Prox
ProX is a globally recognized brand specializing in motorcycle engine components and rebuild kits, including pistons, gasket kits, crankshafts and clutch parts. Designed for motocross, dirt bikes and off-road machines, ProX delivers OEM-quality precision and durability. Their lineup also includes wheel spacer kits, valve kits and bearing solutions for complete engine and chassis maintenance. Riders trust ProX for high-performance engine rebuild parts and reliable aftermarket components.
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Prox - 01.2225.C - Piston Kit - 53.97 mm - Yamaha YZ125/YZ125X
Prox
$121.95Prox - 09100596 - Piston Kit - 53.97 mm - Yamaha YZ125/YZ125XFeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$121.95 -
Prox - 28.1226-2 - Intake Valve - Fits 2006-2017 Honda CRF150F
Prox
$22.95Prox - 09260667 - Intake Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14721KRM840SpecsMaterialSteelRiding...$22.95 -
Out of stock
Prox - 01.1225.A - Piston Kit - 53.94 mm - Honda CR125R - Fits 2005-2006 Honda CR125R
Prox
$105.95Prox - 09100597 - Piston Kit - 53.94 mm - Honda CR125RFeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$105.95 -
Prox - 01.4335.B - Piston Kit - 76.97 mm - Kawasaki KX250F | Suzuki RMZ250
Prox
$188.95Prox - 09100426 - Piston Kit - 76.97 mm - Kawasaki KX250F | Suzuki RMZ250FeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for...$188.95 -
Out of stock
Prox - 01.1403.B - Piston Kit - 95.97 mm - Honda CRF450R
Prox
$195.95Prox - 09100419 - Piston Kit - 95.97 mm - Honda CRF450RFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$195.95 -
Out of stock
Prox - 01.1225.C - Piston Kit - 53.96 mm - Honda CR125R
Prox
$105.95Prox - 09100599 - Piston Kit - 53.96 mm - Honda CR125RFeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$105.95 -
Out of stock
Prox - 01.4223.B - Piston Kit - 53.96 mm - Kawasaki KX125
Prox
$105.95Prox - 09100025 - Piston Kit - 53.96 mm - Kawasaki KX125FeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$105.95 -
Prox - 01.2429.B - Piston Kit - 94.96 mm - Gas Gas | Yamaha
Prox
$210.95Prox - 09100440 - Piston Kit - 94.96 mm - Gas Gas | YamahaFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$210.95 -
Out of stock
Prox - 01.2406.A - Piston Kit - 76.95 mm - Gas Gas | Yamaha - Fits Yamaha 2001-2013 WR250F, 2001-2007 YZ250F
Prox
$179.95Prox - 09100027 - Piston Kit - 76.95 mm - Gas Gas | YamahaFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$179.95 -
Prox - 01.1075.000 - Piston Kit - 47.00 mm - Fits Honda 2004-2012 CRF70F, 1997-2003 XR70R
Prox
$77.95Prox - 09100399 - Piston Kit - 47.00 mm - HondaFeaturesOversize piston options follow manufacturer piston to cylinder wall clearancesPrecision machined on state of the art CNC equipmentKit includes...$77.95 -
Prox - 01.1113.C - Piston Kit - 47.46 mm - Honda CR85R
Prox
$99.95Prox - 09100021 - Piston Kit - 47.46 mm - Honda CR85RFeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$99.95 -
Prox - 01.1113.B - Piston Kit - 47.45 mm - Honda CR85R - Fits 2003-2007 Honda CR85
Prox
$99.95Prox - 09100020 - Piston Kit - 47.45 mm - Honda CR85RFeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$99.95 -
Prox - 01.2429.C - Piston Kit - 94.97 mm - Gas Gas | Yamaha
Prox
$195.95Prox - 09030829 - Piston Kit - 94.97 mm - Gas Gas | YamahaFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$195.95 -
Prox - 01.4022.A - Piston Kit - 44.45 mm - Kawasaki KX65 | Suzuki RM65 - Fits 2000-2024 Kawasaki KX65, 2000-2003 Suzuki RM65
Prox
$88.95Prox - 09100022 - Piston Kit - 44.45 mm - Kawasaki KX65 | Suzuki RM65FeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely...$88.95 -
Out of stock
Prox - 01.4325.C - Piston Kit - 66.36 mm - Kawasaki KX250
Prox
$139.95Prox - 09100601 - Piston Kit - 66.36 mm - Kawasaki KX250FeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$139.95 -
Out of stock
Prox - 01.4325.B - Piston Kit - 66.35 mm - Kawasaki KX250 - Fits 2005-2008 Kawasaki KX250
Prox
$139.95Prox - 09100600 - Piston Kit - 66.35 mm - Kawasaki KX250FeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$139.95 -
Prox - 01.1414.B - Piston Kit - 95.97 mm - Honda CRF450R/CRF450X
Prox
$210.95Prox - 09100608 - Piston Kit - 95.97 mm - Honda CRF450R/CRF450XFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$210.95 -
Out of stock
Prox - 01.1411.B - Piston Kit - 95.97 mm - Honda - CRF450R - Fits 2009-2012 Honda CRF450R
Prox
$195.95Prox - 09030823 - Piston Kit - 95.97 mm - Honda - CRF450RFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$195.95 -
Out of stock
Prox - 01.3224.A - Piston Kit - 53.95 mm - Suzuki RM125 - Fits 2004-2011 Suzuki RM125
Prox
$105.95Prox - 09100434 - Piston Kit - 53.95 mm - Suzuki RM125FeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$105.95 -
Out of stock
Prox - 01.3122.C - Piston Kit - 47.96 mm - Suzuki RM85
Prox
$94.95Prox - 09100433 - Piston Kit - 47.96 mm - Suzuki RM85FeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$94.95 -
Prox - 01.2429.A - Piston Kit - 94.95 mm - Gas Gas | Yamaha - Fits Yamaha 2003-2011 WR450F, 2003-2009 YZ450F
Prox
$210.95Prox - 09100439 - Piston Kit - 94.95 mm - Gas Gas | YamahaFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$210.95 -
Prox - 01.1222.A - Piston Kit - 53.94 mm - Honda CR125R - Fits 2004 Honda CR125R
Prox
$132.95Prox - 09100428 - Piston Kit - 53.94 mm - Honda CR125RFeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$132.95 -
Out of stock
Prox - 01.4223.C - Piston Kit - 53.97 mm - Kawasaki KX125
Prox
$101.95Prox - 09100026 - Piston Kit - 53.97 mm - Kawasaki KX125FeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$101.95 -
Out of stock
Prox - 01.1403.A - Piston Kit - 95.96 mm - Honda CRF450R - Fits 2002-2003 Honda CRF450R
Prox
$195.95Prox - 09100418 - Piston Kit - 95.96 mm - Honda CRF450RFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$195.95 -
Prox - 01.2406.B - Piston Kit - 76.96 mm - Gas Gas | Yamaha
Prox
$188.95Prox - 09100028 - Piston Kit - 76.96 mm - Gas Gas | YamahaFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$188.95 -
Out of stock
Prox - 01.4335.A - Piston Kit - 76.96 mm - Kawasaki KX250F | Suzuki RMZ250 - Fits 2004-2005 Kawasaki KX250F, 2004-2006 Suzuki RM-Z250
Prox
$179.95Prox - 09100425 - Piston Kit - 76.96 mm - Kawasaki KX250F | Suzuki RMZ250FeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for...$179.95 -
Prox - 01.4022.B - Piston Kit - 44.46 mm - Kawasaki KX65 | Suzuki RM65
Prox
$88.95Prox - 09100023 - Piston Kit - 44.46 mm - Kawasaki KX65 | Suzuki RM65FeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely...$88.95 -
Out of stock
Prox - 01.1342.B - Piston Kit - 76.78 mm - Honda CRF250R
Prox
$185.95Prox - 09030816 - Piston Kit - 76.78 mm - Honda CRF250RFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$185.95 -
Prox - 01.1408.150 - Piston Kit - 90.50 mm - Honda CR500R
Prox
$185.95Prox - 09030820 - Piston Kit - 90.50 mm - Honda CR500RFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyKit includes piston, rings, circlips and...$185.95 -
Prox - 28.1070-2 - Intake Valve - Fits Honda 2004-2012 CRF70F, 1997-2003 XR70R
Prox
$17.95Prox - 09260665 - Intake Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14711GN5913SpecsRiding...$17.95 -
Prox - 28.1226-1 - Exhaust Valve - Fits 2006-2017 Honda CRF150F
Prox
$30.95Prox - 09260666 - Exhaust Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14721KRM840SpecsRiding...$30.95 -
Prox - 28.3402-2 - Intake Valve - Kawasaki | Suzuki - Fits 2003 Kawasaki KLX400, 2000-2009 Suzuki DR-Z400
Prox
$30.95Prox - 09260151 - Intake Valve - Kawasaki | SuzukiFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):1291129F00SpecsMaterialSteelRiding...$30.95 -
Prox - 28.1495-2 - Intake Valve - Fits 1996-2005 Honda XR400R
Prox
$25.95Prox - 09260149 - Intake Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14711KCY670SpecsRiding StyleAdventure Touring /...$25.95 -
Prox - 28.3402-1 - Exhaust Valve - Kawasaki | Suzuki - Fits 2003 Kawasaki KLX400, 2000-2009 Suzuki DR-Z400
Prox
$35.95Prox - 09260147 - Exhaust Valve - Kawasaki | SuzukiFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):1291229F00SpecsMaterialSteelRiding...$35.95 -
Prox - 28.1495-1 - Exhaust Valve - Fits 1996-2005 Honda XR400R
Prox
$35.95Prox - 09260145 - Exhaust Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14721KCY670SpecsProduct...$35.95 -
Prox - 28.2418-3 - Intake Valve - Fits Yamaha 1998-2000 WR/YZ400F, 2000 YZ426F
Prox
$22.95Prox - 09260153 - Intake Valve - YamahaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM...$22.95 -
Prox - 28.1402-1 - Exhaust Valve - Fits 2002-2006 Honda CRF450R
Prox
$40.95Prox - 09260144 - Exhaust Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM...$40.95 -
Prox - 28.1654-2 - Intake Valve - Fits Honda 1993-2000 XR600R, 1988-1996 NX650, 1993-2023 XR650L
Prox
$35.95Prox - 09260150 - Intake Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14711MG3000SpecsProduct...$35.95 -
Out of stock
Prox - 28.2418-1 - Exhaust Valve - Fits Yamaha 1998-2000 WR/YZ400F, 2000 YZ426F
Prox
$29.95Prox - 09260148 - Exhaust Valve - YamahaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):5BE1212100SpecsMaterialSteelRiding...$29.95 -
Prox - 28.1654-1 - Exhaust Valve - Fits Honda 1993-2000 XR600R, 1988-1996 NX650, 1993-2023 XR650L
Prox
$56.95Prox - 09260146 - Exhaust Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14721MAN620SpecsRiding...$56.95
ProX Racing Performance Engine Systems – Pistons, Crankshafts & Complete Rebuild Components
ProX is a leading manufacturer of high-performance motorcycle engine components, offering a comprehensive range of parts engineered to meet or exceed OEM specifications. Their extensive lineup includes piston kits, ring sets, connecting rod kits and crankshaft bearing kits designed for precision fitment and long-lasting durability. Built for motocross, enduro and off-road applications, ProX components are manufactured using advanced materials and strict quality control standards to ensure consistent performance under extreme riding conditions. These motorcycle engine rebuild parts are trusted by riders and mechanics worldwide for restoring power, improving reliability and maintaining peak engine efficiency.
Beyond internal engine components, ProX provides a wide selection of gasket kits, top end gasket sets and water pump rebuild kits that support complete engine overhauls and routine maintenance. Their gasket solutions are designed to deliver proper sealing and leak prevention across high-temperature engine environments, while water pump kits ensure optimal cooling system performance. In addition, ProX offers valve and spring kits, cam chains and valve shims, enabling precise engine tuning and valve train reliability. These components are essential for maintaining engine timing, compression and overall performance in demanding off-road and racing conditions.
ProX also supports chassis and braking system maintenance with products like wheel spacer kits, brake caliper rebuild kits and master cylinder rebuild kits, ensuring complete mechanical reliability beyond the engine. Their clutch components, including clutch plate sets and inner clutch hubs, are engineered to handle high torque loads while maintaining smooth engagement and durability. Whether performing a full engine rebuild or upgrading specific components, ProX delivers a complete solution for riders seeking motorcycle performance parts, engine rebuild kits and off-road racing components that enhance durability, precision and long-term performance.