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 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...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 -
BOYESEN Impeller/Waterpump Cover WPK32AM
BOYESEN
$194.95Engine cooling efficiency directly impacts both performance and longevity, especially under sustained load or competition conditions. The BOYESEN WPK32AM water pump cover and impeller upgrade...09400402- SKU:
- 09400402
- Availability:
- Ships Same Business Day
- Weight:
- 0.31 LBS
- MODEL:
- SUPERCOOLER
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- PRODUCT NAME:
- COVER AND IMPELLER KIT
$194.95Qty in Cart: 0Quantity:Price:$194.95Subtotal: -
BOYESEN Impeller/Waterpump Cover WPK32AB
BOYESEN
$194.95Engine thermal management directly impacts reliability, performance consistency, and longevity—especially under sustained racing conditions or high-load operation. The BOYESEN Impeller/Waterpump...09400401- SKU:
- 09400401
- Availability:
- Ships Same Business Day
- Weight:
- 0.31 LBS
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- BLACK
- TYPE:
- WATER PUMP
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- MATERIAL:
- ALUMINUM
- MODEL:
- SUPERCOOLER
- BASE COLOR:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER AND IMPELLER KIT
$194.95Qty in Cart: 0Quantity:Price:$194.95Subtotal: -
BOYESEN Impeller/Waterpump Cover WPK-31B
BOYESEN
$194.95Engine coolant flow directly impacts operating temperature stability and longevity—particularly under sustained high-RPM conditions where thermal management becomes critical. The BOYESEN WPK-31B...09400399- SKU:
- 09400399
- Availability:
- Ships Same Business Day
- Weight:
- 0.35 LBS
- BASE COLOR:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$194.95 -
BOYESEN Impeller/Waterpump Cover WPK-06M
BOYESEN
$194.95Engine cooling efficiency directly impacts performance and longevity—inadequate coolant flow forces your engine to operate at inconsistent temperatures, compromising both power output and component...09400398- SKU:
- 09400398
- Availability:
- Ships Same Business Day
- Weight:
- 0.45 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
$194.95Qty in Cart: 0Quantity:Price:$194.95Subtotal: -
BOYESEN Impeller/Waterpump Cover WPK-06B
BOYESEN
$194.95Engine cooling efficiency directly impacts performance and longevity—especially under sustained high-RPM operation. The BOYESEN WPK-06B addresses this with a hydrodynamic impeller design that...09400397- SKU:
- 09400397
- Availability:
- Ships Same Business Day
- Weight:
- 0.32 LBS
- BASE COLOR:
- BLACK
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- COLOR/FINISH:
- BLACK
- MODEL:
- SUPERCOOLER
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$194.95Qty in Cart: 0Quantity:Price:$194.95Subtotal: -
BOYESEN Clutch Cover - Gold - YZ125 CC-33M
BOYESEN
$95.95A lightweight clutch cover is essential for reducing unsprung weight and improving overall bike handling, especially in competitive YZ125 applications where every fraction of a pound matters. The...09400396- SKU:
- 09400396
- Availability:
- Ships Same Business Day
- Weight:
- 0.68 LBS
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$95.95 -
BOYESEN Clutch Cover - Black - YZ125 CC-33B
BOYESEN
$95.95A clutch cover isn't just protection—it's a statement of maintenance standards and ride reliability. The BOYESEN CC-33B delivers factory-grade durability with a lightweight design that won't add...09400395- SKU:
- 09400395
- Availability:
- Ships Same Business Day
- Weight:
- 1.19 LBS
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Gold - YZ125 CC-31M
BOYESEN
$198.95A lightweight clutch cover isn't just about aesthetics—it reduces unsprung weight and heat retention while maintaining the durability your YZ125 demands in competition. The Boyesen CC-31M delivers...09400393- SKU:
- 09400393
- Availability:
- Ships Same Business Day
- Weight:
- 0.90 LBS
- COLOR/FINISH:
- MAGNESIUM
- TYPE:
- CLUTCH
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
$198.95Qty in Cart: 0Quantity:Price:$198.95Subtotal: -
BOYESEN Clutch Cover - Black - YZ125 CC-31B
BOYESEN
$198.95A clutch cover does more than protect—it's a visible statement of your commitment to race-ready precision. The Boyesen CC-31B combines lightweight construction with a factory-engineered fit that...09400392- SKU:
- 09400392
- Availability:
- Ships Same Business Day
- Weight:
- 0.86 LBS
- COLOR/FINISH:
- BLACK
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- COLOR/FINISH:
- POWDER-COATED
$198.95 -
BOYESEN Clutch Cover - Gold - KX250 CC-12CM
BOYESEN
$95.95A lightweight clutch cover reduces unsprung weight and rotational mass—critical factors in KX250 performance where every fraction matters. The BOYESEN Gold cover combines factory-grade durability...09400390- SKU:
- 09400390
- Availability:
- Ships Same Business Day
- Weight:
- 1.03 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Gold - YZ/WR250F CC-37M
BOYESEN
$95.95A lightweight clutch cover reduces unsprung weight and rotational mass, directly improving throttle response and handling characteristics on your YZ/WR250F. The factory-spec design delivers OEM...09400235- SKU:
- 09400235
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- UNITS:
- EACH
- PRODUCT NAME:
- COVER
- COLOR/FINISH:
- MAGNESIUM
$95.95 -
BOYESEN Clutch Cover - Black - YZ/WR250F CC-37B
BOYESEN
$95.95A lightweight clutch cover cuts unsprung weight and improves handling dynamics without compromising protection—critical for riders pushing lap times. Individually surfaced construction eliminates...09400234- SKU:
- 09400234
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- COLOR/FINISH:
- BLACK
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Gold - RM250 CC-22M
BOYESEN
$95.95A quality clutch cover protects one of your engine's most critical components while establishing the visual foundation of your build. The BOYESEN Clutch Cover delivers lightweight construction...09400232- SKU:
- 09400232
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- TYPE:
- CLUTCH
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Gold - RM125 CC-21AM
BOYESEN
$95.95A quality clutch cover is essential for protecting your engine's internal components while maintaining a clean, professional appearance in the paddock. The BOYESEN Clutch Cover delivers lightweight...09400231- SKU:
- 09400231
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- PRODUCT NAME:
- COVER
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
$95.95 -
BOYESEN Clutch Cover - Gold - KX250 CC-12M
BOYESEN
$95.95A factory clutch cover is critical protection for your KX250's clutch basket and internal components—one crash or debris strike can mean a complete engine teardown. The BOYESEN Gold Clutch Cover...09400229- SKU:
- 09400229
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- COLOR/FINISH:
- MAGNESIUM
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Gold - KX125 CC-11AM
BOYESEN
$95.95A clutch cover does more than protect—it's a visible statement of your commitment to precision engineering and race-ready performance. The BOYESEN Gold Clutch Cover combines lightweight construction...09400228- SKU:
- 09400228
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- UNITS:
- EACH
$95.95 -
BOYESEN Clutch Cover - Gold - CR450F CC-06M
BOYESEN
$95.95A clutch cover does more than protect—it's a visual statement of your commitment to quality and performance. The BOYESEN Gold Clutch Cover combines race-proven durability with a lightweight design...09400226- SKU:
- 09400226
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- ATV
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Black - CR450F CC-06B
BOYESEN
$95.95A clutch cover isn't just cosmetic—it's your first line of defense against debris, heat, and premature wear. The BOYESEN CC-06B delivers the lightweight construction you need for race applications...09400225- SKU:
- 09400225
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- COLOR/FINISH:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - Gold - CR250 CC-02AM
BOYESEN
$95.95If you're running a CR250 at the track or trail, your clutch cover takes a beating. The BOYESEN Lightweight Clutch Cover combines factory-level protection with measurable weight savings, helping you...09400223- SKU:
- 09400223
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- COVER
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal:
