut M10x1 Thrust washer Sprocket Clutch drum Plain bearing (11T sprockets) or needle Needle pin 5x5 cage (all other sprockets) O-ring Hex. nut 28x1 Thrust washer 15.2...
  • Page 129 BRP-Rotax REPAIR MANUAL REMOVAL OF THE CLUTCH AND STARTER GEAR ASSY. REMOVAL OF THE CENTRIFUGAL CLUTCH ASSY. Safety instructions m WARNING Danger of severe burns and scalds! Always allow the engine to cool down to am- bient temperature before starting any work.
  • Page 130 BRP-Rotax REPAIR MANUAL REMOVAL OF THE CLUTCH DRUM Special tools The following special tools and equipment are required: Part no. Description 277381 Locking tool Spark plug thread 676205 Fixation tool assy. Starter gear assy. Preparation • Remove the chain protection (1).
  • Page 131 BRP-Rotax REPAIR MANUAL Figure 7.5 Fixation tool assy. Fixation tool for crankshaft ______________________________________________________ 4. Unscrew and remove hex nut (1). 5. Remove thrust washer (2), clutch drum with sprocket (3), needle cage (4) O-ring (5) and thrust washer 15.2 (6).
  • Page 132 BRP-Rotax REPAIR MANUAL Figure 7.6 Hex. nut M10x1 Thrust washer Needle cage / Plain bearing Clutch drum O-ring Thrust washer 15.2 ______________________________________________________ REMOVAL OF THE SPROCKET Instruction Figure: Fixation tool 1. Fix fixation tool for sprocket (1) in a vise.
  • Page 133 BRP-Rotax REPAIR MANUAL Figure 7.7: Fixation tool Sprocket Fixation tool Needle pin 5x5 Clutch drum Hex. nut ______________________________________________________ REMOVAL OF THE STARTER GEAR ASSY. Special tools The following special tools and equipment are required: Part no. Description Field of application 276016 Puller assy.
  • Page 134 BRP-Rotax REPAIR MANUAL Figure 7.8: Fixation tool Fixation tool (crankshaft) Fixation tool (starter gear) ______________________________________________________ 3. Remove the clutch (3). 4. Unscrew hex. nut M20 (4). Figure 7.9: Clutch Clutch Allen screw M6x12 Hex. nut M28x1 ______________________________________________________ Effectivity: 125 MAX evo, Junior MAX...
  • Page 135 BRP-Rotax REPAIR MANUAL 5. Fasten the puller assy. (1) to the starter gear assembly with 3 Allen screws M6x60 (2). NOTE Make sure the screws do not touch the housing. Do not screw them in too far. 6. Pull out starter gear assy. (3).
  • Page 136 BRP-Rotax REPAIR MANUAL INSPECTION OF CLUTCH AND STARTER GEAR ASSY. INSPECTION OF THE CLUTCH DRUM General If the clutch drum starts to tumble when the engine is idling with a sprocket with 11 teeth, this indicates a worn out bearing. Please replace the bearing immediately.
  • Page 137 BRP-Rotax REPAIR MANUAL Instructions Figure: Starter reduction gear assy. 1. Clean starter reduction gear assy. (1). 2. Inspect the gear wheels (2) for wear. 3. Inspect the operation of the starter reduction gear assy. Figure 7.12: Starter reduction gear assy.
  • Page 138 BRP-Rotax REPAIR MANUAL Figure 7.13: Electric starter Starter cable Teeth INSPECTION OF THE CLUTCH AND STARTER GEAR ASSY. Instructions Figure: Clutch and starter gear assy. 1. Check the hole (1) in the clutch (2). 2. Check the teeth of the starter gear assy. (3) for damage or deformation.
  • Page 139 BRP-Rotax REPAIR MANUAL ELECTRIC STARTER REPAIR KIT Special tools The following special tools and equipment are required: Part no. Description 281262 Electric starter repair kit Electric starter Instructions Figure: Electric starter 1. Remove the starter housing from the crankcase and gearbox case by unscrewing 2 Allen screws.
  • Page 140 BRP-Rotax REPAIR MANUAL 1. Secure the rotor shaft with a suitable tool. 2. Pull out solenoid housing. 3. Pull the rotor shaft from the starter motor support. 4. Unscrew the bracket for the positive contact. 5. Press out the rubber grommet.
  • Page 141 BRP-Rotax REPAIR MANUAL 4. Secure the plastic ring with two Phillips head screws and washers. The fixing provides the ground contact. 5. Install the rubber grommet over the positive contact. 6. Secure the bracket on the starter motor support. 7. Insert the coil springs in the cutouts of the plastic ring, press the brushes against them.
  • Page 142 BRP-Rotax REPAIR MANUAL INSTALLATION OF CLUTCH AND STARTER GEAR ASSY. General Follow the sequence exactly. The starter reduction gear assy. cannot be installed after in- sertion of the starter gear assy. INSTALLATION OF THE STARTER REDUCTION GEAR ASSY. Special tools The following special tools and equipment are required: Part no.
  • Page 143 BRP-Rotax REPAIR MANUAL Instructions 1. Preferred version 1: screw in fixation tool for crankshaft (1) into the spark plug thread till the end stop. Figure 7.18: Fixation tools Fixation tool (crankshaft) Fixation tool (starter gear) ______________________________________________________ 2. Version 2: insert fixation tool assy. (3) into the starter gear assy. (1).
  • Page 144 BRP-Rotax REPAIR MANUAL Figure 7.19: Starter gear assy. Starter gear assy. Hex. nut M28x1 Fixation tool (starter gear) Clutch Allen screw M6x12 ______________________________________________________ ASSEMBLY OF THE CLUTCH DRUM INSTALLATION OF THE SPROCKET Special tools The following special tools and equipment are required: Part no.
  • Page 145 BRP-Rotax REPAIR MANUAL Figure 7.20: Fixation tool Sprocket Fixation tool Needle pin Clutch drum Hex. nut. ______________________________________________________ INSTALLATION OF BEARING SLEEVE (FOR SPROCKETS WITH 11 TEETH ONLY) Special tools The following special tools and equipment are required: Part no. Description...
  • Page 146 BRP-Rotax REPAIR MANUAL Figure 7.21: Installation of bearing sleeve Bearing sleeve Beveled edge Clutch drum ______________________________________________________ INSTALLATION OF THE CLUTCH DRUM Safety m WARNING Risk of fatal injury! The engine must not be started without a clutch drum. Special tools The following special tools and equipment are required: Part no.
  • Page 147 BRP-Rotax REPAIR MANUAL 7. Remove fixation tools for crankshaft and/or the starter gear assy. Figure 7.22: Clutch drum Hex. nut Thrust washer Clutch drum with sprocket Needle cage O-ring Thrust washer 15.2 ______________________________________________________ 8. Lubricate starter reduction gear assy. in the area shown in the following figure.
  • Page 148 BRP-Rotax REPAIR MANUAL Figure 7.23: Chain protection Chain protection Allen screw M6x25 ______________________________________________________ INSTALLATION OF THE ELECTRIC STARTER Instructions 1. Lubricate O-ring (2) on the center of the electric starter (1). Figure 7.24 O-ring Electric starter ______________________________________________________ 2. Install starter support (2) with electric starter (1) using 2 Allen screws M6x35 (5). Tightening torque 10 Nm (89 in.
  • Page 149 BRP-Rotax REPAIR MANUAL NOTE Push the electric starter (1) into the centering of the housing (3) by rotating it back and forth until the teeth of the electric starter are meshed with the teeth of the starter reduction gear assy.
  • Page 150 BRP-Rotax REPAIR MANUAL FILLING GEARBOX WITH OIL General NOTE Take a measuring cup and fill with 100 ml of XPS® KART TEC GEAR OIL Special tools The following special tools/equipment are required: Part no. Description Field of application 25473 XPS® KART TEC GEAR...
  • Page 151 BRP-Rotax REPAIR MANUAL NOTES Page 26 Effectivity: 125 MAX evo, Junior MAX November 01 2021 evo, Mini MAX evo, Micro MAX evo...
  • Page 152 BRP-Rotax REPAIR MANUAL Chapter: Chapter 8 COOLING SYSTEM TOPICS IN THIS CHAPTER System description ..........................2 Removal of radiator ..........................4 Removal of the cooling water hose ......................4 Inspection of cooling system ........................6 Radiator – inspection of components ......................6 Installing the radiator ..........................7 Installation of the cooling water hoses .....................7...
  • Page 153 BRP-Rotax REPAIR MANUAL SYSTEM DESCRIPTION Overview Figure 8.1: Radiator Cooling water hose Radiator Hose clamp. ______________________________________________________ Chapter 8 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo Page 2 November 01 2021...
  • Page 154 BRP-Rotax REPAIR MANUAL Overview Figure 8.2: Water pump Radiator (Max evo, Junior evo, Mini Radiator cap with gasket evo) Windshield (Max evo, Junior evo, Mini Allen screw M6x16 with rounded flange evo) head Washer 6.4 Lock nut M6 Radiator bracket (Max evo, Junior evo,...
  • Page 155 BRP-Rotax REPAIR MANUAL REMOVAL OF RADIATOR Safety instructions m WARNING Danger of severe burns and scalds! Always allow the engine to cool down to am- bient temperature before starting any work. Preparation The following preparations should be carried out before removing the components: 1.
  • Page 156 BRP-Rotax REPAIR MANUAL Figure 8.3: Cooling water hoses Hose clamps Hoses Allen screw M8x75 Lock washer A8 ______________________________________________________ Effectivity: 125 MAX evo, Junior MAX Chapter 8 evo, Mini MAX evo, Micro MAX evo Page 5 November 01 2021...
  • Page 157 BRP-Rotax REPAIR MANUAL INSPECTION OF COOLING SYSTEM RADIATOR – INSPECTION OF COMPONENTS Instruction Figure: Radiator. NOTE If some of the cooling fins are slightly bent, they may be gently bent back into shape. 1. Use compressed air to remove dirt from the cooling fins of the radiator. Never use a high- pressure cleaner.
  • Page 158 BRP-Rotax REPAIR MANUAL INSTALLING THE RADIATOR INSTALLATION OF THE COOLING WATER HOSES Preparation 1. Mount radiator bracket (5) on radiator through the holes with rubber grommets and tighten with Allen srew M6x20 and washer 6.2. Figure 8.5: Preparation for radiator installation...
  • Page 159 BRP-Rotax REPAIR MANUAL Figure 8.6: Installation of cooling water hoses Cooling water hoses Radiator connection Hose clamps Radiator cap ______________________________________________________ INSTALLATION OF THE RADIATOR ON ENGINE Instructions Figure: Installation of the radiator on engine 1. Install radiator with pre-mounted radiator bracket (3) on engine an tighten with Allen screw M8x75 (2) and Lock washer A8 (1).
  • Page 160 BRP-Rotax REPAIR MANUAL Figure 8.7: Installation of the radiator on engine Lock washer A8 Allen screw M8x75 Radiator with radiator bracket ______________________________________________________ Effectivity: 125 MAX evo, Junior MAX Chapter 8 evo, Mini MAX evo, Micro MAX evo Page 9 November 01 2021...
  • Page 161 BRP-Rotax REPAIR MANUAL FINAL TASKS Instructions 1. Using a funnel, pour the specified amount of coolant into the filling opening of the radiator. 2. Close the radiator cap. 3. Check that the cooling system is leak-free by warming up the engine.
  • Page 162 BRP-Rotax REPAIR MANUAL Chapter: Chapter 9 EXHAUST SYSTEM TOPICS IN THIS CHAPTER System description ..........................2 Removal of the exhaust system.......................4 Checking the exhaust system .........................5 Disassembling the exhaust system ......................5 Assembling the exhaust system......................5 Installation of the exhaust system ......................6 Preparation for installation ........................7...
  • Page 163 BRP-Rotax REPAIR MANUAL SYSTEM DESCRIPTION Overview Position on the engine Figure 9.1 Exhaust muffler assy. Silencer assy. Exhaust socket assy. ______________________________________________________ Chapter 9 Effectivity: 125 MAX evo, Junior MAX evo, Mini MAX evo, Micro MAX evo Page 2 November 01 2021...
  • Page 164 BRP-Rotax REPAIR MANUAL Overview Exhaust system Figure 9.2 Exhaust socket Exhaust gasket Spring stainless assy. Exhaust muffler Silencer assy. Isolating mat assy. Perforated tube Exhaust gasket Spring stainless assy. Silencer assy. Tension springs Isolating mat, MICRO MICRO Perforated tube Washer 8.4 stain- Lock nut M8, MICRO assy.
  • Page 165 BRP-Rotax REPAIR MANUAL REMOVAL OF THE EXHAUST SYSTEM Safety instructions m WARNING Danger of severe burns and scalds! Always allow the engine to cool down to am- bient temperature before starting any work. Special tools The following special tools and equipment are required: Part no.
  • Page 166 BRP-Rotax REPAIR MANUAL CHECKING THE EXHAUST SYSTEM ATTENTION A worn isolating mat has a major engine damage as result! Instructions See Figure 1. Check exhaust system for cracks, bending or other damages. Replace if necessary. 2. Clean the ball socket of combustion residue and inspect for wear.
  • Page 167 BRP-Rotax REPAIR MANUAL Figure 9.4: Exhaust system Exhaust muffler assy. Silencer assy. Isolating mat Perforated tube assy. Lock nut M4 Allen screw M4x12 Exhaust gasket Spring stainless Tension spring ______________________________________________________ INSTALLATION OF THE EXHAUST SYSTEM Instructions For installation of the exhaust system, see latest Installation Manual for the engine type 125 MAX evo.
  • Page 168 BRP-Rotax REPAIR MANUAL PREPARATION FOR INSTALLATION Safety instructions ATTENTION All parts must always be clean and in good condition. Clean and inspect disassembled parts and assemble them in accordance with the in- structions. Inspect surfaces, bores and threads for damage.
  • Page 169 BRP-Rotax REPAIR MANUAL Instructions Proceed as follows to install the fuel line: 1. The installation of the fuel line is identical to the removal, but in reverse order. See also INSTALLATION OF THE BOWDEN CABLE Instructions Proceed as follows to install the bowden cable: 1.
  • Page 170 BRP-Rotax REPAIR MANUAL Figure 9.5: Ignition unit Spark plug connector Ignition coil Crankshaft positioning sensor (CPS) Electric starter Connector ignition coil Solenoid valve Solenoid connector Allen screw M6x25 CPS connector Starter connector Cable tie ______________________________________________________ INSTALLATION OF THE EXHAUST SYSTEM...
  • Page 171 BRP-Rotax REPAIR MANUAL NOTES Page 10 Effectivity: 125 MAX evo, Junior MAX November 01 2021 evo, Mini MAX evo, Micro MAX evo...
  • Page 172 BRP-Rotax REPAIR MANUAL Index Abbreviations............2 Filling gearbox with oil .........25 Assembling of electric starter .......15 Final tasks ............10 Assembling the exhaust system ......5 Assembly of carburetor........11 Assembly of crankshaft, water pump shaft and balance shaft ............39 General note............2 Assembly of float housing ........11 Assembly of housing halves.........40...
  • Page 173 BRP-Rotax REPAIR MANUAL Installation of spark plug ........33 Removal of the centrifugal clutch assy.....4 Installation of the bowden cable......8 Removal of the clutch and starter gear assy.....4 Installation of the carburetor flange and reed Removal of the clutch drum........5 valve ..............27 Removal of the combustion chamber insert .....6...

This manual is also suitable for:

Rotax 125 junior max evoRotax 125 mini max evoRotax 125 micro max evo