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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On Sale
COMETIC Stator Gasket - Yamaha EC471020F
COMETIC
MSRP: $9.95Now: $8.96Was: $9.95A quality stator gasket is critical to preventing oil seepage and maintaining engine integrity, especially under high-RPM conditions. The COMETIC EC471020F eliminates the frustration of gasket...09344463- SKU:
- 09344463
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- MATERIAL:
- ALUMINUM
- MODEL:
- HI-PERFORMANCE
- TYPE:
- STATOR COVER
- PRODUCT NAME:
- GASKET
MSRP: $9.95Now: $8.96Was: $9.95 -
On Sale
COMETIC Stator Gasket - KTM EC494032AFM
COMETIC
MSRP: $21.95Now: $19.76Was: $21.95OEM stator cover gaskets fail prematurely due to adhesion to engine cases and material degradation under sustained heat cycles. The COMETIC Stator Gasket eliminates both problems with an AFM...09344465- SKU:
- 09344465
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- STATOR COVER
- MODEL:
- HI-PERFORMANCE
- THICKNESS IMPERIAL:
- 0,032'
- MATERIAL:
- AFM (ALUMINUM FOAM MATERIAL)
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- ATV
- THICKNESS:
- 0,81 MM (0,032')
- THICKNESS METRIC:
- 0.81 MM
- UNITS:
- EACH
MSRP: $21.95Now: $19.76Was: $21.95Qty in Cart: 0Quantity:Price:MSRP: $21.95Now: $19.76Was: $21.95Subtotal: -
On Sale
COMETIC Clutch Gasket - KTM EC496032AFM
COMETIC
MSRP: $21.95Now: $19.76Was: $21.95A leaking clutch cover gasket costs you time and money—whether through lost oil, extended service intervals, or emergency repairs. The COMETIC Clutch Gasket (EC496032AFM) eliminates these headaches...09344466- SKU:
- 09344466
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH COVER
- PRODUCT NAME:
- GASKET
- UNITS:
- EACH
- MODEL:
- HI-PERFORMANCE
- THICKNESS IMPERIAL:
- 0,032'
MSRP: $21.95Now: $19.76Was: $21.95 -
On Sale
COMETIC Exhaust Gasket EX006042AM
COMETIC
MSRP: $7.95Now: $7.16Was: $7.95A failing exhaust gasket doesn't just leak—it compromises your engine's efficiency and can mask real performance issues under the hood. The COMETIC EX006042AM delivers reliable, high-temperature...09344513- SKU:
- 09344513
- Availability:
- Ships Same Business Day
- Weight:
- 0.06 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- SET
- BORE SIZE METRIC:
- 58.00 MM
- PRODUCT NAME:
- GASKET
- MODEL:
- HI-PERFORMANCE
- TYPE:
- EXHAUST
MSRP: $7.95Now: $7.16Was: $7.95 -
On Sale
COMETIC Exhaust Gasket EX008042AM
COMETIC
MSRP: $7.95Now: $7.16Was: $7.95Exhaust gasket failure doesn't just cause leaks—it compromises your entire system's performance and allows unmetered air into your engine. The COMETIC EX008042AM is engineered to seal consistently...09344515- SKU:
- 09344515
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 68.00 MM
- PRODUCT NAME:
- GASKET
- MODEL:
- HI-PERFORMANCE
- TYPE:
- EXHAUST
- UNITS:
- SET
MSRP: $7.95Now: $7.16Was: $7.95Qty in Cart: 0Quantity:Price:MSRP: $7.95Now: $7.16Was: $7.95Subtotal: -
On Sale
COMETIC Exhaust Gasket EX651
COMETIC
MSRP: $11.95Now: $10.76Was: $11.95Exhaust gasket failure compromises engine sealing and can lead to costly leaks and performance loss. The COMETIC EX651 uses a dual-layer construction with Viton® rubber coating and Armor-400...09344544- SKU:
- 09344544
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET
- MODEL:
- HI-PERFORMANCE
- TYPE:
- EXHAUST
- UNITS:
- SET
MSRP: $11.95Now: $10.76Was: $11.95 -
On Sale
COMETIC Exhaust Gasket - Kawasaki EX693064AM
COMETIC
MSRP: $4.95Now: $4.46Was: $4.95A compromised exhaust gasket doesn't just leak—it bleeds performance and invites catastrophic engine damage. The COMETIC EX693064AM is engineered to seal under extreme thermal stress, ensuring your...09344549- SKU:
- 09344549
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- THICKNESS IMPERIAL:
- 0,064'
- PRODUCT NAME:
- GASKET
- THICKNESS METRIC:
- 1.63 MM
- BORE SIZE IMPERIAL:
- 3.858'
- MODEL:
- HI-PERFORMANCE
- TYPE:
- EXHAUST
- UNITS:
- SET
MSRP: $4.95Now: $4.46Was: $4.95Qty in Cart: 0Quantity:Price:MSRP: $4.95Now: $4.46Was: $4.95Subtotal: -
On Sale
COMETIC Exhaust Gasket - Suzuki EX877
COMETIC
MSRP: $8.95Now: $8.06Was: $8.95A failed exhaust gasket compromises both performance and reliability, allowing heat and combustion gases to escape where they shouldn't—costing you power and risking engine damage. The COMETIC EX877...09344556- SKU:
- 09344556
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- BORE SIZE METRIC:
- 101.00 MM
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET
- MODEL:
- HI-PERFORMANCE
- TYPE:
- EXHAUST
- UNITS:
- SET
MSRP: $8.95Now: $8.06Was: $8.95Qty in Cart: 0Quantity:Price:MSRP: $8.95Now: $8.06Was: $8.95Subtotal: -
On Sale
COMETIC Bottom End Gasket Set - Honda C3047BE
COMETIC
MSRP: $114.95Now: $103.46Was: $114.95A proper bottom end gasket set is non-negotiable when you're rebuilding an engine—using OEM-equivalent seals ensures oil containment, prevents coolant leaks, and maintains compression integrity from...09344079- SKU:
- 09344079
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- BOTTOM END
- BORE SIZE METRIC:
- 99.00 MM
- MODEL:
- HI-PERFORMANCE
- UNITS:
- KIT
MSRP: $114.95Now: $103.46Was: $114.95Qty in Cart: 0Quantity:Price:MSRP: $114.95Now: $103.46Was: $114.95Subtotal: -
Hot Cams Valve Shim 10.0 x 2.80 for 2008-2010 KTM 530 EXC-R 5PK1000280
HOT CAMS
$10.95Valve clearance directly impacts your 530 EXC-R's power delivery, fuel efficiency, and engine longevity—and shim wear is inevitable with high-mileage performance riding. This 5-pack of...09261293- SKU:
- 09261293
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- SHIM
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.80 MM
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
$10.95Qty in Cart: 0Quantity:Price:$10.95Subtotal: -
Hot Cams Stage 1 Camshaft for KTM 525 EXC 2003-2006 3015-1
HOT CAMS
$289.95If you're running a KTM 525 EXC and want measurable gains in torque response and mid-range power, a properly matched camshaft is one of the most cost-effective upgrades available. The Hot Cams Stage...KTM520S1A- SKU:
- KTM520S1A
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- PRODUCT NAME:
- CAMSHAFT
- TYPE:
- STAGE 1
- APPLICATION:
- INTAKE
- EXHAUST DURATION IMPERIAL:
- 261°
- INTAKE LIFT METRIC:
- 10.80 MM
- EXHAUST LIFT METRIC:
- 10.20 MM
- INTAKE DURATION IMPERIAL:
- 271°
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- APPLICATION:
- EXHAUST
- RIDING STYLE:
- ATV
$289.95Qty in Cart: 0Quantity:Price:$289.95Subtotal: -
Hot Cams Stage 1 Intake Camshaft for 2017-2018 Yamaha YZ250F 4324-1IN
HOT CAMS
$289.95If you're serious about getting the most out of your YZ250F's engine, a high-quality intake camshaft is one of the highest-ROI upgrades you can make. The Hot Cams Stage 1 delivers measurable gains in...09251197- SKU:
- 09251197
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- PRODUCT NAME:
- CAMSHAFT
- RIDING STYLE:
- OFF-ROAD
- INTAKE LIFT METRIC:
- 9.47 MM
- TYPE:
- STAGE 1
- UNITS:
- EACH
- APPLICATION:
- INTAKE
- INTAKE DURATION IMPERIAL:
- 248.44°
$289.95Qty in Cart: 0Quantity:Price:$289.95Subtotal: -
Hot Cams Stage 2 Intake Camshaft for Yamaha YZ450F 2010-2013 4165-2IN
HOT CAMS
$321.95If you're running a YZ450F in competitive racing or serious trail riding, your stock camshaft is limiting your engine's potential. The HOT CAMS Stage 2 addresses this with a drop-in upgrade that...09250569- SKU:
- 09250569
- Availability:
- Ships Same Business Day
- Weight:
- 0.99 LBS
- INTAKE LIFT METRIC:
- 9.78 MM
- PRODUCT NAME:
- CAMSHAFT
- RIDING STYLE:
- OFF-ROAD
- APPLICATION:
- INTAKE
- INTAKE DURATION IMPERIAL:
- 265°
- UNITS:
- EACH
$321.95Qty in Cart: 0Quantity:Price:$321.95Subtotal: -
Hot Cams Stage 2 Camshaft Honda CRF 450 R 2008 1102-2
HOT CAMS
$415.95If you're running a CRF 450 R and want measurable gains in horsepower and throttle response without swapping out your existing valve springs, the Hot Cams Stage 2 Camshaft is a straightforward...09250267- SKU:
- 09250267
- Availability:
- Ships Same Business Day
- Weight:
- 0.90 LBS
- APPLICATION:
- INTAKE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- EXHAUST DURATION IMPERIAL:
- 270°
- INTAKE DURATION IMPERIAL:
- 248°
- APPLICATION:
- EXHAUST
- INTAKE LIFT METRIC:
- 10.10 MM
- PRODUCT NAME:
- CAMSHAFT
- TYPE:
- STAGE 2
- EXHAUST LIFT METRIC:
- 8.80 MM
$415.95Qty in Cart: 0Quantity:Price:$415.95Subtotal: -
Hot Cams Stage 2 Exhaust Camshaft for Yamaha YZ450F 2003-2009 4090-2E
HOT CAMS
$310.95If you're serious about extracting every last bit of performance from your YZ450F, a camshaft upgrade is one of the highest-ROI modifications available. The Hot Cams Stage 2 Exhaust Camshaft is...09250277- SKU:
- 09250277
- Availability:
- Ships Same Business Day
- Weight:
- 0.98 LBS
- PRODUCT NAME:
- CAMSHAFT
- RIDING STYLE:
- OFF-ROAD
- EXHAUST LIFT METRIC:
- 8.70 MM
- UNITS:
- EACH
- APPLICATION:
- EXHAUST
- EXHAUST DURATION IMPERIAL:
- 254°
- TYPE:
- STAGE 2
$310.95Qty in Cart: 0Quantity:Price:$310.95Subtotal: -
Hot Cams Exhaust Valve Steel Honda CRF450R 2013-2020 8400027-5
HOT CAMS
$54.95The exhaust valve is critical to your CRF450R's combustion efficiency—a worn or inferior valve directly impacts power delivery, fuel economy, and engine longevity. The HOT CAMS 8400027-5 is a forged,...09262913- SKU:
- 09262913
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- COLOR/FINISH:
- BLACK
- STEM DIAMETER METRIC:
- 4.980 MM
- APPLICATION:
- EXHAUST
- BASE COLOR:
- BLACK
- PRODUCT NAME:
- VALVE
- UNITS:
- EACH
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
$54.95 -
Hot Cams Valve Shim 10.00mm x 2.20mm for 2008-2010 KTM 530 EXC-R 5PK1000220
HOT CAMS
$10.95Valve clearance directly affects your 530 EXC-R's combustion efficiency, fuel economy, and engine longevity. Over time, thermal cycling causes shims to wear, requiring periodic replacement to...09261281- SKU:
- 09261281
- Availability:
- Ships Same Business Day
- Weight:
- 0.01 LBS
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- TYPE:
- VALVE
- MATERIAL:
- STEEL
- PRODUCT NAME:
- SHIM
- UNITS:
- 5 PACK
- RIDING STYLE:
- OFF-ROAD
- VALVE SHIM THICKNESS METRIC:
- 2.20 MM
$10.95Qty in Cart: 0Quantity:Price:$10.95Subtotal: -
Hot Cams Valve Shim 7.48mm x 1.95mm for Honda CRF 250R 2004-2017 5PK748195
HOT CAMS
$11.50Valve clearance drift is inevitable in high-mileage engines—even small deviations reduce combustion efficiency and accelerate wear. Hot Cams valve shims deliver the precision adjustment your CRF 250R...09261317- SKU:
- 09261317
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE
- VALVE SHIM THICKNESS METRIC:
- 1.95 MM
- OUTSIDE DIAMETER METRIC:
- 7.48 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
$11.50 -
Hot Cams Valve Shim 7.48mm x 2.10mm for Honda CRF150R 2007-2016 5PK748210
HOT CAMS
$11.50Valve clearance directly impacts your CRF150R's horsepower delivery, fuel efficiency, and engine longevity. Hot Cams valve shims are precision-engineered to maintain exact tolerances, preventing...09261320- SKU:
- 09261320
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- OUTSIDE DIAMETER METRIC:
- 7.48 MM
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.10 MM
- PRODUCT NAME:
- SHIM
- TYPE:
- VALVE
- UNITS:
- 5 PACK
$11.50 -
Hot Cams Valve Shim 7.48mm x 2.15mm for Honda CRF 150R 2007-2018 5PK748215
HOT CAMS
$11.50Valve shim clearance directly impacts cam timing accuracy and engine responsiveness—neglect it, and you'll lose horsepower and risk valve damage. The Hot Cams 7.48mm x 2.15mm Valve Shim pack gives...09261321- SKU:
- 09261321
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- VALVE SHIM THICKNESS METRIC:
- 2.15 MM
- OUTSIDE DIAMETER METRIC:
- 7.48 MM
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- SHIM
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
$11.50
