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Dirt Bike Engine

3553 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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  • Out of stock
    Athena - P4C0540118014A - Piston Kit with Gaskets - 53.95 mm - Yamaha Athena - P4C0540118014A - Piston Kit with Gaskets - 53.95 mm - Yamaha

    Athena - P4C0540118014A - Piston Kit with Gaskets - 53.95 mm - Fits 2005-2021 Yamaha YZ125

    Athena

    $153.95
    Athena - 09031786 - Piston Kit with Gaskets - 53.95 mm - YamahaFeaturesThe smooth profile ensures a regular flow and the perfect flame propagationThe piston for 2-stroke Off-Road are produced by...
    $153.95
    Qty in Cart: 0
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    $153.95
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  • Out of stock
    Athena - P4C0445008001A - Piston Kit with Gaskets - 44.45 mm - Kawasaki Athena - P4C0445008001A - Piston Kit with Gaskets - 44.45 mm - Kawasaki

    Athena - P4C0445008001A - Piston Kit with Gaskets - 44.45 mm - Fits 2000-2023 Kawasaki KX65

    Athena

    $121.95
    Athena - 09031782 - Piston Kit with Gaskets - 44.45 mm - KawasakiFeaturesThe smooth profile ensures a regular flow and the perfect flame propagationThe piston for 2-stroke Off-Road are produced by...
    $121.95
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    $121.95
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  • Out of stock
    Athena - P4C0664083001A - Piston Kit with Gaskets - 66.34 mm - Gas Gas | Husqvarna | KTM Athena - P4C0664083001A - Piston Kit with Gaskets - 66.34 mm - Gas Gas | Husqvarna | KTM

    Athena - P4C0664083001A - Piston Kit with Gaskets - 66.34 mm - Gas Gas | Husqvarna | KTM - Fits 2017-2022 KTM 250 SX

    Athena

    $187.95
    Athena - 09031778 - Piston Kit with Gaskets - 66.34 mm - Gas Gas | Husqvarna | KTMFeaturesThe smooth profile ensures a regular flow and the perfect flame propagationThe piston for 2-stroke Off-Road...
    $187.95
    Qty in Cart: 0
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    $187.95
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  • Out of stock
    Athena - P4C0720045002A - Piston Kit with Gaskets - 71.93 mm - KTM Athena - P4C0720045002A - Piston Kit with Gaskets - 71.93 mm - KTM

    Athena - P4C0720045002A - Piston Kit with Gaskets - 71.93 mm - Fits 2013-2016 KTM 300 XC-W/EXC

    Athena

    $231.95
    Athena - 09031776 - Piston Kit with Gaskets - 71.93 mm - KTMFeaturesThe smooth profile ensures a regular flow and the perfect flame propagationThe piston for 2-stroke Off-Road are produced by...
    $231.95
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    $231.95
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  • Out of stock
    Athena - P4C0720083002B - Piston Kit with Gaskets - 71.94 mm - Gas Gas | Husqvarna | KTM Athena - P4C0720083002B - Piston Kit with Gaskets - 71.94 mm - Gas Gas | Husqvarna | KTM

    Athena - P4C0720083002B - Piston Kit with Gaskets - 71.94 mm - Gas Gas | Husqvarna | KTM

    Athena

    $231.95
    Athena - 09031775 - Piston Kit with Gaskets - 71.94 mm - Gas Gas | Husqvarna | KTMFeaturesThe smooth profile ensures a regular flow and the perfect flame propagationThe piston for 2-stroke Off-Road...
    $231.95
    Qty in Cart: 0
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    $231.95
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  • Out of stock
    Athena - S5F05300001A - Piston Kit - 52.95 mm - Yamaha Athena - S5F05300001A - Piston Kit - 52.95 mm - Yamaha

    Athena - S5F05300001A - Piston Kit - 52.95 mm - Fits 2002-2025 Yamaha YZ85

    Athena

    $229.95
    Athena - 09106894 - Piston Kit - 52.95 mm - YamahaFeaturesBoth include 3% copper in materials for better heat resistanceAll pistons are forged using a precision heat-treatment process that allows for...
    $229.95
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    $229.95
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  • Out of stock
    Athena - P400485600004 - Top End Gasket Kit - Yamaha Athena - P400485600004 - Top End Gasket Kit - Yamaha

    Athena - P400485600004 - Top End Gasket Kit - Fits 1982-2016 Yamaha PW50

    Athena

    $13.95
    Athena - 09344818 - Top End Gasket Kit - YamahaFeaturesKit includes a top-of-the line MLSS head gasket and two or more premium quality base gaskets of different thicknesses to optimize engine...
    $13.95
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    $13.95
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  • Out of stock
    Boyesen - SC12B - Ignition Cover - Black - Kawasaki KX250 Boyesen - SC12B - Ignition Cover - Black - Kawasaki KX250

    Boyesen - SC12B - Ignition Cover - Black - Kawasaki KX250

    Boyesen

    $87.95
    Boyesen - SC12B - Ignition Cover - Black - Kawasaki KX250FeaturesSeals properly, guarding inside of engine from dirt and water and outlasts stock coversBoyesen Factory Covers are cast from the...
    $87.95
    Qty in Cart: 0
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    $87.95
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  • Out of stock
    Boyesen - SC-02AB - Ignition Cover - Black - Honda CR250R Boyesen - SC-02AB - Ignition Cover - Black - Honda CR250R

    Boyesen - SC-02AB - Ignition Cover - Black - Honda CR250R

    Boyesen

    $87.95
    Boyesen - SC02AB - Ignition Cover - Black - Honda CR250RFeaturesSeals properly, guarding inside of engine from dirt and water and outlasts stock coversBoyesen Factory Covers are cast from the highest...
    $87.95
    Qty in Cart: 0
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    $87.95
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  • Out of stock
    Boyesen - SC33B - Ignition Cover - Black - Yamaha YZ125 Boyesen - SC33B - Ignition Cover - Black - Yamaha YZ125

    Boyesen - SC33B - Ignition Cover - Black - Yamaha YZ125

    Boyesen

    $87.95
    Boyesen - SC33B - Ignition Cover - Black - Yamaha YZ125FeaturesSeals properly, guarding inside of engine from dirt and water and outlasts stock coversBoyesen Factory Covers are cast from the highest...
    $87.95
    Qty in Cart: 0
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    $87.95
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  • Out of stock
    Boyesen - CC-38CB - Clutch Cover - Black - Yamaha Boyesen - CC-38CB - Clutch Cover - Black - Yamaha

    Boyesen - CC-38CB - Clutch Cover - Black - Fits Yamaha 2016-2018 WR450F, 2010-2022 YZ450F, 2016-2023 YZ450FX

    Boyesen

    $95.95
    Boyesen - 09400971 - Clutch Cover - Black - YamahaFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a perfect,...
    $95.95
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    $95.95
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  • Out of stock
    Boyesen - CC-27AB - Clutch Cover - Black - Suzuki Boyesen - CC-27AB - Clutch Cover - Black - Suzuki

    Boyesen - CC-27AB - Clutch Cover - Black - Fits 2007-2024 Suzuki RM-Z250

    Boyesen

    $95.95
    Boyesen - 09400682 - Clutch Cover - Black - SuzukiFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a perfect,...
    $95.95
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    $95.95
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  • Out of stock
    Boyesen - CC-12AB - Clutch Cover - Black - Kawasaki Boyesen - CC-12AB - Clutch Cover - Black - Kawasaki

    Boyesen - CC-12AB - Clutch Cover - Black - Kawasaki

    Boyesen

    $95.95
    Boyesen - CC12AB - Clutch Cover - Black - KawasakiFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a perfect,...
    $95.95
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    $95.95
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  • Out of stock
    Boyesen - CC-02AM - Clutch Cover - Magnesium - Honda Boyesen - CC-02AM - Clutch Cover - Magnesium - Honda

    Boyesen - CC-02AM - Clutch Cover - Magnesium - Fits 2002-2007 Honda CR250R

    Boyesen

    $95.95
    Boyesen - 09400223 - Clutch Cover - Magnesium - HondaFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a perfect,...
    $95.95
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    $95.95
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  • Out of stock
    Boyesen - CC32AB - Clutch Cover - Black - Yamaha Boyesen - CC32AB - Clutch Cover - Black - Yamaha

    Boyesen - CC32AB - Clutch Cover - Black - Yamaha

    Boyesen

    $95.95
    Boyesen - CC32AB - Clutch Cover - Black - YamahaFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a perfect, leak-free...
    $95.95
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    $95.95
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  • Out of stock
    Boyesen - CC12B - Clutch Cover - Black - Kawasaki Boyesen - CC12B - Clutch Cover - Black - Kawasaki

    Boyesen - CC12B - Clutch Cover - Black - Kawasaki

    Boyesen

    $95.95
    Boyesen - CC12B - Clutch Cover - Black - KawasakiFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a perfect,...
    $95.95
    Qty in Cart: 0
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    $95.95
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  • Out of stock
    Boyesen - CC-10M - Clutch Cover - Magnesium - Kawasaki/Suzuki Boyesen - CC-10M - Clutch Cover - Magnesium - Kawasaki/Suzuki

    Boyesen - CC-10M - Clutch Cover - Magnesium - Kawasaki/Suzuki - Fits 1998-2025 Kawasaki KX85, 1998-2021 Kawasaki KX100, 2022-2025 Kawasaki KX112, 2003-2005 Suzuki RM100

    Boyesen

    $179.95
    Boyesen - 09401114 - Clutch Cover - Magnesium - Kawasaki/SuzukiFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a...
    $179.95
    Qty in Cart: 0
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    $179.95
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  • Out of stock
    Boyesen - SC-30B - Ignition Cover - Black - Yamaha Boyesen - SC-30B - Ignition Cover - Black - Yamaha

    Boyesen - SC-30B - Ignition Cover - Black - Fits Yamaha 2018-2025 YZ65, 1993-2001 YZ80, 2002-2025 YZ85

    Boyesen

    $87.95
    Boyesen - 09401107 - Ignition Cover - Black - YamahaFeaturesSeals properly, guarding inside of engine from dirt and water and outlasts stock coversBoyesen Factory Covers are cast from the highest...
    $87.95
    Qty in Cart: 0
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    $87.95
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  • Out of stock
    Boyesen - SC10AB - Ignition Cover - Black - Kawasaki/Suzuki Boyesen - SC10AB - Ignition Cover - Black - Kawasaki/Suzuki

    Boyesen - SC10AB - Ignition Cover - Black - Kawasaki/Suzuki - Fits 1990-2000 Kawasaki KX80, 2001-2025 Kawasaki KX85, 1995-2021 Kawasaki KX100, 2022-2025 Kawasaki KX112, 2003-2006 Suzuki RM100

    Boyesen

    $87.95
    Boyesen - 09401105 - Ignition Cover - Black - Kawasaki/SuzukiFeaturesSeals properly, guarding inside of engine from dirt and water and outlasts stock coversBoyesen Factory Covers are cast from the...
    $87.95
    Qty in Cart: 0
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    $87.95
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  • Out of stock
    Del West - DW-YZ250F-EV14 - Exhaust Valve - No Dish - Yamaha YZ250F '14-'17 Del West - DW-YZ250F-EV14 - Exhaust Valve - No Dish - Yamaha YZ250F '14-'17

    Del West - DW-YZ250F-EV14 - Exhaust Valve - No Dish - Yamaha YZ250F '14-'17 - Fits 2014-2017 Yamaha YZ250F

    Del West

    $171.95
    Del West - 09262721 - Exhaust Valve - No Dish - Yamaha YZ250F '14-'17FeaturesTitanium aluminide valves are designed to meet the most exacting requirementsSpecs
    $171.95
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    $171.95
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  • Out of stock
    Cylinder Works - CH3002-K01 - Cylinder Head Kit - Kawasaki | Suzuki Cylinder Works - CH3002-K01 - Cylinder Head Kit - Kawasaki | Suzuki

    Cylinder Works - CH3002-K01 - Cylinder Head Kit - Kawasaki | Suzuki - Fits 2004-2005 Kawasaki KX250F, 2004-2006 Suzuki RM-Z250

    Cylinder Works

    $720.25
    Cylinder Works - 09311019 - Cylinder Head Kit - Kawasaki | SuzukiFeaturesInclude cam caps and cam cap boltsInclude C630 (nickel/aluminum/bronze) valve seats and guidesCompetition valve jobShortened...
    $720.25
    Qty in Cart: 0
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    $720.25
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  • Out of stock
    Cometic - C3790 - Top End Gasket Kit - 90 mm - KTM/Husqvarna/Gas Gas Cometic - C3790 - Top End Gasket Kit - 90 mm - KTM/Husqvarna/Gas Gas

    Cometic - C3790 - Top End Gasket Kit - 90 mm - KTM/Husqvarna/Gas Gas - Multiple Gas Gas/Husqvarna/KTM Models

    Cometic

    $97.95
    Cometic - 09347857 - Top End Gasket Kit - 90 mm - KTM/Husqvarna/Gas GasFeaturesMLS head gaskets promote an even torque load across the gasket sealing surface, providing less bore distortion and...
    $97.95
    Qty in Cart: 0
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    $97.95
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  • Out of stock
    Cometic - C3803 - Top End Gasket Kit - Kawasaki Cometic - C3803 - Top End Gasket Kit - Kawasaki

    Cometic - C3803 - Top End Gasket Kit - Fits 2021-2025 Kawasaki KX250/X

    Cometic

    $84.95
    Cometic - 09347860 - Top End Gasket Kit - KawasakiFeaturesMLS head gaskets promote an even torque load across the gasket sealing surface, providing less bore distortion and better piston ring seal...
    $84.95
    Qty in Cart: 0
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    $84.95
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  • Out of stock
    Cometic - C3635 - Top End Gasket Kit - 79 mm - Honda Cometic - C3635 - Top End Gasket Kit - 79 mm - Honda

    Cometic - C3635 - Top End Gasket Kit - 79 mm - Fits 2018-2025 Honda CRF250R/RX

    Cometic

    $67.95
    Cometic - 09347846 - Top End Gasket Kit - 79 mm - HondaFeaturesMLS head gaskets promote an even torque load across the gasket sealing surface, providing less bore distortion and better piston ring...
    $67.95
    Qty in Cart: 0
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    $67.95
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  • Out of stock
    Cometic - C3818 - Top End Gasket Kit - 85 mm - KTM Cometic - C3818 - Top End Gasket Kit - 85 mm - KTM

    Cometic - C3818 - Top End Gasket Kit - 85 mm - Fits 2018-2025 KTM 105 Super Mini

    Cometic

    $47.95
    Cometic - 09347864 - Top End Gasket Kit - 85 mm - KTMFeaturesMLS head gaskets promote an even torque load across the gasket sealing surface, providing less bore distortion and better piston ring seal...
    $47.95
    Qty in Cart: 0
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    $47.95
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  • Out of stock
    Cometic - C3801 - Top End Gasket Kit - 96 mm - Honda Cometic - C3801 - Top End Gasket Kit - 96 mm - Honda

    Cometic - C3801 - Top End Gasket Kit - 96 mm - Fits 2021-2023 Honda CRF450R/RX/RWE

    Cometic

    $85.95
    Cometic - 09347859 - Top End Gasket Kit - 96 mm - HondaFeaturesMLS head gaskets promote an even torque load across the gasket sealing surface, providing less bore distortion and better piston ring...
    $85.95
    Qty in Cart: 0
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    $85.95
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  • Out of stock
    Cometic - C3810 - Top End Gasket Kit - 88 mm - KTM/Husqvarna/Gas Gas Cometic - C3810 - Top End Gasket Kit - 88 mm - KTM/Husqvarna/Gas Gas

    Cometic - C3810 - Top End Gasket Kit - 88 mm - KTM/Husqvarna/Gas Gas - Multiple Gas Gas/Husqvarna/KTM Models

    Cometic

    $102.95
    Cometic - 09347862 - Top End Gasket Kit - 88 mm - KTM/Husqvarna/Gas GasFeaturesMLS head gaskets promote an even torque load across the gasket sealing surface, providing less bore distortion and...
    $102.95
    Qty in Cart: 0
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    Price:
    $102.95
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  • Out of stock
    Cometic - C3786 - Top End Gasket Kit - 97 mm - Yamaha Cometic - C3786 - Top End Gasket Kit - 97 mm - Yamaha

    Cometic - C3786 - Top End Gasket Kit - 97 mm - Fits Yamaha 2021-2023 WR450F, 2020-2022 YZ450F, 2021-2023 YZ450FX

    Cometic

    $78.95
    Cometic - 09347855 - Top End Gasket Kit - 97 mm - YamahaFeaturesMLS head gaskets promote an even torque load across the gasket sealing surface, providing less bore distortion and better piston ring...
    $78.95
    Qty in Cart: 0
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    $78.95
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  • Out of stock
    Boyesen - CC-17CB - Clutch Cover - Black - Kawasaki Boyesen - CC-17CB - Clutch Cover - Black - Kawasaki

    Boyesen - CC-17CB - Clutch Cover - Black - Fits 2021-2025 Kawasaki KX250

    Boyesen

    $95.95
    Boyesen - 09402184 - Clutch Cover - Black - KawasakiFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a perfect,...
    $95.95
    Qty in Cart: 0
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    Price:
    $95.95
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  • Out of stock
    Boyesen - CC-41CM - Clutch Cover - Magnesium - KTM/Husqvarna

    Boyesen - CC-41CM - Clutch Cover - Magnesium - KTM/Husqvarna - Fits KTM 2023-2025 125 SX, 2023-2025 125 XC, 2025 150 SX, 2024-2025 150 XC-W

    Boyesen

    $95.95
    Boyesen - 09402231 - Clutch Cover - Magnesium - KTM/HusqvarnaFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a...
    $95.95
    Qty in Cart: 0
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    Price:
    $95.95
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  • Out of stock
    Boyesen - CC-17CM - Clutch Cover - Magnesium - Kawasaki

    Boyesen - CC-17CM - Clutch Cover - Magnesium - Fits 2021-2025 Kawasaki KX250

    Boyesen

    $95.95
    Boyesen - 09402230 - Clutch Cover - Magnesium - KawasakiFeaturesLightweight factory clutch covers provide years of outstanding protection; guaranteed not to warpIndividually surfaced for a perfect,...
    $95.95
    Qty in Cart: 0
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    Price:
    $95.95
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  • Out of stock
    Shindy - 30-712 - Heavy-Duty Exhaust Clamp - 1.63"-1.88"

    Shindy - 30-712 - Heavy-Duty Exhaust Clamp - 1.63"-1.88"

    Shindy

    $10.95
    Shindy - 18610871 - Heavy-Duty Exhaust Clamp - 1.63"-1.88"FeaturesMade of corrosion-resistant stainless steel for long-lasting good looksSold as eachSpecs
    $10.95
    Qty in Cart: 0
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    $10.95
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  • Out of stock
    Dei - 010209 - Positive Locking Ties - 1/4" x 14" - Stainless Steel

    Dei - 010209 - Positive Locking Ties - 1/4" x 14" - Stainless Steel

    Dei

    $8.95
    Dei - 18611549 - Positive Locking Ties - 1/4" x 14" - Stainless SteelFeaturesPerfect for securing exhaust wrap or any place a high-strength tie is neededUV and corrosion resistantMade from 316...
    $8.95
    Qty in Cart: 0
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    Price:
    $8.95
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Adding your products to cart

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.