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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Cometic - C7136 - Top End Gasket Kit - Suzuki
Cometic
$40.95Cometic - C7136 - Top End Gasket Kit - SuzukiFeaturesMLS head gaskets promote an even torque load across the gasket sealing surface, providing less bore distortion and better piston ring seal for...$40.95 -
Cometic - C7399 - Top End Gasket Kit - Yamaha
Cometic
MSRP: $38.95$37.95Cometic - C7399 - Top End Gasket Kit - YamahaFeaturesMLS head gaskets promote an even torque load across the gasket sealing surface, providing less bore distortion and better piston ring seal for...MSRP: $38.95$37.95 -
Cometic - C7020 - Top End Gasket Kit - 91 mm - Honda
Cometic
$51.95Cometic - C7020 - Top End Gasket Kit - 91 mm - HondaFeaturesMLS head gaskets promote an even torque load across the gasket sealing surface, providing less bore distortion and better piston ring seal...$51.95 -
Boyesen - SCG-41 - Ignition Cover Replacement Gasket - KTM
Boyesen
$5.95Boyesen - 09341285 - Ignition Cover Replacement Gasket - KTMFeaturesSeals properly, guarding inside of engine from dirt and water and outlasts stock coversBoyesen Factory Covers are cast from the...$5.95 -
Boyesen - SC-30M - Ignition Cover - Magnesium - Yamaha
Boyesen
$87.95Boyesen - 09401108 - Ignition Cover - Magnesium - YamahaFeaturesSeals properly, guarding inside of engine from dirt and water and outlasts stock coversBoyesen Factory Covers are cast from the highest...$87.95 -
Cylinder Works - 20009-K01 - Cylinder Kit - Standard Bore - 66.40 mm - Fits 1999-2024 Yamaha YZ250
Cylinder Works
$842.95Cylinder Works - 09310587 - Cylinder Kit - Standard Bore - 66.40 mm - YamahaFeaturesCylinder kit includes matched Vertex pistons to ensure longevity, performance and reduced engine noiseNickel...$842.95 -
Boyesen - CC-17AB - Clutch Cover - Black - Fits 2009-2020 Kawasaki KX250F
Boyesen
$95.95Boyesen - 09401116 - Clutch Cover - Black - KawasakiFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a perfect,...$95.95 -
Boyesen - CC-18M - Clutch Cover - Magnesium - Fits 2006-2015 Kawasaki KX450F
Boyesen
$95.95Boyesen - 09401120 - Clutch Cover - Magnesium - KawasakiFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a perfect,...$95.95 -
Boyesen - CC-18B - Clutch Cover - Black - Fits 2006-2015 Kawasaki KX450F
Boyesen
$95.95Boyesen - 09401119 - Clutch Cover - Black - KawasakiFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a perfect,...$95.95 -
Boyesen - SC-10DM - Ignition Cover - Magnesium - Kawasaki KX 65
Boyesen
$87.95Boyesen - 09401104 - Ignition Cover - Magnesium - Kawasaki KX 65FeaturesSeals properly, guarding inside of engine from dirt and water and outlasts stock coversBoyesen Factory Covers are cast from the...$87.95 -
Boyesen - CC-30B - Clutch Cover - Black - Fits Yamaha 2018-2025 YZ65, 2002-2025 YZ85
Boyesen
$95.95Boyesen - 09401124 - Clutch Cover - Black - YamahaFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a perfect,...$95.95 -
Boyesen - CC-26AB - Clutch Cover - Black - Fits Suzuki 2017-2019 RMX450Z, 2008-2024 RM-Z450
Boyesen
$95.95Boyesen - 09401122 - Clutch Cover - Black - SuzukiFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a perfect,...$95.95 -
Boyesen - SC10AM - Ignition Cover - Magnesium - Kawasaki/Suzuki
Boyesen
$87.95Boyesen - 09401106 - Ignition Cover - Magnesium - Kawasaki/SuzukiFeaturesSeals properly, guarding inside of engine from dirt and water and outlasts stock coversBoyesen Factory Covers are cast from...$87.95 -
Del West - DW450RIV09ND - Intake Valve - No Dish - Honda CRF450R '09-'16
Del West
$155.95Del West - 09262262 - Intake Valve - No Dish - Honda CRF450R '09-'16FeaturesTitanium aluminide valves are designed to meet the most exacting requirementsSpecs$155.95 -
Del West - DW-CRF450R-EV13 - Exhaust Valve - Honda CRF450R '13-'16 - Fits 2013-2016 Honda CRF450R
Del West
$155.95Del West - 09262231 - Exhaust Valve - Honda CRF450R '13-'16FeaturesTitanium aluminide valves are designed to meet the most exacting requirementsSpecs$155.95 -
Del West - DW-RMZ250-IV10 - Intake Valve - Suzuki RMZ250 '10-'15
Del West
$155.95Del West - 09262254 - Intake Valve - Suzuki RMZ250 '10-'15FeaturesTitanium aluminide valves are designed to meet the most exacting requirementsSpecs$155.95 -
Del West - DWCRF450REV13ND - Exhaust Valve - No Dish - Honda CRF450R '13-'16
Del West
$171.95Del West - 09262261 - Exhaust Valve - No Dish - Honda CRF450R '13-'16FeaturesTitanium aluminide valves are designed to meet the most exacting requirementsSpecs$171.95 -
Del West - CRF250RIV10NDHF - Intake Valves
Del West
$155.95Del West - 09262469 - Intake ValvesFeaturesNo compromise designHigh-flow design includes a 50 seat angle, no dish valve face and 5 mm stem diameter (intake and exhaust) for better flow, higher...$155.95 -
Cylinder Works - CW21013K01 - Cylinder Kit - Big Bore - 80.00 mm - Yamaha
Cylinder Works
$819.95Cylinder Works - 09311021 - Cylinder Kit - Big Bore - 80.00 mm - YamahaFeaturesCylinders have a nickel silicon carbide cylinder sleeveLook virtually identical to OEM cylindersKit includes cylinder,...$819.95 -
Cylinder Works - CW20014 - Cylinder - 97.00 mm - Fits Yamaha 2020-2022 YZ450F, 2021-2022 YZ450FX
Cylinder Works
$421.95Cylinder Works - 09311020 - Cylinder - 97.00 mm - YamahaFeaturesNickel silicon carbide-plated for long lifeMade in the U.S.A.Specs$421.95 -
Cylinder Works - CW50012 - Cylinder - 39.50 mm - Gas Gas | Husqvarna | KTM - Fits 2021-2023 Gas Gas MC 50, 2017-2023 Husqvarna TC 50, 2009 KTM 50 SX Pro Jr, 2011-2014 KTM 50 SXS
Cylinder Works
$434.95Cylinder Works - 09311022 - Cylinder - 39.50 mm - Gas Gas | Husqvarna | KTMFeaturesNickel silicon carbide-plated for long lifeMade in the U.S.A.Specs$434.95 -
Cylinder Works - CH3001-K01 - Cylinder Head Kit - Fits 2006-2008 Kawasaki KX250F
Cylinder Works
$723.40Cylinder Works - 09311018 - Cylinder Head Kit - KawasakiFeaturesInclude cam caps and cam cap boltsInclude C630 (nickel/aluminum/bronze) valve seats and guidesCompetition valve jobShortened valve...$723.40 -
Cylinder Works - 10008 - Cylinder - 96.00 mm - Fits 2005-2017 Honda CRF450X
Cylinder Works
$421.95Cylinder Works - 09311013 - Cylinder - 96.00 mm - HondaFeaturesNickel silicon carbide-plated for long lifeMade in the U.S.A.Replacement Part for OEM Number(s):12100MEY670Specs$421.95 -
Cylinder Works - 50005 - Cylinder - 45.00 mm - Gas Gas | Husqvarna | KTM - Fits 2021-2023 Gas Gas MC 65, 2009 KTM 65 XC, 2017-2023 Husqvarna TC 65
Cylinder Works
$631.95Cylinder Works - 09311015 - Cylinder - 45.00 mm - Gas Gas | Husqvarna | KTMFeaturesNickel silicon carbide-plated for long lifeMade in the U.S.A.Specs$631.95 -
Cylinder Works - CW20012K01 - Cylinder Kit - Standard Bore - 97.00 mm - Yamaha
Cylinder Works
$788.95Cylinder Works - 09310849 - Cylinder Kit - Standard Bore - 97.00 mm - YamahaFeaturesCylinder kit includes matched Vertex pistons to ensure longevity, performance and reduced engine noiseNickel...$788.95 -
Cylinder Works - CW20012 - Cylinder - 97.00 mm - Standard - Fits Yamaha 2018-2019 YZ450F, 2019-2020 YZ450FX
Cylinder Works
$461.95Cylinder Works - 09310848 - Cylinder - 97.00 mm - Standard - YamahaFeaturesNickel silicon carbide-plated for long lifeMade in the U.S.A.Specs$461.95 -
Cylinder Works - CW20012K01HC - Cylinder Kit - High Compression - 97.00 mm - Yamaha
Cylinder Works
$801.95Cylinder Works - 09310850 - Cylinder Kit - High Compression - 97.00 mm - YamahaFeaturesCylinder kit comes with matched Vertex pistons to ensure longevity, performance and reduced engine noiseKit...$801.95 -
Cylinder Works - CW11011K01 - Cylinder Kit - Big Bore - 82.00 mm - Honda
Cylinder Works
$787.95Cylinder Works - 09310847 - Cylinder Kit - Big Bore - 82.00 mm - HondaFeaturesCylinders have a nickel silicon carbide cylinder sleeveLook virtually identical to OEM cylindersKit includes cylinder,...$787.95 -
Cylinder Works - 10002-K02 - Cylinder Kit - Standard Bore - 96.00 mm - Fits 2007-2008 Honda CRF450R
Cylinder Works
$651.95Cylinder Works - 09310839 - Cylinder Kit - Standard Bore - 96.00 mm - HondaFeaturesCylinder kit includes matched Vertex pistons to ensure longevity, performance and reduced engine noiseNickel Silicon...$651.95 -
Cylinder Works - CW10011K01 - Cylinder Kit - Standard Bore - 79.00 mm - Fits Honda 2018-2019 CRF250R, 2019 CRF250RX
Cylinder Works
$622.95Cylinder Works - 09310845 - Cylinder Kit - Standard Bore - 79.00 mm - HondaFeaturesCylinder kit includes matched Vertex pistons to ensure longevity, performance and reduced engine noiseNickel Silicon...$622.95 -
Cylinder Works - CW10011K01HC - Cylinder Kit - High Compression - 79.00 mm - Honda
Cylinder Works
$664.95Cylinder Works - 09310846 - Cylinder Kit - High Compression - 79.00 mm - HondaFeaturesCylinder kit comes with matched Vertex pistons to ensure longevity, performance and reduced engine noiseKit...$664.95 -
Cylinder Works - 10002-K02HC - Cylinder Kit - High Compression - 96.00 mm - Honda
Cylinder Works
$690.95Cylinder Works - 09310841 - Cylinder Kit - High Compression - 96.00 mm - HondaFeaturesCylinder kit comes with matched Vertex pistons to ensure longevity, performance and reduced engine noiseKit...$690.95 -
Cylinder Works - CH2005-K01 - Cylinder Head - Standard Bore - Fits 2005-2021 Yamaha YZ125
Cylinder Works
$145.95Cylinder Works - 09300205 - Cylinder Head - Standard Bore - YamahaFeaturesCompetition valve jobShortened valve guides to accept higher lift camsUnshrouded combustion chamberBlended bowl seat to...$145.95 -
Cylinder Works - CW20013 - Cylinder - 77.00 mm - Yamaha
Cylinder Works
$413.65Cylinder Works - 09311117 - Cylinder - 77.00 mm - YamahaFeaturesNickel silicon carbide-plated for long lifeMade in the U.S.A.Specs$413.65 -
Cylinder Works - 20009 - Cylinder - 66.40 mm - Yahama
Cylinder Works
$645.95Cylinder Works - 09311078 - Cylinder - 66.40 mm - YahamaFeaturesNickel Silicon Carbide plated for long lifeMade in the U.S.A.Big bore cylinders do not require machine work.Specs$645.95 -
Cylinder Works - CW20013K01 - Cylinder Kit - Standard Bore - 77.00 mm - Yamaha
Cylinder Works
$657.95Cylinder Works - 09311118 - Cylinder Kit - Standard Bore - 77.00 mm - YamahaFeaturesCylinder kit includes matched Vertex pistons to ensure longevity, performance and reduced engine noiseNickel...$657.95 -
Cometic - C3784-EST - Top End Gasket Kit - 91 mm - KTM
Cometic
$74.95Cometic - 09347854 - Top End Gasket Kit - 91 mm - KTMFeaturesMLS head gaskets promote an even torque load across the gasket sealing surface, providing less bore distortion and better piston ring seal...$74.95 -
Cometic - C3409-EST - Top End Gasket Kit - 82 mm - Suzuki
Cometic
$69.95Cometic - 09347836 - Top End Gasket Kit - 82 mm - SuzukiFeaturesMLS head gaskets promote an even torque load across the gasket sealing surface, providing less bore distortion and better piston ring...$69.95 -
Cometic - C7737 - Top End Gasket Kit - 48 mm - Kawasaki/Suzuki
Cometic
$28.95Cometic - 09347867 - Top End Gasket Kit - 48 mm - Kawasaki/SuzukiFeaturesMLS head gaskets promote an even torque load across the gasket sealing surface, providing less bore distortion and better...$28.95 -
Cylinder Works - 21009-K01 - Cylinder Kit - Big Bore - 72.00 mm - Yamaha
Cylinder Works
$1,255.75Cylinder Works - 09311163 - Cylinder Kit - Big Bore - 72.00 mm - YamahaFeaturesCylinders have a nickel silicon carbide cylinder sleeveLook virtually identical to OEM cylindersKit includes cylinder,...$1,255.75
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.