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 - 23.CBS34008 - Crank Bearing and Seal Kit - Fits Suzuki 2010-2011 RMX450Z, 2008-2024 RM-Z450
Prox
$156.95Prox - 09240347 - Crank Bearing and Seal Kit - SuzukiFeaturesIncludes all necessary bearings/seals for a component’s replacementFor use with OEM or Pro-X crankshafts.Specs$156.95 -
Prox - 23.CBS33003 - Crank Bearing and Seal Kit - Fits 2003-2004 Suzuki RM250
Prox
$80.95Prox - 09240336 - Crank Bearing and Seal Kit - SuzukiFeaturesIncludes all necessary bearings/seals for a component’s replacementFor use with OEM or Pro-X crankshafts.Specs$80.95 -
Prox - 23.CBS33007 - Crank Bearing and Seal Kit - Fits 2007-2009 Suzuki RM-Z250
Prox
$139.95Prox - 09240337 - Crank Bearing and Seal Kit - SuzukiFeaturesIncludes all necessary bearings/seals for a component’s replacementFor use with OEM or Pro-X crankshafts.Specs$139.95 -
Prox - 23.CBS33000 - Crank Bearing and Seal Kit - Fits 2000-2002 Suzuki RM250
Prox
$80.95Prox - 09240335 - Crank Bearing and Seal Kit - SuzukiFeaturesIncludes all necessary bearings/seals for a component’s replacementFor use with OEM or Pro-X crankshafts.Specs$80.95 -
Prox - 23.CBS32089 - Crank Bearing and Seal Kit - Fits 1989-1998 Suzuki RM125
Prox
$70.95Prox - 09240333 - Crank Bearing and Seal Kit - SuzukiFeaturesIncludes all necessary bearings/seals for a component’s replacementFor use with OEM or Pro-X crankshafts.Specs$70.95 -
Prox - 23.CBS31099 - Crank Bearing and Seal Kit - Fits Suzuki 1999-2001 RM80, 2002-2016 RM85
Prox
$52.95Prox - 09240331 - Crank Bearing and Seal Kit - SuzukiFeaturesIncludes all necessary bearings/seals for a component’s replacementFor use with OEM or Pro-X crankshafts.Specs$52.95 -
Prox - 23.CBS24098 - Crank Bearing Kit - Gas Gas/Yamaha - Yamaha YZ, WR & More
Prox
$102.95Prox - 09240329 - Crank Bearing Kit - Gas Gas/YamahaFeaturesIncludes all necessary bearings/seals for a component’s replacementFor use with OEM or Pro-X crankshafts.Specs$102.95 -
Prox - 23.CBS31089 - Crank Bearing and Seal Kit - Fits 1989-1998 Suzuki RM80
Prox
$49.95Prox - 09240330 - Crank Bearing and Seal Kit - SuzukiFeaturesIncludes all necessary bearings/seals for a component’s replacementFor use with OEM or Pro-X crankshafts.Specs$49.95 -
Prox - 23.CBS23088 - Crank Bearing and Seal Kit - Fits 1988-1997 Yamaha YZ250
Prox
$70.95Prox - 09240324 - Crank Bearing and Seal Kit - YamahaFeaturesIncludes all necessary bearings/seals for a component’s replacementFor use with OEM or Pro-X crankshafts.Specs$70.95 -
Prox - 23.CBS23099 - Crank Bearing and Seal Kit - Fits 1999-2000 Yamaha YZ250
Prox
$70.95Prox - 09240326 - Crank Bearing and Seal Kit - YamahaFeaturesIncludes all necessary bearings/seals for a component’s replacementFor use with OEM or Pro-X crankshafts.Specs$70.95 -
Prox - 23.CBS23083 - Crank Bearing and Seal Kit - Fits 1983-1987 Yamaha YZ250
Prox
$70.95Prox - 09240322 - Crank Bearing and Seal Kit - YamahaFeaturesIncludes all necessary bearings/seals for a component’s replacementFor use with OEM or Pro-X crankshafts.Specs$70.95 -
Prox - 01.3413.A - Piston Kit - 95.96 mm - Suzuki RMZ450 - Fits 2013-2024 Suzuki RM-Z450
Prox
$210.95Prox - 09102972 - Piston Kit - 95.96 mm - Suzuki RMZ450FeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$210.95 -
Prox - 01.4124.B - Piston Kit - 48.46 mm - Kawasaki KX85
Prox
$99.95Prox - 09103430 - Piston Kit - 48.46 mm - Kawasaki KX85FeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$99.95 -
Prox - 01.6029.C - Piston Kit - 44.98 mm - Gas Gas | Husqvarna | KTM
Prox
$77.95Prox - 09102484 - Piston Kit - 44.98 mm - Gas Gas | Husqvarna | KTMFeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely...$77.95 -
Prox - 01.4345.C - Piston Kit - 76.98 mm - Kawasaki KX250F
Prox
$179.95Prox - 09103906 - Piston Kit - 76.98 mm - Kawasaki KX250FFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$179.95 -
Prox - 01.6029.B - Piston Kit - 44.97 mm - Gas Gas | Husqvarna | KTM - Fits 2009-2024 KTM 65 SX
Prox
$77.95Prox - 09102483 - Piston Kit - 44.97 mm - Gas Gas | Husqvarna | KTMFeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely...$77.95 -
Prox - 01.6226.A - Piston Kit - 53.94 mm - Beta | Gas Gas | Husaberg | Husqvarna | KTM - Multiple Husqvarna/KTM Models
Prox
$143.95Prox - 09104546 - Piston Kit - 53.94 mm - Beta | Gas Gas | Husaberg | Husqvarna | KTMFeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then...$143.95 -
Prox - 01.4342.A - Piston Kit - 76.96 mm - Kawasaki KX250F - Fits 2011-2014 Kawasaki KX250F
Prox
$188.95Prox - 09104542 - Piston Kit - 76.96 mm - Kawasaki KX250FFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$188.95 -
Prox - 01.6019.C - Piston Kit - 39.48 mm - Gas Gas | Husqvarna | KTM
Prox
$77.95Prox - 09103271 - Piston Kit - 39.48 mm - Gas Gas | Husqvarna | KTMFeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely...$77.95 -
Prox - 01.4124.C - Piston Kit - 48.47 mm - Kawasaki KX85
Prox
$99.95Prox - 09103431 - Piston Kit - 48.47 mm - Kawasaki KX85FeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$99.95 -
Prox - 01.6019.B - Piston Kit - 39.47 mm - Gas Gas | Husqvarna | KTM - Fits 2009-2020 KTM 50 SX
Prox
$77.95Prox - 09103270 - Piston Kit - 39.47 mm - Gas Gas | Husqvarna | KTMFeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely...$77.95 -
Prox - 01.4124.A - Piston Kit - 48.45 mm - Kawasaki KX85 - Fits 2014-2024 Kawasaki KX85
Prox
$99.95Prox - 09103429 - Piston Kit - 48.45 mm - Kawasaki KX85FeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close...$99.95 -
Prox - 01.4413.B - Piston Kit - 95.98 mm - Kawasaki KX450F
Prox
$210.95Prox - 09103267 - Piston Kit - 95.98 mm - Kawasaki KX450FFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$210.95 -
Prox - 01.1232.B - Piston Kit - 65.98 mm - Honda CRF150R - Fits 2012-2024 Honda CRF150R
Prox
$177.95Prox - 09103252 - Piston Kit - 65.98 mm - Honda CRF150RFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$177.95 -
Prox - 02.6225 - Piston Rings - 54.00 mm - Beta | Husaberg | Husqvarna | KTM
Prox
$49.95Prox - 09120657 - Piston Rings - 54.00 mm - Beta | Husaberg | Husqvarna | KTMFeaturesHigh quality rings which allow for optimum heat transfer and sealingCan be used in cast iron bores, nickel ceramic...$49.95 -
Prox - 02.3337 - Piston Rings - 77.00 mm - Suzuki
Prox
$44.95Prox - 09120653 - Piston Rings - 77.00 mm - SuzukiFeaturesHigh quality rings which allow for optimum heat transfer and sealingCan be used in cast iron bores, nickel ceramic platings (Nikasil), boron...$44.95 -
Prox - 02.1227 - Piston Rings - 66.00 mm - Honda
Prox
$49.95Prox - 09120647 - Piston Rings - 66.00 mm - HondaFeaturesHigh quality rings which allow for optimum heat transfer and sealingCan be used in cast iron bores, nickel ceramic platings (Nikasil), boron...$49.95 -
Prox - 01.6226.B - Piston Kit - 53.95 mm - Beta | Gas Gas | Husaberg | Husqvarna | KTM
Prox
$143.95Prox - 09104547 - Piston Kit - 53.95 mm - Beta | Gas Gas | Husaberg | Husqvarna | KTMFeaturesCast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then...$143.95 -
Prox - 01.4342.B - Piston Kit - 76.97 mm - Kawasaki KX250F
Prox
$188.95Prox - 09104543 - Piston Kit - 76.97 mm - Kawasaki KX250FFeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$188.95 -
Prox - 01.3341.A - Piston Kit - 76.96 mm - Suzuki RMZ250 - Fits 2010-2024 Suzuki RM-Z250
Prox
$188.95Prox - 09104539 - Piston Kit - 76.96 mm - Suzuki RMZ250FeaturesPrecision machined on state of the art CNC equipmentMade with low expansion, low friction alloyReplacement Part for OEM...$188.95 -
Pro Circuit - PVK01085 - Power Valve - Kawasaki KX85 '02-'13
Pro Circuit
$229.95Pro Circuit - 09310477 - Power Valve - Kawasaki KX85 '02-'13FeaturesMaintain peak horsepower with huge gains in the bottom endConstructed of billet stainless steelMade in the USASpecs$229.95 -
Prox - 03.1227 - Connecting Rod Kit - Fits 2007-2013 Honda CRF150R
Prox
$131.95Prox - 09230237 - Connecting Rod Kit - HondaFeaturesEasy to installSpecsRiding StyleOff-Road<$131.95 -
Psr - 03-02000-29 - Cam Chain Tensioner - Honda - Fits 2007-2009 Honda CRF150R/RB, 2004-2017 Honda CRF250R/X, 2009-2023 Honda CRF450R, 2004-2009 Husqvarna TE 250-510
PSR
$74.95Psr - 09250786 - Cam Chain Tensioner - HondaFeaturesReplaces OEM automatic/hydraulic tensionerEliminates out-of-timing problems caused by the OEM automatic tensionerEliminates excess...$74.95 -
Prox - 01.6012.A - Piston Kit - 39.46 mm - KTM 50 Adventure/50SX - Fits 2001-2008 KTM 50 SX
Prox
$77.95Prox - 09106102 - Piston Kit - 39.46 mm - KTM 50 Adventure/50SXFeaturesOversized options follow manufacturer piston to cylinder wall clearancesKit includes piston, ring kit, wrist pin, and...$77.95 -
Prox - 01.6012.B - Piston Kit - 39.47 mm - KTM 50 Adventure/50SX
Prox
$77.95Prox - 09106103 - Piston Kit - 39.47 mm - KTM 50 Adventure/50SXFeaturesOversized options follow manufacturer piston to cylinder wall clearancesKit includes piston, ring kit, wrist pin, and...$77.95 -
Prox - 01.6220.A - Piston Kit - 53.94 mm - KTM 125SX - Fits 2001-2006 KTM 125 SX
Prox
$124.95Prox - 09106106 - Piston Kit - 53.94 mm - KTM 125SXFeaturesOversized options follow manufacturer piston to cylinder wall clearancesKit includes piston, ring kit, wrist pin, and circlipsSpecs$124.95 -
Psr - 03-02008-29 - Cam Chain Tensioner - Honda CRF & More
PSR
$74.95Psr - 09251258 - Cam Chain Tensioner - HondaFeaturesReplace OEM automatic/hydraulic tensionerRemove out-of-timing problems, premature engine wear and excess tension caused by an automatic...$74.95 -
Psr - 08-02000-28 - Cam Chain Tensioner - KTM
PSR
$74.95Psr - 09251260 - Cam Chain Tensioner - KTMFeaturesReplace OEM automatic/hydraulic tensionerRemove out-of-timing problems, premature engine wear and excess tension caused by an automatic...$74.95 -
Prox - 01.7411.A - Piston Kit - 94.95 mm - Beta 400RR - Fits 2010-2014 Beta 400 RR 4T
Prox
$216.95Prox - 09106808 - Piston Kit - 94.95 mm - Beta 400RRFeaturesThe piston is precision machined on state of the art CNC equipmentPiston rings are made by OEM factories to exact specificationsSpecs$216.95 -
Prox - 01.2448.A - Piston Kit - 96.95 mm - Yamaha WR450F/YZ450F/YZ450FX - Fits Yamaha 2019-2020 WR450F, 2018-2019 YZ450F, 2018-2020 YZ450FX, 2020-2022 YZ450F, 2021-2023 YZ450FX
Prox
$210.95Prox - 09106781 - Piston Kit - 96.95 mm - Yamaha WR450F/YZ450F/YZ450FXFeaturesThe piston is precision machined on state of the art CNC equipmentPiston rings are made by OEM factories to exact...$210.95
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.