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.
- Product
- Qty in Cart
- Quantity
- Price
- Subtotal
-
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 - 01.4022.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 -
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):1291129F00Specs$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):14711KCY670Specs$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):1291229F00Specs$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):14721KCY670Specs$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 Number(s):5BE1211200Specs$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 Number(s):14721MEB670Specs$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):14711MG3000Specs$35.95 -
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):14721MAN620Specs$56.95 -
Prox - 42.1402 - Crankshaft Oil Seal Kit - Fits Honda 2004-2005 CRF250R, 2004-2006 CRF250X, 2002-2005 CRF450R
Prox
$22.95Prox - 09350070 - Crankshaft Oil Seal Kit - HondaFeaturesAll seals necessary for complete crank rebuild includedSpecs$22.95 -
Pro Circuit - PC4008-0401 - Replacement O-Ring
Pro Circuit
$5.95Pro Circuit - 09350003 - Replacement O-RingFeaturesSpecsApplicationWater Pump$5.95 -
Prox - 42.2225 - Crankshaft Oil Seal Kit - Yamaha
Prox
$16.95Prox - 09350071 - Crankshaft Oil Seal Kit - YamahaFeaturesAll seals necessary for complete crank rebuild includedSpecs$16.95 -
Prox - 42.3219 - Crankshaft Oil Seal Kit - Suzuki
Prox
$25.95Prox - 094398 - Crankshaft Oil Seal Kit - SuzukiFeaturesAll seals necessary for complete crank rebuild includedSpecs$25.95 -
Prox - 42.4403 - Crankshaft Oil Seal Kit - Kawasaki
Prox
$9.95Prox - 094489 - Crankshaft Oil Seal Kit - KawasakiFeaturesAll seals necessary for complete crank rebuild includedSpecs$9.95 -
Prox - 42.2221 - Crankshaft Oil Seal Kit - Yamaha
Prox
$22.95Prox - 094290 - Crankshaft Oil Seal Kit - YamahaFeaturesAll seals necessary for complete crank rebuild includedSpecs$22.95 -
Prox - 42.2319 - Crankshaft Oil Seal Kit - Yamaha
Prox
$22.95Prox - 094288 - Crankshaft Oil Seal Kit - YamahaFeaturesAll seals necessary for complete crank rebuild includedSpecs$22.95 -
Prox - 42.2102 - Crankshaft Oil Seal Kit - Yamaha
Prox
$10.95Prox - 094280 - Crankshaft Oil Seal Kit - YamahaFeaturesAll seals necessary for complete crank rebuild includedSpecs$10.95 -
Prox - 42.1312 - Crankshaft Oil Seal Kit - Honda
Prox
$16.95Prox - 094187 - Crankshaft Oil Seal Kit - HondaFeaturesAll seals necessary for complete crank rebuild includedSpecs$16.95 -
Prox - 42.1103 - Crankshaft Oil Seal Kit - Honda
Prox
$10.95Prox - 094181 - Crankshaft Oil Seal Kit - HondaFeaturesAll seals necessary for complete crank rebuild includedSpecs$10.95 -
Prox - 03.1409 - Connecting Rod Kit - Fits 2009-2016 Honda CRF450R
Prox
$183.95Prox - 09230345 - Connecting Rod Kit - HondaFeaturesEasy to installSpecsFeaturesIncludes Thrust Washers$183.95 -
Prox - 03.6029 - Connecting Rod Kit - Gas Gas | Husqvarna | KTM - Fits 2009-2017 KTM 65 SX
Prox
$118.95Prox - 09230277 - Connecting Rod Kit - Gas Gas | Husqvarna | KTMFeaturesEasy to installSpecsUnitsEach$118.95 -
Prox - 42.6218 - Crankshaft Oil Seal Kit - Multiple Models
Prox
$16.95Prox - 09350322 - Crankshaft Oil Seal KitFeaturesAll seals necessary for complete crank rebuild includedSpecsUni$16.95 -
Prox - 42.1405 - Crankshaft Oil Seal Kit - Fits Honda 2006-2016 CRF450R, 2005-2016 CRF450X, 2006-2017 CRF250R, 2007-2016 CRF250X
Prox
$22.95Prox - 09350294 - Crankshaft Oil Seal Kit - HondaFeaturesAll seals necessary for complete crank rebuild includedSpecs$22.95 -
Prox - 42.6320 - Crankshaft Oil Seal Kit - Multiple Models
Prox
$22.95Prox - 09350323 - Crankshaft Oil Seal KitFeaturesAll seals necessary for complete crank rebuild includedSpecsRid$22.95 -
Prox - 42.6029 - Crankshaft Oil Seal Kit - Gas Gas/Husqvarna/KTM - Fits 2017-2023 Husqvarna TC 65, 2021-2023 Gas Gas MC 65, 2009-2024 KTM 65 SX
Prox
$22.95Prox - 09350320 - Crankshaft Oil Seal Kit - Gas Gas/Husqvarna/KTMFeaturesAll seals necessary for complete crank rebuild includedSpecs$22.95
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.