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 - CRF250R CC-07AB
BOYESEN
$117.95A factory-spec clutch cover that combines lightweight construction with race-proven durability. Whether you're logging track miles or competing in regional events, the BOYESEN CC-07AB delivers the...09400968- SKU:
- 09400968
- Availability:
- Ships Same Business Day
- Weight:
- 0.81 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
$117.95Qty in Cart: 0Quantity:Price:$117.95Subtotal: -
BOYESEN Impeller/Waterpump Cover - Magnesium WPK-26AM
BOYESEN
$229.95Engine temperatures climb under sustained load, threatening reliability and power output—especially in high-performance applications where stock cooling systems fall short. The BOYESEN WPK-26AM water...09400862- SKU:
- 09400862
- Availability:
- Ships Same Business Day
- Weight:
- 0.64 LBS
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- MAGNESIUM
- MATERIAL:
- ALUMINUM
- MODEL:
- SUPERCOOLER
- TYPE:
- WATER PUMP
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER AND IMPELLER KIT
$229.95 -
BOYESEN Impeller/Waterpump Cover - Black WPK-26AB
BOYESEN
$229.95Engine cooling efficiency directly impacts performance, reliability, and longevity—especially under sustained load or competitive conditions. The BOYESEN Impeller/Waterpump Cover upgrades your...09400861- SKU:
- 09400861
- Availability:
- Ships Same Business Day
- Weight:
- 0.63 LBS
- COLOR/FINISH:
- BLACK
- MATERIAL:
- ALUMINUM
- BASE FINISH:
- POWDER-COATED
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- WATER PUMP
- BASE COLOR:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER AND IMPELLER KIT
$229.95Qty in Cart: 0Quantity:Price:$229.95Subtotal: -
BOYESEN Impeller/Waterpump Cover WPK-20M
BOYESEN
$219.95Engine cooling efficiency directly impacts performance, longevity, and reliability—especially under sustained high-RPM operation. The BOYESEN Impeller/Waterpump Cover WPK-20M delivers measurably...09400734- SKU:
- 09400734
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- TYPE:
- WATER PUMP
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- MAGNESIUM
- MATERIAL:
- ALUMINUM
$219.95 -
BOYESEN Impeller/Waterpump Cover WPK-20B
BOYESEN
$219.95Engine thermal management directly impacts reliability, longevity, and consistent performance across all RPM ranges. The BOYESEN WPK-20B addresses cooling system limitations with a high-flow water...09400733- SKU:
- 09400733
- Availability:
- Ships Same Business Day
- Weight:
- 0.29 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
$219.95Qty in Cart: 0Quantity:Price:$219.95Subtotal: -
BOYESEN Clutch Cover - Gold - KTM CC-42M
BOYESEN
$95.95A lightweight clutch cover is essential for reducing unsprung mass and improving your KTM's power-to-weight ratio—every gram counts in competitive racing. The Boyesen CC-42M combines race-proven...09400706- SKU:
- 09400706
- Availability:
- Ships Same Business Day
- Weight:
- 0.95 LBS
- COLOR/FINISH:
- MAGNESIUM
- RIDING STYLE:
- OFF-ROAD
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- UNITS:
- EACH
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER
$95.95 -
BOYESEN Clutch Cover - Black - KTM CC-42B
BOYESEN
$95.95Factory clutch covers are engineered for durability in demanding race environments, and the BOYESEN CC-42B delivers lightweight protection without compromising reliability. If you're running hard on...09400705- SKU:
- 09400705
- Availability:
- Ships Same Business Day
- Weight:
- 0.96 LBS
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- COVER
$95.95 -
BOYESEN Ignition Cover - Black SC-42B
BOYESEN
$87.95Engine covers aren't just cosmetic—they're critical protection against dirt, water, and debris that can compromise internal engine components. The Boyesen SC-42B Factory Ignition Cover combines...09400702- SKU:
- 09400702
- Availability:
- Ships Same Business Day
- Weight:
- 0.66 LBS
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- IGNITION
- UNITS:
- EACH
- COLOR/FINISH:
- BLACK
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- STREET
- MATERIAL:
- ALUMINUM
$87.95Qty in Cart: 0Quantity:Price:$87.95Subtotal: -
BOYESEN Ignition Cover - Black SC-41B
BOYESEN
$87.95Engine covers aren't just cosmetic—they're essential protection against the elements. The BOYESEN Ignition Cover keeps dirt, water, and debris out of your engine bay while maintaining a...09400699- SKU:
- 09400699
- Availability:
- Ships Same Business Day
- Weight:
- 0.71 LBS
- COLOR/FINISH:
- BLACK
- MATERIAL:
- ALUMINUM
- RIDING STYLE:
- STREET
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- IGNITION
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
$87.95 -
BOYESEN Ignition Cover - KTM 85/105 SC-46M
BOYESEN
$87.95A factory-quality ignition cover protects your engine's most vulnerable internal components from the elements—dirt, water, and debris that accelerate wear and corrosion. The BOYESEN SC-46M delivers...09400697- SKU:
- 09400697
- Availability:
- Ships Same Business Day
- Weight:
- 0.58 LBS
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- IGNITION
$87.95 -
BOYESEN Ignition Cover - KTM 85/105 SC-46B
BOYESEN
$87.95The factory ignition cover protects your KTM's engine internals from the elements while delivering the professional appearance and durability of OEM components. Boyesen's aluminum construction...09400696- SKU:
- 09400696
- Availability:
- Ships Same Business Day
- Weight:
- 0.58 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- IGNITION
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
$87.95Qty in Cart: 0Quantity:Price:$87.95Subtotal: -
BOYESEN Clutch Cover - KTM 85/105 CC-46M
BOYESEN
$95.95OEM clutch covers add unnecessary weight and restrict airflow when you need it most—the BOYESEN CC-46M replaces the stock cover with a precision-engineered alternative that cuts mass while improving...09400694- SKU:
- 09400694
- Availability:
- Ships Same Business Day
- Weight:
- 0.58 LBS
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- UNITS:
- EACH
- COLOR/FINISH:
- MAGNESIUM
- PRODUCT NAME:
- COVER
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - KTM 85/105 CC-46B
BOYESEN
$95.95A factory-spec clutch cover that combines lightweight construction with proven durability—essential for KTM 85/105 riders who demand reliability without compromising performance. The individually...09400693- SKU:
- 09400693
- Availability:
- Ships Same Business Day
- Weight:
- 0.58 LBS
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- UNITS:
- EACH
- COLOR/FINISH:
- BLACK
$95.95 -
BOYESEN Supercooler Waterpump WPK-27B
BOYESEN
$229.95Engine temperatures directly impact performance, reliability, and longevity—especially under sustained racing conditions or high-load operations. The BOYESEN Supercooler WPK-27B addresses this...09400690- SKU:
- 09400690
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- BASE COLOR:
- BLACK
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- MODEL:
- SUPERCOOLER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- BLACK
- TYPE:
- WATER PUMP
$229.95Qty in Cart: 0Quantity:Price:$229.95Subtotal: -
BOYESEN Clutch Cover - Gold CC-27AM
BOYESEN
$95.95If you're serious about reducing rotating mass and shaving weight off your engine, the BOYESEN Clutch Cover delivers the lightweight performance upgrade your bike needs without sacrificing durability...09400683- SKU:
- 09400683
- Availability:
- Ships Same Business Day
- Weight:
- 0.65 LBS
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- TYPE:
- CLUTCH
- RIDING STYLE:
- OFF-ROAD
- COLOR/FINISH:
- MAGNESIUM
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Black CC-27AB
BOYESEN
$95.95A clutch cover does more than protect your engine—it's a visual statement of your commitment to performance and precision. The BOYESEN Clutch Cover CC-27AB delivers race-grade protection with a...09400682- SKU:
- 09400682
- 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
- UNITS:
- EACH
- COLOR/FINISH:
- BLACK
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Impeller/Waterpump Cover - Magnesium WPK-09M
BOYESEN
$206.65Engine temperatures spike under sustained load, reducing efficiency and accelerating wear on critical components. The BOYESEN WPK-09M water pump cover and impeller assembly increases coolant flow...09400680- SKU:
- 09400680
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- MODEL:
- SUPERCOOLER
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$206.65Qty in Cart: 0Quantity:Price:$206.65Subtotal: -
BOYESEN Impeller/Waterpump Cover - Black WPK-09B
BOYESEN
$194.95Engine temperature management directly impacts performance, reliability, and longevity—especially under sustained load or competition conditions. The Boyesen WPK-09B upgrades your cooling system with...09400679- SKU:
- 09400679
- Availability:
- Ships Same Business Day
- Weight:
- 0.35 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 Clutch Cover - Gold - CRF450 CC-06XM
BOYESEN
$95.95Factory-spec clutch covers protect your engine's most critical component while shaving unnecessary weight—essential for racers and serious builders who demand precision fit and zero leakage...09400615- SKU:
- 09400615
- Availability:
- Ships Same Business Day
- Weight:
- 0.89 LBS
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- COLOR/FINISH:
- MAGNESIUM
$95.95 -
BOYESEN Clutch Cover - Black - CRF450 CC-06XB
BOYESEN
$95.95A clutch cover does more than protect—it defines your bike's visual identity while delivering the durability your engine demands. The BOYESEN Clutch Cover combines lightweight construction with...09400614- SKU:
- 09400614
- Availability:
- Ships Same Business Day
- Weight:
- 0.90 LBS
- PRODUCT NAME:
- COVER
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- COLOR/FINISH:
- BLACK
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal:
