{"title":"Rotax Max Crankshaft, Piston \u0026 Counterbalance Parts","description":"","products":[{"product_id":"rotax-max-crankshaft-assembly","title":"1. 685096 Rotax Max Crankshaft Assembly","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Crankshaft Assembly\u003c\/strong\u003e (R.685096) is the complete OEM crankshaft for the Rotax 125 MAX EVO engine, supplied as a fully assembled unit including the crank pin, big-end needle bearing, and crank webs. The crankshaft is the primary rotating component of the engine, converting the reciprocating motion of the piston into rotational output through the clutch and drivetrain. The Rotax MAX EVO crankshaft is a pressed-together precision assembly — it must be replaced as a unit rather than rebuilt individually outside of an authorized Rotax service center.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e. For crankshaft rebuild using OEM internals, see the Crankshaft Repair Kit (R.685011). The crankshaft requires the main bearings (R.832583 ×2) and both crankshaft oil seals (R.230425, R.930675) for installation.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.685096\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIncludes:\u003c\/strong\u003e Complete crankshaft with crank pin, big-end bearing, and crank webs\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCMC Karting stocks the Rotax crankshaft assembly alongside the crankshaft repair kit, main bearings, and oil seals for a complete crankshaft service.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168084799709,"sku":"R.685096","price":686.49,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-balance-shaft","title":"3. 237948 Rotax Max Balance Shaft","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Balance Shaft\u003c\/strong\u003e (R.237948) is the OEM counter-rotating shaft that cancels primary engine vibration on all Rotax 125 MAX EVO engines. Driven by the Balance Gear 50T (R.234435) at crankshaft speed, the balance shaft carries an eccentric weight that produces an equal and opposite force to the piston's reciprocating mass, dramatically reducing engine vibration at racing RPM. A damaged or bent balance shaft causes severe engine vibration, accelerated bearing wear, and can ultimately damage the crankcase bearing bores if left unaddressed.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e. Requires the balance shaft bearings (from Ch. 1), Balance Gear 50T (R.234435 ×2), and O-Ring 18x3.5 (R.430460) for installation.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.237948\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCMC Karting stocks the balance shaft alongside all drivetrain gears and the complete Rotax 125 MAX EVO engine rebuild parts.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168084832477,"sku":"R.237948","price":99.99,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-balance-shaft-o-ring-18x3-5","title":"7. 430460 Rotax Max Balance Shaft O-Ring 18x3.5","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Balance Shaft O-Ring 18x3.5\u003c\/strong\u003e (R.430460) is the OEM NBR 70 o-ring that seals the balance shaft bore in the Rotax 125 MAX EVO crankcase. This o-ring prevents gear oil from migrating through the balance shaft bore into the crankcase side, maintaining correct lubrication separation between the gearbox and crankcase chambers. A deteriorated or missing o-ring causes gear oil contamination of the crankcase and leads to lean running as oil enters the combustion mixture. Also included in the Engine Gasket Set (R.296160).\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e. Replace at every balance shaft or crankcase rebuild.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.430460\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecification:\u003c\/strong\u003e DIN 3771 – 18 x 3.5mm, NBR 70\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCMC Karting stocks this o-ring individually and as part of the Engine Gasket Set (R.296160).\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168084865245,"sku":"R.430460","price":4.55,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-balance-shaft-gear-50t","title":"8. 234435 Rotax Max Balance Shaft Gear 50 Tooth","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Balance Shaft Gear 50 Tooth\u003c\/strong\u003e (R.234435) is the OEM steel drive gear that connects the crankshaft to the balance shaft on all Rotax 125 MAX EVO engines. Two of these 50-tooth gears are used per engine — one mounted on the crankshaft and one on the balance shaft — meshing together to spin the balance shaft at precisely crankshaft speed in the opposite direction. Worn, chipped, or incorrectly meshed balance gears cause a characteristic gear whine at engine RPM and can lead to balance shaft misalignment and crankcase damage. Lubricate with Loctite Anti-Seize 15378 on installation.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.234435\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTeeth:\u003c\/strong\u003e 50T\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eQuantity Required:\u003c\/strong\u003e 2 per engine (one on crank, one on balance shaft)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eAlways replace balance gears in pairs. CMC Karting stocks them alongside the balance shaft and full drivetrain rebuild parts.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168084930781,"sku":"R.234435","price":92.91,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-water-pump-gear-19t","title":"9. 635850 Rotax Max Water Pump Gear 19 Tooth","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Water Pump Gear 19 Tooth\u003c\/strong\u003e (R.635850) is the OEM drive gear mounted on the balance shaft that transmits rotation to the water pump pinion gear (R.234415) on all Rotax 125 MAX EVO engines. This gear drives the water pump at a set ratio relative to engine RPM, ensuring adequate coolant circulation across the full RPM range. A worn or damaged water pump gear causes reduced pump speed, inadequate coolant flow at high RPM, and can ultimately lead to overheating under racing conditions.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e. Works with the 16-tooth pinion gear (R.234415) on the water pump shaft.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.635850\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTeeth:\u003c\/strong\u003e 19T\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCMC Karting stocks the water pump gear alongside the pinion gear and full Rotax drivetrain gear set.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168084963549,"sku":"R.635850","price":27.55,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-retaining-ring-20x1-2","title":"10. 945664 Rotax Max Retaining Ring 20x1.2","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Retaining Ring 20x1.2\u003c\/strong\u003e (R.945664) is the OEM DIN 983 external retaining ring used to secure gears and bearings on the balance shaft of the Rotax 125 MAX EVO engine. Two of these rings are used per engine, snapping into machined grooves in the shaft to prevent axial movement of the gears. A missing or deformed retaining ring allows gear walk on the balance shaft, causing tooth misalignment, accelerated gear wear, and potential gear-to-gear contact damage.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e. Single-use — always replace with a new ring at every gearbox rebuild.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.945664\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard:\u003c\/strong\u003e DIN 983, 20 x 1.2mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eQuantity Required:\u003c\/strong\u003e 2 per engine\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCMC Karting stocks retaining rings alongside the full Rotax 125 MAX EVO gearbox and balance shaft rebuild parts.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168085029085,"sku":"R.945664","price":1.62,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-balance-shaft-thrust-washer-10-1-17","title":"11. 827590 Rotax Max Balance Shaft Thrust Washer 10.1\/17\/1","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Balance Shaft Thrust Washer 10.1\/17\/1\u003c\/strong\u003e (R.827590) is the OEM axial location washer used on the balance shaft of the Rotax 125 MAX EVO gearbox. This washer controls the end-play of the balance shaft assembly within the crankcase, preventing excessive axial movement that would cause gear misalignment and tooth-edge contact. Correct balance shaft end-play is essential for quiet, efficient gear operation and long gear life.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.827590\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensions:\u003c\/strong\u003e 10.1mm inner \/ 17mm outer \/ 1mm thick\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCMC Karting stocks this thrust washer alongside all Rotax 125 MAX EVO balance shaft and gearbox components.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168085061853,"sku":"R.827590","price":2.88,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-gearbox-needle-pin-4x15-8","title":"12. 232732 Rotax Max Gearbox Needle Pin 4x15.8","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Gearbox Needle Pin 4x15.8\u003c\/strong\u003e (R.232732) is the OEM locating pin used in the Rotax 125 MAX EVO gearbox assembly to index the idle gear (R.634035) shaft position within the gear cover. This DIN 5402-3 precision needle pin ensures the idle gear shaft is correctly positioned for accurate gear mesh with the balance shaft and water pump drive gears. A missing or incorrectly fitted needle pin causes gear shaft migration, leading to misalignment and premature gear wear.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.232732\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard:\u003c\/strong\u003e DIN 5402-3 – 4 x 15.8mm, Grade G2\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCMC Karting stocks this needle pin alongside the idle gear and complete Rotax gearbox rebuild parts.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168085127389,"sku":"R.232732","price":2.12,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-water-pump-pinion-gear-16t","title":"13. 234415 Rotax Max Water Pump Pinion Gear 16 Tooth","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Water Pump Pinion Gear 16 Tooth\u003c\/strong\u003e (R.234415) is the OEM small drive gear mounted on the water pump shaft that meshes with the 19-tooth water pump gear (R.635850) on the balance shaft of all Rotax 125 MAX EVO engines. The 16T pinion and 19T drive gear together set the pump-to-engine speed ratio, determining coolant flow rate at any given engine RPM. A worn or chipped pinion gear causes noisy pump operation and reduced coolant flow efficiency.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e. Mounted on the water pump shaft assembly (R.220515).\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.234415\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTeeth:\u003c\/strong\u003e 16T\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCMC Karting stocks the water pump pinion alongside the 19T drive gear and the full Rotax gearbox gear set.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168085160157,"sku":"R.234415","price":25.94,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-idle-gear-28-13t","title":"15. 634035 Rotax Max Idle Gear 28\/13 Tooth","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Idle Gear 28\/13 Tooth\u003c\/strong\u003e (R.634035) is the OEM compound idle gear in the Rotax 125 MAX EVO gearbox. This dual-tooth gear — 28 teeth on the larger face and 13 teeth on the smaller — acts as an intermediate transfer gear between the balance shaft gear train and the e-starter reduction gear, also playing a role in the E-starter drive chain. A worn or damaged idle gear causes starting difficulties, gear noise at idle and low RPM, and can ultimately result in the e-starter reduction gear failing to disengage correctly after start.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e. Positioned in the gear cover using the gearbox needle pin (R.232732).\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.634035\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTeeth:\u003c\/strong\u003e 28T \/ 13T compound\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCMC Karting stocks the idle gear alongside the needle pin and the full Rotax 125 MAX EVO gearbox gear set.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168085225693,"sku":"R.634035","price":25.82,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-gear-cover-gasket","title":"16. 650476 Rotax Max Gear Cover Gasket","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Gear Cover Gasket\u003c\/strong\u003e (R.650476) is the OEM paper gasket that seals the joint between the crankcase and the gear cover (R.211875) on all Rotax 125 MAX EVO engines. This gasket maintains the oil-tight seal of the gearbox cavity, preventing gear oil from leaking out at the cover joint and ensuring the balance shaft, water pump drive gears, and idle gear remain correctly lubricated. Replace every time the gear cover is removed — a reused gasket will not provide a reliable seal. Also included in the Engine Gasket Set (R.296160).\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.650476\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLocation:\u003c\/strong\u003e Crankcase to gear cover joint\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCMC Karting stocks the gear cover gasket individually and as part of the full Engine Gasket Set (R.296160).\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168085258461,"sku":"R.650476","price":16.17,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-gear-cover","title":"17. 211875 Rotax Max Gear Cover","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Gear Cover\u003c\/strong\u003e (R.211875) is the OEM black-coated aluminum side cover that encloses the gearbox cavity — housing the balance shaft, water pump drive gears, idle gear, and e-starter reduction gear — on all Rotax 125 MAX EVO engines. The gear cover seals the gear oil lubricating the drivetrain gears and provides the mounting surface for the water pump shaft (R.220515) outer bearing location. A cracked or stripped gear cover requires replacement to maintain gear oil containment and correct gear shaft alignment.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e. Sealed with the Gear Cover Gasket (R.650476) and secured with six M6x25 Allen Bolts (R.840866) and two M6x30 Allen Bolts (R.840888), all tightened to 10 Nm.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.211875\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFinish:\u003c\/strong\u003e Black coated aluminum\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCMC Karting stocks the gear cover alongside the gear cover gasket and all gearbox internal components for a complete gearbox rebuild.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168085291229,"sku":"R.211875","price":89.04,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-gear-cover-sealing-ring-6x10","title":"18. 230415 Rotax Max Gear Cover Sealing Ring 6x10","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Gear Cover Sealing Ring 6x10 DIN 7603\u003c\/strong\u003e (R.230415) is the OEM soft aluminum crush washer used under the gear cover oil fill or drain plug on all Rotax 125 MAX EVO engines. This sealing ring deforms slightly under torque to provide a leak-free seal at the plug, preventing gear oil weeping from the drain point. Unlike rubber o-rings, this crush washer is a single-use item — it must be replaced every time the plug is removed to ensure a reliable seal on reassembly.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.230415\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard:\u003c\/strong\u003e DIN 7603, 6 x 10mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e Soft aluminum crush washer (single-use)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eAlways fit a new sealing ring when reinstalling the gear cover drain plug — they are inexpensive and available from CMC Karting alongside the full Rotax gearbox parts line.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168085356765,"sku":"R.230415","price":1.76,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-wrist-pin-needle-cage-bearing","title":"21. 932027 Rotax Max Wrist Pin Needle Cage Bearing 15x19x20","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Wrist Pin Needle Cage Bearing 15x19x20\u003c\/strong\u003e (R.932027) is the OEM needle roller bearing that supports the connecting rod on the piston wrist pin of all Rotax 125 MAX EVO engines. This bearing sits inside the small end of the connecting rod, allowing the rod to pivot on the wrist pin (R.216135) as the piston reciprocates. The wrist pin bearing is a high-load, high-cycle component — wear or failure results in piston slap, a distinctive tapping noise, and can lead to catastrophic piston and cylinder damage if not replaced promptly. Replace at every piston change or major engine rebuild.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e. Used with the Piston Assembly (R.295509–R.295515) and Wrist Pin (R.216135).\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.932027\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensions:\u003c\/strong\u003e 15 x 19 x 20mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eAlways replace the wrist pin needle bearing when installing a new piston. CMC Karting stocks it alongside the piston assemblies and wrist pin for a complete top-end rebuild kit.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168085389533,"sku":"R.932027","price":45.49,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-piston-assembly","title":"22. Rotax Max Piston Assembly 53.92mm to 53.98mm","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Piston Assembly\u003c\/strong\u003e is the complete OEM piston for the Rotax 125 MAX EVO engine, supplied with the piston pin, wrist pin circlips (R.945635), and piston ring pre-installed. Available in seven diameter grades from \u003cstrong\u003e53.92mm to 53.98mm\u003c\/strong\u003e in 0.01mm increments, allowing precise cylinder-to-piston clearance matching during engine rebuild. The correct piston size is determined by measuring the cylinder bore and selecting the piston that achieves the Rotax-specified running clearance — using the wrong size piston risks seizure (too tight) or excessive blow-by and power loss (too loose).\u003c\/p\u003e\n\u003cp\u003eSizes 53.92mm and 53.93mm are the smaller-spec pistons; 53.94mm–53.96mm are standard grade; 53.97mm and 53.98mm are oversize. Compatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e. Requires the Wrist Pin Needle Cage Bearing (R.932027) and Wrist Pin (R.216135), sold separately.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Numbers:\u003c\/strong\u003e R.295509 (53.92mm) through R.295515 (53.98mm)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIncludes:\u003c\/strong\u003e Piston, piston pin, piston ring, and 2 circlips\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eMeasure your cylinder before ordering. CMC Karting stocks all seven piston grades alongside the wrist pin bearing and complete Rotax 125 MAX EVO top-end rebuild parts.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"53.92mm – Smaller (R.295509)","offer_id":48168085455069,"sku":"R.295509","price":144.69,"currency_code":"USD","in_stock":true},{"title":"53.93mm – Smaller (R.295510)","offer_id":48168085487837,"sku":"R.295510","price":144.69,"currency_code":"USD","in_stock":true},{"title":"53.94mm – Standard (R.295511)","offer_id":48168085520605,"sku":"R.295511","price":144.69,"currency_code":"USD","in_stock":true},{"title":"53.95mm – Standard (R.295512)","offer_id":48168085553373,"sku":"R.295512","price":144.69,"currency_code":"USD","in_stock":true},{"title":"53.96mm – Standard (R.295513)","offer_id":48168085586141,"sku":"R.295513","price":144.69,"currency_code":"USD","in_stock":true},{"title":"53.97mm – Oversize (R.295514)","offer_id":48168085618909,"sku":"R.295514","price":144.69,"currency_code":"USD","in_stock":true},{"title":"53.98mm – Oversize (R.295515)","offer_id":48168085651677,"sku":"R.295515","price":144.69,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-wrist-pin-15x45-6","title":"24. 216135 Rotax Max Wrist Pin 15x45.6mm","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Wrist Pin 15x45.6mm\u003c\/strong\u003e (R.216135) is the OEM hardened steel wrist pin (also known as the gudgeon pin or piston pin) that connects the piston to the connecting rod on all Rotax 125 MAX EVO engines. The wrist pin passes through the piston bosses and through the wrist pin needle cage bearing (R.932027) in the connecting rod small end, providing the articulation point for the piston-rod assembly. A scored, worn, or out-of-round wrist pin causes bearing wear, piston boss damage, and the characteristic piston slap noise that indicates imminent top-end failure. Replace at every piston change.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e. Retained by two Circlips 15 (R.945635).\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.216135\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensions:\u003c\/strong\u003e 15mm diameter x 45.6mm length\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCMC Karting stocks the wrist pin alongside circlips, the needle cage bearing, and all piston assembly sizes for a complete Rotax top-end rebuild.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168085782749,"sku":"R.216135","price":29.38,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-wrist-pin-circlip-15mm","title":"25. 945635 Rotax Max Wrist Pin Circlip 15mm","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Wrist Pin Circlip 15mm\u003c\/strong\u003e (R.945635) is the OEM external circlip that retains the wrist pin (R.216135) within the piston boss on all Rotax 125 MAX EVO engines. Two circlips are used per piston — one on each side of the wrist pin — snapping into machined grooves in the piston boss to prevent the wrist pin from migrating laterally and contacting the cylinder wall. A deformed, fatigued, or incorrectly seated circlip that lets go at engine RPM causes catastrophic cylinder and piston damage. Always use new circlips at every piston installation — they are single-use items. Also included in the Piston Assembly (R.295509–R.295515) and Engine Gasket Set (R.296160).\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.945635\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSize:\u003c\/strong\u003e 15mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eQuantity Required:\u003c\/strong\u003e 2 per piston (sold individually)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eAlways fit new circlips — never reuse them. CMC Karting stocks these alongside piston assemblies and wrist pins for complete Rotax top-end rebuilds.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168085848285,"sku":"R.945635","price":2.07,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-crankshaft-repair-kit","title":"26. 685011 Rotax Max Crankshaft Repair Kit","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Crankshaft Repair Kit\u003c\/strong\u003e (R.685011) is the OEM crankshaft rebuild kit for the Rotax 125 MAX EVO engine, containing the big-end needle bearing, big-end pin, thrust washers, and all associated hardware needed to rebuild the crankshaft assembly to factory specification. This kit is the alternative to full crankshaft replacement (R.685096) when the crankshaft crank webs and lower end are still in serviceable condition but the big-end bearing and pin require replacement. Crankshaft rebuilding must be performed with the correct pressing equipment to achieve correct crank web alignment — this kit is intended for use by authorized Rotax service centers or experienced engine builders with the appropriate tooling.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.685011\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIncludes:\u003c\/strong\u003e Big-end needle bearing, crank pin, thrust washers, and assembly hardware\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCMC Karting stocks the crankshaft repair kit alongside the complete crankshaft assembly for all Rotax 125 MAX EVO rebuild scenarios.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168085881053,"sku":"R.685011","price":361.78,"currency_code":"USD","in_stock":true}]},{"product_id":"rotax-max-piston-ring-rectangular","title":"215548 Rotax Max Piston Ring – Rectangular","description":"\u003cp\u003eThe \u003cstrong\u003eRotax Max Piston Ring Rectangular\u003c\/strong\u003e (R.215548) is the OEM replacement piston ring for the Rotax 125 MAX EVO engine. The Rotax MAX EVO uses a single rectangular compression ring seated in the piston ring groove. This ring forms the primary gas seal between the piston and cylinder wall — maintaining the compression and combustion pressure that drives piston movement. A worn or broken piston ring causes loss of compression, blow-by into the crankcase, increased oil consumption from the gear side, and a characteristic white smoke from burned gear oil. Replace at every piston change or any time compression testing reveals a piston ring sealing issue.\u003c\/p\u003e\n\u003cp\u003eCompatible with all Rotax 125 MAX EVO variants: \u003cstrong\u003eRotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/strong\u003e. The piston ring is pre-installed in the Piston Assembly (R.295509–R.295515) but is also available separately for use with an existing serviceable piston.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Part Number:\u003c\/strong\u003e R.215548\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e Rectangular compression ring\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpecification:\u003c\/strong\u003e IS2 – 54\/49.4 x 1mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Rotax 125 Senior MAX EVO, Junior MAX EVO, Mini MAX EVO, Micro MAX EVO\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCMC Karting stocks the piston ring alongside piston assemblies, wrist pins, circlips, and the full Rotax 125 MAX EVO top-end rebuild parts.\u003c\/p\u003e","brand":"KSG\/Karting Solutions Group","offers":[{"title":"Default Title","offer_id":48168085946589,"sku":"R.215548","price":81.49,"currency_code":"USD","in_stock":true}]}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0731\/6770\/0189\/collections\/CMC_Rotax_Max_Crankshaft_Piston_Counterbalance_Parts.png?v=1779734986","url":"https:\/\/cmckarting.com\/collections\/rotax-max-crankshaft-piston-counterbalance-parts.oembed?page=2","provider":"CMC Karting","version":"1.0","type":"link"}