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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BOYESEN Ignition Cover - Black - KX125 SC-11AB
BOYESEN
$87.95Factory Ignition Cover SC11AB Professional appearance enhances your engine's aesthetic. Seals effectively to protect the engine from dirt and water. Durable construction outlasts...SC11AB- SKU:
- SC11AB
- Availability:
- Ships Same Business Day
- Weight:
- 0.64 LBS
- MATERIAL:
- ALUMINUM
- COLOR/FINISH:
- BLACK
- PRODUCT NAME:
- COVER
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- IGNITION
- UNITS:
- EACH
$87.95Qty in Cart: 0Quantity:Price:$87.95Subtotal: -
BOYESEN Ignition Cover - Black - CR500 SC03B
BOYESEN
$87.95Factory Ignition Cover SC03B Professional appearance that enhances your engine's look. Seals effectively to protect the engine from dirt and water. Durable design outlasts standard stock...SC03B- SKU:
- SC03B
- Availability:
- Ships Same Business Day
- Weight:
- 0.69 LBS
- UNITS:
- EACH
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- MODEL:
- FACTORY RACING
- COLOR/FINISH:
- BLACK
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- IGNITION
$87.95Qty in Cart: 0Quantity:Price:$87.95Subtotal: -
BOYESEN Ignition Cover - Black - CR250 SC02B
BOYESEN
$87.95Factory Ignition Cover SC02B Professional appearance enhances your engine's look. Seals effectively to protect against dirt and water intrusion. Durable design outlasts standard stock...SC02B- SKU:
- SC02B
- Availability:
- Ships Same Business Day
- Weight:
- 0.69 LBS
- MATERIAL:
- ALUMINUM
- COLOR/FINISH:
- BLACK
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- TYPE:
- IGNITION
$87.95 -
BOYESEN Ignition Cover - Black - CR125 SC01AB
BOYESEN
$87.95Factory Ignition Cover SC01AB Professional appearance enhances your bike's aesthetic. Seals effectively to protect the engine from dirt and moisture. Durable design outlasts standard...SC01AB- SKU:
- SC01AB
- Availability:
- Ships Same Business Day
- Weight:
- 0.63 LBS
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- IGNITION
- UNITS:
- EACH
- MATERIAL:
- ALUMINUM
$87.95 -
BOYESEN Clutch Cover - Black - YZ250 CC32AB
BOYESEN
$95.95A clutch cover does more than protect—it's a visual statement of your commitment to precision engineering and race-ready performance. The BOYESEN CC32AB delivers lightweight construction that reduces...CC32AB- SKU:
- CC32AB
- Availability:
- Ships Same Business Day
- Weight:
- 1.13 LBS
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- TYPE:
- CLUTCH
- RIDING STYLE:
- OFF-ROAD
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Black - RM250 CC22B
BOYESEN
$95.95A factory-spec clutch cover designed for reliability and weight savings, the Boyesen CC22B delivers the durability professional racers and serious enthusiasts demand. The lightweight construction...CC22B- SKU:
- CC22B
- Availability:
- Ships Same Business Day
- Weight:
- 1.13 LBS
- TYPE:
- CLUTCH
- COLOR/FINISH:
- BLACK
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Black - RM125 CC21AB
BOYESEN
$95.95A lightweight clutch cover reduces unsprung weight while maintaining the durability your race engine demands. Boyesen's individually surfaced design eliminates leak-prone fitment issues that plague...CC21AB- SKU:
- CC21AB
- Availability:
- Ships Same Business Day
- Weight:
- 1.06 LBS
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
$95.95 -
BOYESEN Clutch Cover - Black - KX250 CC12B
BOYESEN
$95.95If you're running KX250 race applications, clutch cover integrity directly impacts both performance reliability and engine protection. The BOYESEN CC12B delivers lightweight construction that reduces...CC12B- SKU:
- CC12B
- Availability:
- Ships Same Business Day
- Weight:
- 1.13 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- PRODUCT NAME:
- COVER
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - KX250 CC-12AB
BOYESEN
$95.95A clutch cover is one of the most visible performance components on your KX250, and the BOYESEN CC-12AB delivers both durability and aesthetics without compromising lightweight construction...CC12AB- SKU:
- CC12AB
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
- COLOR/FINISH:
- POWDER-COATED
- TYPE:
- CLUTCH
- COLOR/FINISH:
- BLACK
- PRODUCT NAME:
- COVER
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Black - KX125 CC-11AB
BOYESEN
$95.95A lightweight clutch cover is essential for reducing unsprung weight and improving your kart's power-to-weight ratio—critical gains on the track. The Boyesen CC-11AB delivers factory-level protection...CC11AB- SKU:
- CC11AB
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
- RIDING STYLE:
- OFF-ROAD
- MODEL:
- FACTORY RACING
- UNITS:
- EACH
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- TYPE:
- CLUTCH
- PRODUCT NAME:
- COVER
$95.95 -
BOYESEN Clutch Cover - Black - CR250 CC02B
BOYESEN
$95.95A factory clutch cover replacement isn't just about aesthetics—it's about maintaining the seal integrity that keeps your CR250 running clean and reliable. BOYESEN's lightweight design cuts rotational...CC02B- SKU:
- CC02B
- Availability:
- Ships Same Business Day
- Weight:
- 1.06 LBS
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- PRODUCT NAME:
- COVER
$95.95 -
BOYESEN Clutch Cover - Black - CR250 CC-02AB
BOYESEN
$95.95A clutch cover serves as both a protective barrier and a visual statement on your CR250. The BOYESEN Lightweight Clutch Cover combines race-proven durability with a factory-quality finish,...CC02AB- SKU:
- CC02AB
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- UNITS:
- EACH
- PRODUCT NAME:
- COVER
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$95.95 -
BOYESEN Clutch Cover - Black - CR125 CC01B
BOYESEN
$95.95A lightweight clutch cover is essential for reducing unsprung weight and improving your CR125's overall performance dynamics. The BOYESEN Clutch Cover delivers factory-grade protection without the...CC01B- SKU:
- CC01B
- Availability:
- Ships Same Business Day
- Weight:
- 0.94 LBS
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- COLOR/FINISH:
- BLACK
- PRODUCT NAME:
- COVER
- COLOR/FINISH:
- POWDER-COATED
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$95.95 -
BOYESEN Clutch Cover - Black - CR125 CC01AB
BOYESEN
$95.95A factory-spec clutch cover that combines lightweight construction with race-proven durability—perfect for CR125 riders who demand both performance and reliability. The individually surfaced design...CC01AB- SKU:
- CC01AB
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$95.95 -
BOYESEN Impeller Pump CRF450 WPI-06
BOYESEN
$79.95Water temperature consistency is critical to maintaining peak horsepower and engine reliability during extended racing sessions. The BOYESEN Impeller Pump WPI-06 increases coolant flow while reducing...09500026- SKU:
- 09500026
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- UNITS:
- EACH
- MATERIAL:
- ALUMINUM
- PRODUCT NAME:
- IMPELLER
- MODEL:
- SUPERCOOLER
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
$79.95 -
BOYESEN Impeller Water Pump Cover - Black - YZ125 WPK-31AB
BOYESEN
$219.95Stock water pumps can't keep pace with the demands of high-RPM racing, leaving your YZ125 vulnerable to thermal stress and performance loss. The BOYESEN Impeller Water Pump Cover delivers measurably...09401471- SKU:
- 09401471
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- PRODUCT NAME:
- IMPELLER
- TYPE:
- WATER PUMP
- UNITS:
- KIT
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- NAUTILUS
- BASE COLOR:
- BLACK
- MATERIAL:
- ALUMINUM
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER
$219.95 -
BOYESEN Clutch Cover - Gold - Kawasaki CC-18AM
BOYESEN
$95.95If you're serious about reducing rotating mass and improving engine response, a lightweight clutch cover is a straightforward upgrade that delivers measurable results. The BOYESEN CC-18AM is...09401466- SKU:
- 09401466
- Availability:
- Ships Same Business Day
- Weight:
- 0.90 LBS
- COLOR/FINISH:
- MAGNESIUM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- TYPE:
- CLUTCH
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Black - Kawasaki CC-18AB
BOYESEN
$95.95A clutch cover does more than protect—it's a visual statement of your commitment to precision engineering and race-ready aesthetics. The BOYESEN Clutch Cover delivers lightweight construction without...09401465- SKU:
- 09401465
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- RIDING STYLE:
- OFF-ROAD
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- TYPE:
- CLUTCH
- COLOR/FINISH:
- BLACK
- UNITS:
- EACH
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Gold - KTM/Husqvarna CC-45AM
BOYESEN
$95.95Factory-spec clutch covers take a beating in competitive riding, and OEM units are prone to leaks and premature wear. The BOYESEN CC-45AM delivers race-proven durability with CNC-precision machining...09401462- SKU:
- 09401462
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- UNITS:
- EACH
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- STREET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Black - KTM/Husqvarna CC-45AB
BOYESEN
$95.95A factory-grade clutch cover protects one of your engine's most critical components while reducing rotational mass—critical on the track where every ounce matters. The BOYESEN CC-45AB is individually...09401461- SKU:
- 09401461
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- RIDING STYLE:
- STREET
- TYPE:
- CLUTCH
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal:
