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 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...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...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...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...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...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...M810273- SKU:
- M810273
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
$45.27Qty in Cart: 0Quantity:Price:$45.27Subtotal: -
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...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...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...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...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...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...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...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...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
$117.95 -
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...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...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- 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 -
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...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
$167.88Valve 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...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
$167.88 -
KIBBLEWHITE Intake Valve 30-3003
KIBBLEWHITE
$37.55If you're building a high-revving engine or restoring a race-proven platform, intake valve quality directly impacts combustion efficiency, thermal management, and long-term reliability. KIBBLEWHITE's...KW303003- SKU:
- KW303003
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
- HEAD DIAMETER METRIC:
- 36.00 MM
- LENGTH IMPERIAL:
- 4.165'
- MODEL:
- BLACK DIAMOND™
- TULIP ANGLE:
- 23°
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- APPLICATION:
- INTAKE
- PRODUCT NAME:
- VALVE
- STEM DIAMETER IMPERIAL:
- 0.2590'
$37.55
