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 Clutch Cover - Orange - KTM CC-41O
BOYESEN
$105.95A clutch cover does more than protect—it's a visible statement of your build's quality and attention to detail. The BOYESEN Orange Clutch Cover combines lightweight construction with precision engineering to eliminate oil weepage while keeping your KTM...09401230- SKU:
- 09401230
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- STREET
- UNITS:
- EACH
- COLOR/FINISH:
- ORANGE
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$105.95Qty in Cart: 0Quantity:Price:$105.95Subtotal: -
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 Ignition Cover - Gold - KTM 65 SC-40AM
BOYESEN
$87.95The stock ignition cover on your KTM 65 is vulnerable to the elements—dirt, water, and debris will eventually compromise its seal and appearance. The BOYESEN Factory Ignition Cover replaces that weak point with a precision-cast aluminum component that...09401226- SKU:
- 09401226
- Availability:
- Ships Same Business Day
- Weight:
- 0.57 LBS
- COLOR/FINISH:
- MAGNESIUM
- MATERIAL:
- ALUMINUM
- MODEL:
- FACTORY RACING
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- IGNITION
- COLOR/FINISH:
- POWDER-COATED
- UNITS:
- EACH
$87.95Qty in Cart: 0Quantity:Price:$87.95Subtotal: -
BOYESEN Clutch Cover - Gold CC-30M
BOYESEN
$95.95A clutch cover does more than protect—it's a visible statement of your commitment to quality and performance. The BOYESEN Lightweight Clutch Cover CC-30M delivers factory-grade durability without unnecessary weight, helping you shed rotational mass where...09401125- SKU:
- 09401125
- Availability:
- Ships Same Business Day
- Weight:
- 0.68 LBS
- UNITS:
- EACH
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- COLOR/FINISH:
- MAGNESIUM
- PRODUCT NAME:
- COVER
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
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 - Gold CC-26AM
BOYESEN
$95.95A clutch cover isn't just cosmetic—it's your first line of defense against premature wear, contamination, and catastrophic failure. The BOYESEN Clutch Cover CC-26AM delivers lightweight construction without compromising durability, making it the choice...09401123- SKU:
- 09401123
- Availability:
- Ships Same Business Day
- Weight:
- 0.97 LBS
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
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 -
BOYESEN Clutch Cover - Black CC-18B
BOYESEN
$95.95A quality clutch cover does more than protect—it's the foundation for a reliable, leak-free clutch system that won't let you down on track or trail. The BOYESEN CC-18B delivers lightweight construction without sacrificing durability, so you get the...09401119- SKU:
- 09401119
- Availability:
- Ships Same Business Day
- Weight:
- 0.82 LBS
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- ATV
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN HY-FLO Water Pump Elbow WPE-18M
BOYESEN
$29.95Cavitation in your cooling system directly kills engine performance and longevity—and stock water pump elbows are notorious for trapping heat and air pockets in their angled passages. The Boyesen HY-FLO Water Pump Elbow eliminates that design flaw with a...09401101- SKU:
- 09401101
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- PRODUCT NAME:
- ELBOW
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- EACH
- BASE COLOR:
- BLACK
- COLOR/FINISH:
- MAGNESIUM
- MODEL:
- HY-FLO
$29.95Qty in Cart: 0Quantity:Price:$29.95Subtotal: -
BOYESEN HY-FLO Water Pump Elbow WPE-18B
BOYESEN
$29.95Cavitation and heat buildup in your cooling system directly reduce engine reliability and performance—especially under sustained high-rpm racing conditions. The BOYESEN HY-FLO Water Pump Elbow eliminates the angled passages where these problems...09401100- SKU:
- 09401100
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- TYPE:
- WATER PUMP
- BASE COLOR:
- BLACK
- PRODUCT NAME:
- ELBOW
- MODEL:
- HY-FLO
$29.95Qty in Cart: 0Quantity:Price:$29.95Subtotal: -
BOYESEN Impeller/Waterpump Cover WPK-38AM
BOYESEN
$194.95Cooling system efficiency directly impacts engine longevity and performance consistency under sustained load. The BOYESEN WPK-38AM delivers measurable flow improvements across the entire RPM range, keeping combustion temperatures stable and reducing...09400978- SKU:
- 09400978
- Availability:
- Ships Same Business Day
- Weight:
- 0.35 LBS
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- COLOR/FINISH:
- POWDER-COATED
- MATERIAL:
- ALUMINUM
- MODEL:
- SUPERCOOLER
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- MAGNESIUM
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$194.95 -
BOYESEN Impeller/Waterpump Cover WPK-38AB
BOYESEN
$194.95Engine coolant flow directly impacts thermal stability and longevity—inadequate circulation forces your engine to work harder and run hotter, compromising performance and reliability. The BOYESEN Impeller/Waterpump Cover WPK-38AB uses a patented...09400977- SKU:
- 09400977
- Availability:
- Ships Same Business Day
- Weight:
- 0.36 LBS
- BASE COLOR:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- MODEL:
- SUPERCOOLER
- TYPE:
- WATER PUMP
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- BLACK
- MATERIAL:
- ALUMINUM
$194.95 -
BOYESEN Impeller/Waterpump Cover WPK-07AM
BOYESEN
$194.95Stock water pump covers restrict coolant flow, forcing your engine to work harder to maintain optimal operating temperature. The BOYESEN Impeller/Waterpump Cover WPK-07AM replaces that restriction with a high-flow design that increases circulation across...09400975- SKU:
- 09400975
- Availability:
- Ships Same Business Day
- Weight:
- 0.36 LBS
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- BASE FINISH:
- POWDER-COATED
- UNITS:
- KIT
- COLOR/FINISH:
- MAGNESIUM
- MATERIAL:
- ALUMINUM
$194.95 -
BOYESEN Impeller/Waterpump Cover WPK-07AB
BOYESEN
$194.95Engine cooling efficiency directly impacts performance, reliability, and longevity—especially under high-demand conditions. The BOYESEN WPK-07AB water pump cover and impeller combo increases coolant flow across the entire RPM range, maintaining lower,...09400974- SKU:
- 09400974
- Availability:
- Ships Same Business Day
- Weight:
- 0.36 LBS
- BASE COLOR:
- BLACK
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- SUPERCOOLER
- PRODUCT NAME:
- COVER AND IMPELLER KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- WATER PUMP
- BASE FINISH:
- POWDER-COATED
- COLOR/FINISH:
- BLACK
- MATERIAL:
- ALUMINUM
$194.95Qty in Cart: 0Quantity:Price:$194.95Subtotal: -
BOYESEN Clutch Cover - YZ450F/X CC-38CM
BOYESEN
$95.95A factory-spec clutch cover that combines lightweight construction with race-proven durability—exactly what you need to reduce rotating mass while maintaining reliable protection on the track or trail. The individually surfaced design guarantees a...09400972- SKU:
- 09400972
- Availability:
- Ships Same Business Day
- Weight:
- 0.81 LBS
- MODEL:
- FACTORY RACING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- UNITS:
- EACH
- COLOR/FINISH:
- MAGNESIUM
- COLOR/FINISH:
- POWDER-COATED
- PRODUCT NAME:
- COVER
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - YZ450F/X CC-38CB
BOYESEN
$95.95A factory-spec clutch cover that delivers the lightweight advantage you need on the track without compromising protection or longevity. Boyesen's individually surfaced design eliminates the fitment guesswork—you get a perfect seal right out of the box...09400971- SKU:
- 09400971
- Availability:
- Ships Same Business Day
- Weight:
- 0.81 LBS
- COLOR/FINISH:
- BLACK
- RIDING STYLE:
- OFF-ROAD
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- UNITS:
- EACH
- PRODUCT NAME:
- COVER
$95.95Qty in Cart: 0Quantity:Price:$95.95Subtotal: -
BOYESEN Clutch Cover - CRF250R CC-07AM
BOYESEN
$117.95If you're running a CRF250R in competition or pushing hard on the track, your clutch cover takes a beating from heat, debris, and vibration. The BOYESEN Clutch Cover CC-07AM replaces that worn or damaged stock cover with a lightweight, purpose-built...09400969- SKU:
- 09400969
- Availability:
- Ships Same Business Day
- Weight:
- 0.81 LBS
- COLOR/FINISH:
- MAGNESIUM
- RIDING STYLE:
- OFF-ROAD
- COLOR/FINISH:
- POWDER-COATED
- MODEL:
- FACTORY RACING
- TYPE:
- CLUTCH
- UNITS:
- EACH
- PRODUCT NAME:
- COVER
$117.95 -
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 protection your CRF250R needs without the weight penalty...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
$117.95
