Dirt Bike Engine
4752 parts
Pistons, top-end kits, gaskets, cylinders, valves, bearings and seals from Vertex, ProX, Wossner, Athena, Cometic, WSM, Boyesen and Moose Offroad. Everything you need for a fresh top end, a full rebuild or a little more power. Shop all dirt bike parts.
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Prox - 28.SES6329-1 - Valve and Spring Kit - Exhaust - Husaberg | KTM
Prox
$155.95Prox - 09261430 - Valve and Spring Kit - Exhaust - Husaberg | KTMFeaturesSteel, nitrided valves for increased durability and less wear under extreme conditionsStronger valve springs deal with the...$155.95 -
Prox - 28.SIS2402-2 - Valve and Spring Kit - Intake - Gas Gas | Yamaha - Fits 2001-2013 Yamaha WR/YZ250F
Prox
$212.95Prox - 09261460 - Valve and Spring Kit - Intake - Gas Gas | YamahaFeaturesSteel, nitrided valves for increased durability and less wear under extreme conditionsStronger valve springs deal with the...$212.95 -
Prox - 28.SES4335-1 - Valve and Spring Kit - Exhaust - Kawasaki | Suzuki - Fits Kawasaki 2004-2006 KX250F, 2007-2008 KX250F, 2009-2010 KX250F, 2011-2016 KX250F
Prox
$155.95Prox - 09261457 - Valve and Spring Kit - Exhaust - Kawasaki | SuzukiFeaturesSteel, nitrided valves for increased durability and less wear under extreme conditionsStronger valve springs deal with the...$155.95 -
Prox - 28.SES3338-1 - Valve and Spring Kit - Exhaust - Suzuki
Prox
$155.95Prox - 09261456 - Valve and Spring Kit - Exhaust - SuzukiFeaturesSteel, nitrided valves for increased durability and less wear under extreme conditionsStronger valve springs deal with the extra...$155.95 -
Prox - 28.1323-2 - Intake Valve - Fits Honda 2003-2005 CRF150F, 2003-2019 CRF230F
Prox
$22.95Prox - 09260671 - Intake Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14721KBB900Specs$22.95 -
Prox - 28.SES2402-1 - Valve and Spring Kit - Exhaust - Gas Gas | Yamaha - Fits 2001-2013 Yamaha WR/YZ250F
Prox
$155.95Prox - 09261455 - Valve and Spring Kit - Exhaust - Gas Gas | YamahaFeaturesSteel, nitrided valves for increased durability and less wear under extreme conditionsStronger valve springs deal with the...$155.95 -
Prox - 28.SIS1336-2 - Valve and Spring Kit - Intake - Fits Honda 2004-2007 CRF250R, 2004-2009 CRF250X
Prox
$155.95Prox - 09261458 - Valve and Spring Kit - Intake - HondaFeaturesSteel, nitrided valves for increased durability and less wear under extreme conditionsStronger valve springs deal with the extra weight...$155.95 -
Prox - 28.SIS6329-2 - Valve and Spring Kit - Intake - Husaberg | KTM
Prox
$155.95Prox - 09261436 - Valve and Spring Kit - Intake - Husaberg | KTMFeaturesSteel, nitrided valves for increased durability and less wear under extreme conditionsStronger valve springs deal with the...$155.95 -
Prox - 28.SES6327-1 - Valve and Spring Kit - Exhaust - KTM
Prox
$155.95Prox - 09261429 - Valve and Spring Kit - Exhaust - KTMFeaturesSteel, nitrided valves for increased durability and less wear under extreme conditionsStronger valve springs deal with the extra weight...$155.95 -
Prox - 28.1070-1 - Exhaust Valve - Fits Honda 2004-2012 CRF70F, 1997-2003 XR70R
Prox
$25.95Prox - 09260664 - Exhaust Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14721GF6000Specs$25.95 -
Prox - 28.2200-2 - Intake Valve - Fits 2000-2007 Yamaha TT-R125
Prox
$17.95Prox - 09260679 - Intake Valve - YamahaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):5HP1211101Specs$17.95 -
Psr - 03-02006-29 - Cam Chain Tensioner - Fits Honda 2018-2024 CRF250R, 2019-2024 CRF250RX
PSR
$74.95Psr - 09251033 - Cam Chain Tensioner - HondaFeaturesReplaces OEM automatic/hydraulic tensionerEliminates out-of-timing problems caused by the OEM automatic tensionerEliminates excess...$74.95 -
Prox - 01.3122.A - Piston Kit - 47.94 mm - Suzuki RM85 - Fits 2002-2023 Suzuki RM85
Prox
$99.95Prox - 09100431 - Piston Kit - 47.94 mm - Suzuki RM85FeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$99.95 -
Prox - 28.6520-1 - Exhaust Valve - Beta | Husaberg | KTM | Polaris - Fits 2005-2009 Beta RR 400/450/525, 2004-2008 Husqvarna FE 450/550/650, 2004-2008 Husqvarna FS 650, 2000-2002 KTM 520 EXC/SX, 2003-2007 KTM 525 EXC/SX
Prox
$56.95Prox - 09260688 - Exhaust Valve - Beta | Husaberg | KTM | PolarisFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):59036031000Specs$56.95 -
Prox - 28.1340-1 - Exhaust Valve - Fits 2010-2015 Honda CRF250R
Prox
$46.95Prox - 09261419 - Exhaust Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14721KRNA40Specs$46.95 -
Prox - 28.1381-1 - Exhaust Valve - Fits 1981-2002 Honda XR200R
Prox
$30.95Prox - 09260675 - Exhaust Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14721437000Specs$30.95 -
Prox - 28.6520-2 - Intake Valve - Beta | Husaberg | KTM | Polaris - Fits 2005-2009 Beta RR 400/450/525, 2004-2008 Husqvarna FE 450/550/650, 2004-2008 Husqvarna FS 650, 2000-2002 KTM 520 EXC/SX, 2003-2007 KTM 525 EXC/SX
Prox
$35.95Prox - 09260689 - Intake Valve - Beta | Husaberg | KTM | PolarisFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):59036030000Specs$35.95 -
Prox - 28.1323-1 - Exhaust Valve - Fits Honda 2003-2005 CRF150F, 2003-2019 CRF230F
Prox
$30.95Prox - 09260670 - Exhaust Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14721KBB900Specs$30.95 -
Prox - 28.2200-1 - Exhaust Valve - Fits 2000-2007 Yamaha TT-R125
Prox
$25.95Prox - 09260678 - Exhaust Valve - YamahaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):5HP1212100Specs$25.95 -
Prox - 28.1356-2 - Intake Valve - Fits 1996-2004 Honda XR250R
Prox
$22.95Prox - 09260674 - Intake Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14711KCZ000Specs$22.95 -
Prox - 28.1356-1 - Exhaust Valve - Fits 1996-2004 Honda XR250R
Prox
$30.95Prox - 09260673 - Exhaust Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14711KCZ000Specs$30.95 -
Prox - 28.1227-2 - Intake Valve - Fits 2007-2024 Honda CRF150R
Prox
$22.95Prox - 09260669 - Intake Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14721KSE670Specs$22.95 -
Prox - 28.1227-1 - Exhaust Valve - Fits 2007-2024 Honda CRF150R
Prox
$30.95Prox - 09260668 - Exhaust Valve - HondaFeaturesConstructed to meet OEM specificationsAvailable in standard sizes onlyReplacement Part for OEM Number(s):14721KSE670Specs$30.95 -
Prox - 01.1075.100 - Piston Kit - 48.00 mm - Honda
Prox
$59.95Prox - 09100401 - Piston Kit - 48.00 mm - HondaFeaturesOversize piston options follow manufacturer piston to cylinder wall clearancesPrecision machined on state of the art CNC equipmentKit includes...$59.95 -
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):14721KRM840Specs$22.95 -
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 -
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 -
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 -
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 -
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 -
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 -
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 -
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):14711GN5913Specs$17.95
Dirt Bike Pistons, Top-End Kits and Engine Rebuild Parts
Every dirt bike engine needs a refresh eventually. Ride long enough and the piston wears, compression drops and the bike just doesn't pull like it used to. Staying on top of top-end maintenance keeps your bike making power and keeps a cheap rebuild from turning into an expensive one.
We carry pistons and complete top-end kits from Vertex, Wossner, ProX and Athena, full gasket sets from Cometic and Athena, plus valves, springs, cam chains, bearings, seals and crank kits for full rebuilds. Boyesen reed valves and engine covers add performance and protection on two-strokes and four-strokes alike.
While the engine is apart, refresh the rest: fresh air filters and carb parts from fuel and intake, oil filters and fluids from oils and chemicals, and repacking or a new pipe from dirt bike exhaust.
Engine parts are specific to make, model, year and sometimes bore size, so check fitment carefully before ordering. If you're not sure what your rebuild needs, send us your bike's details and we'll help put the parts list together.