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!
- Product
- Qty in Cart
- Quantity
- Price
- Subtotal
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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
$23.33Qty in Cart: 0Quantity:Price:$23.33Subtotal: -
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 -
MOOSE RACING Top End Gasket Kit - KTM50SX 810301
MOOSE RACING
$24.85A top-end rebuild demands gasket and seal quality you can trust—especially when you're running a high-performance 50SX. This Moose Racing kit delivers OEM-equivalent reliability at a fraction of the cost, with every component engineered to handle the...M810301- SKU:
- M810301
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- TOP END
$24.85Qty in Cart: 0Quantity:Price:$24.85Subtotal: -
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 Suzuki RM125 2001-2003 Cylinder Rebuild Kit LAS-5420K-1
LA SLEEVE
$360.95When your Suzuki RM125's top-end starts showing signs of wear, a complete rebuild with quality components is the most cost-effective way to restore lost compression and power. The LA Sleeve cylinder rebuild kit gives you everything needed to refresh your...09310418- SKU:
- 09310418
- Availability:
- Ships Same Business Day
- Weight:
- 1.90 LBS
- MATERIAL:
- CAST
- MATERIAL:
- IRON
- TYPE:
- CYLINDER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- REBUILD KIT
$360.95Qty in Cart: 0Quantity:Price:$360.95Subtotal: -
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 48.50mm Bore Kawasaki KX85 2001-2013 KA5449
LA SLEEVE
$117.95A worn cylinder sleeve compromises compression, increases blowby, and robs your KX85 of power and reliability. The LA SLEEVE KA5449 restores cylinder integrity with precision engineering, allowing you to rebuild your engine to original specifications...KA5449- SKU:
- KA5449
- Availability:
- Ships Same Business Day
- Weight:
- 0.68 LBS
- CYLINDER BORE COATING:
- CHROME-MOLY ALLOY
- TYPE:
- AC
- PRODUCT NAME:
- CYLINDER SLEEVE
- UNITS:
- EACH
- BORE SIZE METRIC:
- 48.50 MM
- COLOR/FINISH:
- CHROME
- RIDING STYLE:
- OFF-ROAD
$117.95Qty in Cart: 0Quantity:Price:$117.95Subtotal: -
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
$127.95Qty in Cart: 0Quantity:Price:$127.95Subtotal: -
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
$127.95Qty in Cart: 0Quantity:Price:$127.95Subtotal: -
LA Sleeve Cylinder Sleeve Honda CR250R 2002 2003 H5477
LA SLEEVE
$148.95A worn cylinder bore is the silent killer of two-stroke performance—compression drops, blow-by increases, and your engine bleeds power. The LA SLEEVE Cylinder Sleeve H5477 restores your Honda CR250R to OEM specifications without the expense of a complete...H5477- SKU:
- H5477
- Availability:
- Ships Same Business Day
- Weight:
- 1.14 LBS
- COLOR/FINISH:
- CHROME
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- BORE SIZE METRIC:
- 66.40 MM
- CYLINDER BORE COATING:
- CHROME-MOLY ALLOY
- PRODUCT NAME:
- CYLINDER SLEEVE
- TYPE:
- AC
$148.95 -
KIBBLEWHITE Spring Kit 30-30015
KIBBLEWHITE
$156.91Valve spring integrity is critical to engine reliability, especially in high-RPM applications where stock springs can't handle sustained load cycles. The KIBBLEWHITE Spring Kit 30-30015 delivers precise spring rates and titanium upper collars engineered...KW3030015- SKU:
- KW3030015
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- APPLICATION:
- EXHAUST
- PRODUCT NAME:
- SPRING KIT
- SPRING OPEN PRESSURE:
- 185 LB
- TYPE:
- VALVE
- APPLICATION:
- INTAKE
- RIDING STYLE:
- OFF-ROAD
- MATERIAL:
- TITANIUM
- SPRING LIFT IMPERIAL:
- 0.400'
- UNITS:
- KIT
$156.91
