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 Impeller/Waterpump Cover - Black WPK-18B
BOYESEN
$194.95Engine cooling efficiency directly impacts both performance and longevity, especially under sustained high-RPM operation. The Boyesen WPK-18B water pump cover and impeller assembly increases coolant...09400576- SKU:
- 09400576
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- BLACK
- MATERIAL:
- ALUMINUM
- MODEL:
- SUPERCOOLER
- TYPE:
- WATER PUMP
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BASE COLOR:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER AND IMPELLER KIT
$194.95Qty in Cart: 0Quantity:Price:$194.95Subtotal: -
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...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...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
$229.95Qty in Cart: 0Quantity:Price:$229.95Subtotal: -
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...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...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...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
$95.95 -
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...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...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...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
$194.95Qty in Cart: 0Quantity:Price:$194.95Subtotal: -
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...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...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
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
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...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...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...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...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...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...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...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
$194.95 -
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...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...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:
