Dirt Bike Engine
Dirt Bike Engine Parts at JJ Motorsports
Discover a full range of dirt bike engine components for rebuilding or upgrading your performance from JJ Motorsports. From crankshafts to cylinder heads and piston kits, these precision-engineered components ensure reliable performance. For additional upgrades, check out our full selection of off-road dirt bike parts to keep your engine running at peak efficiency on the track or trails.
Shop trusted brands like Wiseco for forged piston kits and K&N for high-flow oil filters. Explore related categories such as Dirt Bike Air and Fuel for intake upgrades or Dirt Bike Exhaust for complete systems.
Browse our in-stock inventory below with same-day shipping and expert support. Questions? Contact us for fitment advice!
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- Price
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On Sale
MOOSE RACING Water Pump Cover - Black I04-5254B
MOOSE RACING
MSRP: $101.95Now: $65.00Was: $101.95The stock cast water pump cover on your engine is vulnerable to corrosion, impact damage, and premature failure—especially under racing conditions or extended use. The MOOSE RACING Water Pump Cover delivers superior durability with a robust construction...09401933- SKU:
- 09401933
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- MATERIAL:
- BILLET ALUMINUM
- PRODUCT NAME:
- COVER
- TYPE:
- WATER PUMP
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
MSRP: $101.95Now: $65.00Was: $101.95 -
MOOSE RACING Complete Motor Gasket Kit - KX250 808455
MOOSE RACING
$58.40A complete engine and transmission rebuild demands precision gasket sealing—any leak or premature failure compromises performance and reliability. The MOOSE RACING Complete Motor Gasket Kit delivers OEM-grade quality at a fraction of OEM pricing,...M808455- SKU:
- M808455
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- PRODUCT NAME:
- GASKET
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- TYPE:
- ENGINE
$58.40 -
MOOSE RACING Complete Motor Gasket Kit - RM85 808505
MOOSE RACING
$48.17A complete engine and transmission rebuild demands precision gaskets and seals that won't fail under load—and OEM replacements can drain your budget fast. The MOOSE RACING Complete Motor Gasket Kit delivers genuine OEM-quality seals and gaskets at a...M808505- SKU:
- M808505
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- PRODUCT NAME:
- GASKET
- UNITS:
- KIT
- TYPE:
- ENGINE
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
$48.17 -
MOOSE RACING Complete Motor Gasket Kit - RM125 808548
MOOSE RACING
$65.73A complete engine and transmission rebuild demands precision gaskets and seals that won't compromise your performance or reliability. The MOOSE RACING Complete Motor Gasket Kit eliminates the hassle of sourcing individual components, delivering every...M808548- SKU:
- M808548
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- TYPE:
- ENGINE
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- PRODUCT NAME:
- GASKET
$65.73 -
MOOSE RACING Complete Motor Gasket Kit - RM125 808549
MOOSE RACING
$83.24A complete engine and transmission rebuild demands precision gaskets and seals that won't compromise your work—this kit includes everything you need without the OEM price tag. Moose Racing's domestically manufactured gasket sets use high-tech materials...M808549- SKU:
- M808549
- Availability:
- Ships Same Business Day
- Weight:
- 0.12 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- PRODUCT NAME:
- GASKET
- TYPE:
- ENGINE
- UNITS:
- KIT
$83.24 -
MOOSE RACING Complete Motor Gasket Kit - RMX250 808578
MOOSE RACING
$73.01A complete engine and transmission rebuild demands precision gasket fitment—any leak or seal failure compromises performance and reliability. The MOOSE RACING Complete Motor Gasket Kit delivers OEM-equivalent quality at a fraction of the cost, giving you...M808578- SKU:
- M808578
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- TYPE:
- ENGINE
- PRODUCT NAME:
- GASKET
- UNITS:
- KIT
$73.01 -
MOOSE RACING Complete Motor Gasket Kit - RMX250 808579
MOOSE RACING
$73.01A complete engine and transmission rebuild requires gaskets and seals that won't compromise reliability or break your budget. The MOOSE RACING Complete Motor Gasket Kit delivers OEM-quality seals at a fraction of OEM pricing, giving you the confidence to...M808579- SKU:
- M808579
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- TYPE:
- ENGINE
- PRODUCT NAME:
- GASKET
- UNITS:
- KIT
$73.01 -
MOOSE RACING Complete Motor Gasket Kit - RM250 808580
MOOSE RACING
$73.01A complete engine and transmission rebuild demands gasket and seal integrity—any leak or failure undermines months of work and thousands in parts investment. The MOOSE RACING Complete Motor Gasket Kit delivers OEM-quality components at a fraction of OEM...M808580- SKU:
- M808580
- Availability:
- Ships Same Business Day
- Weight:
- 0.18 LBS
- TYPE:
- ENGINE
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET
$73.01 -
MOOSE RACING Complete Motor Gasket Kit - YZ85 808614
MOOSE RACING
$43.80A complete engine and transmission rebuild demands precision gasket fitment and reliable sealing—any compromise risks oil leaks, loss of compression, and catastrophic failure. The MOOSE RACING Complete Motor Gasket Kit eliminates guesswork by providing...M808614- SKU:
- M808614
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- GASKET
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- TYPE:
- ENGINE
$43.80 -
MOOSE RACING Top End Gasket Kit - CR500 810271
MOOSE RACING
$23.33A top-end rebuild demands precision gaskets and seals that won't compromise your engine's integrity or reliability. The MOOSE RACING Top End Gasket Kit gives you every component needed for a complete piston replacement at a fraction of OEM pricing, with...M810271- SKU:
- M810271
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
$23.33 -
MOOSE RACING Top End Gasket Kit - CR500R 810272
MOOSE RACING
$39.34When you're rebuilding a CR500R top end, every gasket and seal matters—poor fitment or inferior materials lead to leaks, compression loss, and wasted hours on the bench. The MOOSE RACING Top End Gasket Kit delivers OEM-equivalent seals and precision-cut...M810272- SKU:
- M810272
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
$39.34 -
MOOSE RACING Top End Gasket Kit - CR500R 810273
MOOSE RACING
$45.27A top-end gasket kit is essential when rebuilding your CR500R—whether you're replacing a worn piston or performing routine maintenance. This Moose Racing kit delivers OEM-quality seals at a fraction of factory pricing, giving you the confidence to...M810273- SKU:
- M810273
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
$45.27 -
MOOSE RACING Top End Gasket Kit - XR600 810280
MOOSE RACING
$70.25A top-end rebuild demands precision gaskets and seals that won't let you down mid-season. The MOOSE RACING Top End Gasket Kit delivers OEM-quality components at a fraction of the cost, giving you the reliability of genuine seals with the affordability of...M810280- SKU:
- M810280
- Availability:
- Ships Same Business Day
- Weight:
- 0.22 LBS
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
$70.25 -
MOOSE RACING Top End Gasket Kit - 250SX/EXC 810300
MOOSE RACING
$32.09A top-end rebuild demands precision gaskets and seals that won't compromise your engine's integrity or your wallet. The MOOSE RACING Top End Gasket Kit delivers OEM-quality components at a fraction of OEM pricing, letting you confidently refresh your...M810300- SKU:
- M810300
- Availability:
- Ships Same Business Day
- Weight:
- 0.04 LBS
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- TOP END
$32.09 -
LA Sleeve Honda CR250R 1999-2000 Cylinder Rebuild Kit LAS-5375K
LA SLEEVE
$422.95If you're rebuilding a Honda CR250R top-end, you need a sleeve and piston kit that restores—or exceeds—original compression and ring seal. The LA Sleeve kit delivers measurable gains in torque and horsepower by pairing a centrifugally-spun Moly2000...09310413- SKU:
- 09310413
- Availability:
- Ships Same Business Day
- Weight:
- 2.80 LBS
- MATERIAL:
- CAST
- MATERIAL:
- IRON
- PRODUCT NAME:
- REBUILD KIT
- TYPE:
- CYLINDER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$422.95 -
LA Sleeve Sleeve and Piston Kit Yamaha YZ125 1999-2000 LAS-5378K
LA SLEEVE
$360.95A worn or damaged top-end compromises compression, throttle response, and overall engine reliability on your YZ125. The LA Sleeve Sleeve and Piston Kit restores your 2-stroke's performance with a complete rebuild solution, delivering renewed horsepower,...09310419- SKU:
- 09310419
- Availability:
- Ships Same Business Day
- Weight:
- 1.90 LBS
- MATERIAL:
- CAST
- PRODUCT NAME:
- REBUILD KIT
- TYPE:
- CYLINDER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- MATERIAL:
- IRON
$360.95 -
LA Sleeve Cylinder Sleeve Kawasaki KX125 2000 KA5429
LA SLEEVE
$131.95If you're rebuilding a KX125 engine or restoring a worn cylinder, a quality sleeve is non-negotiable—it restores bore integrity and sealing while eliminating the cost of a full cylinder replacement. The LA SLEEVE KA5429 is engineered for precision fit...KA5429- SKU:
- KA5429
- Availability:
- Ships Same Business Day
- Weight:
- 0.81 LBS
- CYLINDER BORE COATING:
- CHROME-MOLY ALLOY
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- AC
- COLOR/FINISH:
- CHROME
- PRODUCT NAME:
- CYLINDER SLEEVE
- UNITS:
- EACH
- BORE SIZE METRIC:
- 54.00 MM
$131.95 -
LA Sleeve Cylinder Sleeve Kawasaki KX125 2002 KA5473
LA SLEEVE
$131.95A worn cylinder loses compression and efficiency, directly impacting throttle response and overall engine reliability. The LA SLEEVE Cylinder Sleeve KA5473 restores your Kawasaki KX125's original performance by providing a precision-fit replacement that...KA5473- SKU:
- KA5473
- Availability:
- Ships Same Business Day
- Weight:
- 0.68 LBS
- CYLINDER BORE COATING:
- CHROME-MOLY ALLOY
- PRODUCT NAME:
- CYLINDER SLEEVE
- TYPE:
- AC
- BORE SIZE METRIC:
- 54.00 MM
- COLOR/FINISH:
- CHROME
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$131.95 -
LA Sleeve Cylinder Sleeve for 2001 Honda CR125R H5450
LA SLEEVE
$127.95Your CR125R's cylinder is the heart of engine performance—when it wears, power drops and reliability suffers. The LA SLEEVE Cylinder Sleeve H5450 restores worn cylinders to like-new condition, giving you precise piston clearance, optimal ring sealing,...H5450- SKU:
- H5450
- Availability:
- Ships Same Business Day
- Weight:
- 0.74 LBS
- COLOR/FINISH:
- CHROME
- PRODUCT NAME:
- CYLINDER SLEEVE
- UNITS:
- EACH
- BORE SIZE METRIC:
- 54.00 MM
- CYLINDER BORE COATING:
- CHROME-MOLY ALLOY
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- AC
$127.95 -
LA Sleeve Cylinder Sleeve 54mm Honda CR125R 2002 H5466
LA SLEEVE
$127.95If your CR125R is losing compression, bogging on acceleration, or showing signs of cylinder wear, a fresh sleeve restores the sealed bore surface that two-stroke performance demands. The LA SLEEVE H5466 gives you a cost-effective alternative to sourcing...H5466- SKU:
- H5466
- Availability:
- Ships Same Business Day
- Weight:
- 0.74 LBS
- BORE SIZE METRIC:
- 54.00 MM
- COLOR/FINISH:
- CHROME
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- CYLINDER SLEEVE
- UNITS:
- EACH
- CYLINDER BORE COATING:
- CHROME-MOLY ALLOY
- TYPE:
- AC
$127.95
