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 - 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 covers. Crafted from premium aluminum for strength...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 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 rotating mass without compromising durability, while...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
$95.95 -
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 reduces unsprung mass without compromising protection,...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
$95.95 -
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 generic covers, keeping your RM125 sealed tight through...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 rotating mass while maintaining the structural...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
$95.95 -
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 without the excess mass, letting your KX125 respond...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 mass without compromising the durability you need for...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, eliminating the performance drag and aesthetic compromises of...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 excess mass of OEM units, while its precision-surfaced...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 eliminates common leak points, while the powder-coated...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 hydraulic friction, keeping your CRF450 running cooler...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 higher coolant flow across the entire RPM band, keeping...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 Ignition Cover - Orange - KTM SC-41CO
BOYESEN
$97.95Stock ignition covers are vulnerable to dirt, water, and premature wear—especially in demanding riding conditions. The Boyesen SC-41CO Factory Ignition Cover is cast from high-grade aluminum to provide reliable protection while maintaining a lightweight...09401447- SKU:
- 09401447
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
- COLOR/FINISH:
- ORANGE
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- IGNITION
$97.95 -
BOYESEN Ignition Cover - Gold - KTM/Husqvarna SC-41CM
BOYESEN
$87.95Your engine's internals face constant threats from dust, moisture, and debris—especially in trail and off-road conditions. The BOYESEN Ignition Cover replaces the factory plastic alternative with a precision-cast aluminum design that seals reliably and...09401446- SKU:
- 09401446
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- IGNITION
- UNITS:
- EACH
$87.95 -
BOYESEN Clutch Cover - Orange - KTM CC-44AO
BOYESEN
$105.95A lightweight clutch cover is essential for reducing rotating mass and improving engine responsiveness, especially in competitive racing environments where every gram matters. The BOYESEN CC-44AO delivers factory-grade protection without the weight...09401233- SKU:
- 09401233
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- COLOR/FINISH:
- ORANGE
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- STREET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$105.95 -
BOYESEN Clutch Cover - Gold - KTM CC-41M
BOYESEN
$95.95A factory-style clutch cover that combines lightweight construction with race-proven durability—essential if you're serious about reducing unsprung weight without sacrificing protection. The individually surfaced design guarantees a leak-free seal right...09401229- SKU:
- 09401229
- Availability:
- Ships Same Business Day
- Weight:
- 0.83 LBS
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- STREET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$95.95 -
BOYESEN Clutch Cover - Black CC-41B
BOYESEN
$95.95A clutch cover does more than protect—it's a visible statement of your commitment to quality and performance. The BOYESEN CC-41B delivers a lightweight design that reduces rotating mass while maintaining the durability your engine demands, backed by...09401228- SKU:
- 09401228
- Availability:
- Ships Same Business Day
- Weight:
- 0.82 LBS
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- STREET
- TYPE:
- CLUTCH
$95.95 -
BOYESEN Clutch Cover - Black CC-30B
BOYESEN
$95.95A clutch cover does more than protect your engine—it's a visible statement of your commitment to quality and performance. The BOYESEN CC-30B delivers lightweight construction without compromise, shedding unnecessary weight while maintaining the...09401124- SKU:
- 09401124
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 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 Clutch Cover - Black CC-26AB
BOYESEN
$95.95Factory clutch covers take a beating on the track and street—exposure to heat cycles, debris, and constant vibration degrades stock designs and creates leak points that compromise engine reliability. The BOYESEN Clutch Cover CC-26AB delivers lightweight...09401122- SKU:
- 09401122
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- COLOR/FINISH:
- POWDER-COATED
- UNITS:
- EACH
- COLOR/FINISH:
- BLACK
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- OFF-ROAD
$95.95 -
BOYESEN Clutch Cover - Gold CC-18M
BOYESEN
$95.95A clutch cover does more than just protect—it's a visible statement of your commitment to precision engineering and race-proven durability. The BOYESEN Clutch Cover CC-18M delivers lightweight construction without sacrificing the protective seal your...09401120- SKU:
- 09401120
- Availability:
- Ships Same Business Day
- Weight:
- 0.81 LBS
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- COLOR/FINISH:
- MAGNESIUM
$95.95
