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
-
BOYESEN Clutch Cover - Black - KTM 250 SX-F CC-44B
BOYESEN
$95.95A quality clutch cover does more than look the part—it protects a critical component from debris, impact, and weathering while keeping your bike lightweight. The BOYESEN Clutch Cover delivers factory-grade durability with a precision-fit design that...09400570- SKU:
- 09400570
- Availability:
- Ships Same Business Day
- Weight:
- 0.86 LBS
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- STREET
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Impeller/Waterpump Cover - Magnesium WPK-26M
BOYESEN
$229.95Engine cooling is the foundation of reliability and performance longevity—inadequate coolant flow leads to hot spots, thermal stress, and premature component failure. The Boyesen WPK-26M replaces your stock water pump cover and impeller with a high-flow...09400568- SKU:
- 09400568
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
- COLOR/FINISH:
- MAGNESIUM
- MATERIAL:
- ALUMINUM
- BASE FINISH:
- POWDER-COATED
- UNITS:
- KIT
- TYPE:
- WATER PUMP
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- RIDING STYLE:
- OFF-ROAD
$229.95 -
BOYESEN Impeller/Waterpump Cover - Black WPK-26B
BOYESEN
$229.95Engine cooling efficiency directly impacts performance and longevity—inadequate coolant flow leads to temperature spikes that compromise power output and accelerate wear. The Boyesen WPK-26B water pump cover and impeller upgrade increases coolant...09400567- SKU:
- 09400567
- Availability:
- Ships Same Business Day
- Weight:
- 0.41 LBS
- COLOR/FINISH:
- BLACK
- MATERIAL:
- ALUMINUM
- TYPE:
- WATER PUMP
- BASE FINISH:
- POWDER-COATED
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BASE COLOR:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER AND IMPELLER KIT
$229.95Qty in Cart: 0Quantity:Price:$229.95Subtotal: -
BOYESEN Clutch Cover - Gold - CRF250X CC-07XM
BOYESEN
$95.95A quality clutch cover protects one of your bike's most critical components while contributing to the overall aesthetic of your build. The BOYESEN Gold Clutch Cover combines factory-level durability with a refined look that justifies its place on any...09400565- SKU:
- 09400565
- Availability:
- Ships Same Business Day
- Weight:
- 0.65 LBS
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Black - CRF250X CC-07XB
BOYESEN
$95.95A factory clutch cover replacement needs to balance lightweight construction with durability—and the BOYESEN CC-07XB delivers both. The precision-surfaced design eliminates leaks while the powder-coated finish withstands harsh racing conditions and...09400564- SKU:
- 09400564
- Availability:
- Ships Same Business Day
- Weight:
- 0.64 LBS
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Water Pump Cover - Magnesium - KX250 WPC-12DM
BOYESEN
$129.95Your KX250's water pump is exposed to constant mud, debris, and thermal stress—a vulnerable point on any serious race bike. The BOYESEN Magnesium Water Pump Cover seals out contaminants while shedding heat efficiently, protecting your cooling system and...09400473- SKU:
- 09400473
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- MODEL:
- SUPERCOOLER
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
$129.95Qty in Cart: 0Quantity:Price:$129.95Subtotal: -
BOYESEN Water Pump Cover - Black - KX250 WPC-12DB
BOYESEN
$129.95Engine cooling integrity is non-negotiable in high-performance riding, and a compromised water pump cover can lead to coolant leaks and overheating during peak demand. The BOYESEN Water Pump Cover delivers OEM-quality protection with a hardened...09400472- SKU:
- 09400472
- Availability:
- Ships Same Business Day
- Weight:
- 0.41 LBS
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- BASE COLOR:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
$129.95Qty in Cart: 0Quantity:Price:$129.95Subtotal: -
BOYESEN Impeller/Waterpump Cover - Magnesium WPK-10M
BOYESEN
$194.95Engine temperatures spike under sustained load, compromising performance and reliability. The BOYESEN WPK-10M addresses this directly with a high-flow water pump design that increases coolant circulation across all RPM ranges, keeping your engine...09400470- SKU:
- 09400470
- Availability:
- Ships Same Business Day
- Weight:
- 0.39 LBS
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- MATERIAL:
- ALUMINUM
- MODEL:
- SUPERCOOLER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- MAGNESIUM
- TYPE:
- WATER PUMP
$194.95 -
BOYESEN Impeller/Waterpump Cover - Black WPK-10B
BOYESEN
$194.95Engine cooling efficiency directly impacts performance, reliability, and longevity—especially under sustained load or high RPM conditions. The BOYESEN WPK-10B water pump cover and impeller upgrade increases coolant flow across your entire RPM range,...09400469- SKU:
- 09400469
- Availability:
- Ships Same Business Day
- Weight:
- 0.39 LBS
- BASE COLOR:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- RIDING STYLE:
- OFF-ROAD
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- BLACK
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$194.95Qty in Cart: 0Quantity:Price:$194.95Subtotal: -
BOYESEN Clutch Cover - Gold - Kawasaki/Suzuki CC-17M
BOYESEN
$95.95If you're serious about race performance, your clutch cover needs to match your commitment to lightweight efficiency and reliability. The BOYESEN Clutch Cover eliminates unnecessary weight while delivering the precision fit and durability required in...09400446- SKU:
- 09400446
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$95.95 -
BOYESEN Clutch Cover - Gold - Kawasaki/Suzuki CC-17B
BOYESEN
$95.95If you're serious about reducing rotational mass and improving your bike's throttle response, a lightweight clutch cover is one of the easiest wins available. The BOYESEN CC-17B delivers factory-spec protection without the weight penalty, while its...09400445- SKU:
- 09400445
- Availability:
- Ships Same Business Day
- Weight:
- 0.60 LBS
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- UNITS:
- EACH
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Gold - CRF250 CC-07M
BOYESEN
$95.95The BOYESEN Clutch Cover delivers both protection and visual impact, combining lightweight construction with race-ready aesthetics. Its precision-surfaced design ensures a leak-free seal that holds up through demanding track sessions and regular riding...09400443- SKU:
- 09400443
- Availability:
- Ships Same Business Day
- Weight:
- 0.65 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
$95.95 -
BOYESEN Clutch Cover - Black - CRF250 CC-07B
BOYESEN
$95.95A clutch cover isn't just cosmetic—it's your first line of defense against impact, debris, and environmental damage during track sessions and trail riding. The BOYESEN CC-07B delivers lightweight factory-style protection without added rotational mass,...09400442- SKU:
- 09400442
- Availability:
- Ships Same Business Day
- Weight:
- 0.65 LBS
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Impeller/Waterpump Cover - Magnesium WPK-38M
BOYESEN
$194.95Engine cooling efficiency directly impacts performance and longevity. The BOYESEN WPK-38M waterpump cover and impeller combo uses a patented nautilus-style impeller design to increase coolant flow across all RPM ranges, keeping your engine running at a...09400414- SKU:
- 09400414
- Availability:
- Ships Same Business Day
- Weight:
- 0.41 LBS
- RIDING STYLE:
- OFF-ROAD
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- BASE FINISH:
- POWDER-COATED
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$194.95 -
BOYESEN Impeller/Waterpump Cover - Black WPK-38B
BOYESEN
$194.95Engine cooling efficiency directly impacts performance and longevity—especially under sustained high-RPM operation. The BOYESEN WPK-38B water pump cover and impeller combo increases coolant flow across the entire RPM band, maintaining lower, more stable...09400413- SKU:
- 09400413
- Availability:
- Ships Same Business Day
- Weight:
- 0.41 LBS
- BASE COLOR:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- MODEL:
- SUPERCOOLER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- BLACK
- MATERIAL:
- ALUMINUM
- TYPE:
- WATER PUMP
$194.95Qty in Cart: 0Quantity:Price:$194.95Subtotal: -
BOYESEN Impeller/Waterpump Cover - Black WPK-17B
BOYESEN
$229.95Engine cooling efficiency directly impacts both performance and longevity—inadequate coolant flow leads to temperature spikes, reduced power output, and accelerated wear on critical components. The BOYESEN Impeller/Waterpump Cover uses a patented...09400411- SKU:
- 09400411
- Availability:
- Ships Same Business Day
- Weight:
- 0.60 LBS
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- BASE COLOR:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$229.95Qty in Cart: 0Quantity:Price:$229.95Subtotal: -
BOYESEN Impeller/Waterpump Cover - Black WPK-12B
BOYESEN
$194.95Engine cooling efficiency directly impacts performance, reliability, and longevity—especially under sustained high-RPM conditions. The BOYESEN Impeller/Waterpump Cover upgrades your cooling system with a high-flow design that maintains lower, more stable...09400408- SKU:
- 09400408
- Availability:
- Ships Same Business Day
- Weight:
- 0.35 LBS
- BASE COLOR:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- BLACK
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$194.95Qty in Cart: 0Quantity:Price:$194.95Subtotal: -
BOYESEN Impeller/Waterpump Cover - Black WPK-07B
BOYESEN
$194.95Engine coolant flow directly impacts operating temperature stability and component longevity—especially under sustained high-RPM operation. The Boyesen WPK-07B uses a patented nautilus-style impeller geometry to increase coolant displacement across the...09400406- SKU:
- 09400406
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- BASE COLOR:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- MODEL:
- SUPERCOOLER
- TYPE:
- WATER PUMP
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- BLACK
- MATERIAL:
- ALUMINUM
$194.95 -
BOYESEN Impeller/Waterpump Cover WPK37M
BOYESEN
$194.95Engine cooling efficiency directly impacts performance, reliability, and longevity—especially under sustained high-RPM operation. The BOYESEN Impeller/Waterpump Cover WPK37M uses a patented nautilus-style impeller design to increase coolant flow across...09400404- SKU:
- 09400404
- Availability:
- Ships Same Business Day
- Weight:
- 0.37 LBS
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- RIDING STYLE:
- OFF-ROAD
- BASE FINISH:
- POWDER-COATED
- UNITS:
- KIT
- TYPE:
- WATER PUMP
- COLOR/FINISH:
- MAGNESIUM
- MATERIAL:
- ALUMINUM
$194.95Qty in Cart: 0Quantity:Price:$194.95Subtotal: -
BOYESEN Impeller/Waterpump Cover WPK37B
BOYESEN
$194.95Engine temperature stability is critical to reliability and longevity, especially under sustained load or racing conditions. The Boyesen WPK37B water pump cover and impeller upgrade increases coolant flow across all RPM ranges, allowing your engine to...09400403- SKU:
- 09400403
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
- BASE COLOR:
- BLACK
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER AND IMPELLER KIT
$194.95
