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!
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- Quantity
- Price
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On Sale
PROX Top End Gasket Set - Gas Gas/Husqvarna/KTM 35.6439
PROX
MSRP: $99.95Now: $81.00Was: $99.95A top-end rebuild demands gasket integrity—any leak compromises compression and performance. The PROX Top End Gasket Set delivers OEM-equivalent sealing across all critical combustion chamber...09347777- SKU:
- 09347777
- Availability:
- Ships Same Business Day
- Weight:
- 0.24 LBS
MSRP: $99.95Now: $81.00Was: $99.95 -
On Sale
PROX Piston Kit - 77.96 mm - Kawasaki KX250/KX250X 01.4351.A
PROX
MSRP: $188.95Now: $158.00Was: $188.95A worn or damaged piston directly compromises your KX250/KX250X's compression, throttle response, and overall reliability. The PROX 77.96 mm Piston Kit restores factory performance specifications...09106786- SKU:
- 09106786
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
MSRP: $188.95Now: $158.00Was: $188.95 -
On Sale
ATHENA Piston Kit with Gaskets - 71.94 mm - KTM P4C0720083002B
ATHENA
MSRP: $220.95Now: $199.00Was: $220.95If you're running a 2-stroke KTM off-road machine, piston wear directly impacts your power delivery and engine reliability. The ATHENA Piston Kit restores—or exceeds—OE performance with...09031775- SKU:
- 09031775
- Availability:
- Ships Same Business Day
- Weight:
- 1.54 LBS
MSRP: $220.95Now: $199.00Was: $220.95 -
On Sale
ATHENA Piston Kit with Gaskets - 44.45 mm - Kawasaki P4C0445008001A
ATHENA
MSRP: $115.95Now: $104.00Was: $115.95Your 2-stroke off-road engine demands precision components that can handle extreme combustion pressures and rapid thermal cycling. The ATHENA Piston Kit delivers OE-equivalent reliability with...09031782- SKU:
- 09031782
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
MSRP: $115.95Now: $104.00Was: $115.95 -
On Sale
ATHENA Piston Kit with Gaskets - 53.96 mm - Yamaha P4C0540118014B
ATHENA
MSRP: $145.95Now: $131.00Was: $145.95When you're pushing a 2-stroke off-road engine to its limits, piston reliability becomes non-negotiable. The ATHENA Piston Kit delivers OE-level dependability with measurably improved durability and...09031787- SKU:
- 09031787
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
MSRP: $145.95Now: $131.00Was: $145.95 -
On Sale
PROX Cam Chain - T106ER - 110 Links - Gas Gas | Husqvarna | KTM 31.6356
PROX
MSRP: $88.95Now: $72.00Was: $88.95A worn or failing cam chain compromises valve timing precision and can lead to catastrophic engine damage if it breaks during operation. The PROX T106ER delivers OEM-equivalent reliability with...09251201- SKU:
- 09251201
- Availability:
- Ships Same Business Day
- Weight:
- 0.54 LBS
MSRP: $88.95Now: $72.00Was: $88.95 -
On Sale
PROX Cam Chain - 98XRH2010 - 114 Links - Yamaha 31.2414
PROX
MSRP: $77.95Now: $64.00Was: $77.95A worn or damaged cam chain compromises valve timing precision and can lead to catastrophic engine failure. The PROX 98XRH2010 delivers OEM-spec reliability with enhanced durability through advanced...09250825- SKU:
- 09250825
- Availability:
- Ships Same Business Day
- Weight:
- 0.45 LBS
MSRP: $77.95Now: $64.00Was: $77.95 -
On Sale
BOLT Oil Change Hardware Kit - Honda OILCHG-CRF.2
BOLT
MSRP: $7.99Now: $7.19Was: $7.99Proper oil change intervals are non-negotiable for engine longevity, and using OEM-specification hardware ensures a reliable seal every time. This kit eliminates the hassle of sourcing individual...07120671- SKU:
- 07120671
- Availability:
- Ships Same Business Day
- Weight:
- 0.03 LBS
MSRP: $7.99Now: $7.19Was: $7.99 -
Hot Cams Manual Cam Chain Tensioner for KTM 250 SX-F 2005-2023 HC00146
HOT CAMS
$46.95A worn or improperly tensioned cam chain will cause timing drift, increased noise, and accelerated wear on your top-end—all of which compromise both performance and engine longevity. The Hot Cams...09251602- SKU:
- 09251602
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
$46.95 -
VERTEX Top End Piston Kit - 66.35 mm - Gas Gas | Husqvarna | KTM VTK23630B-3
VERTEX
$307.95When your top end starts showing signs of wear—whether it's lost compression, increased blow-by, or sluggish throttle response—a quality piston kit is essential to restore your bike's original...09106822- SKU:
- 09106822
- Availability:
- Ships Same Business Day
- Weight:
- 1.30 LBS
$307.95 -
On Sale
Wossner Piston Kit 94.95 mm Husqvarna FC450 2023-2024 4097DA
WOSSNER
MSRP: $214.00Now: $203.30Was: $214.00When your FC450 demands peak performance, a worn or stock piston becomes your limiting factor. The Wossner 94.95 mm Piston Kit delivers the precision engineering and durability required to sustain...09106845- SKU:
- 09106845
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
MSRP: $214.00Now: $203.30Was: $214.00 -
VERTEX Top End Gasket Kit - Gas Gas/Husqvarna/KTM 810991
VERTEX
$101.25A leaking or deteriorating top-end gasket can silently drain your engine's performance and lead to costly damage if left unchecked. This VERTEX gasket kit delivers OEM-quality sealing across all...09348014- SKU:
- 09348014
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
$101.25 -
MOOSE RACING SEAL KIT COUNTERSHAFT BET 25-4047
MOOSE RACING
$25.95Countershaft seal failure leads to oil leakage, contamination, and accelerated wear on critical drivetrain components. The MOOSE RACING SEAL KIT COUNTERSHAFT BET 25-4047 delivers OEM-quality sealing...09351195- SKU:
- 09351195
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- APPLICATION:
- COUNTERSHAFT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- SEAL KIT
$25.95 -
WINDEROSA Top End Gasket Kit - Kawasaki 550 610103
WINDEROSA
$51.03A top-end gasket kit is essential maintenance for any Kawasaki 550/610 engine—worn gaskets lead to compression loss, oil seepage, and decreased performance. WINDEROSA's comprehensive kit addresses...PD812325- SKU:
- PD812325
- Availability:
- Ships Same Business Day
- Weight:
- 0.19 LBS
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- TOP END
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
$51.03 -
WINDEROSA Top End Gasket Kit - Raider 701 610602
WINDEROSA
$67.95A failed top-end gasket can compromise your engine's compression and introduce coolant or oil contamination into the combustion chamber—both catastrophic for performance and engine longevity. The...PD812532- SKU:
- PD812532
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- KIT
$67.95 -
WINDEROSA Gasket Kit - Standard Bore 810373
WINDEROSA
$71.97A complete gasket kit is essential for any engine rebuild or top-end refresh—it ensures reliable sealing across all critical surfaces and prevents costly coolant and oil leaks that compromise...09346009- SKU:
- 09346009
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- BORE SIZE IMPERIAL:
- STANDARD
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CYLINDER
- UNITS:
- KIT
$71.97 -
WORKS CONNECTION Engine Timing Plug - Red - Honda 24-508
WORKS CONNECTION
$46.95Stock engine timing plugs are often overlooked, but replacing them with precision-machined alternatives eliminates wobbling, improves reliability, and gives your engine bay a finished, professional...09500092- SKU:
- 09500092
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- COLOR/FINISH:
- ANODIZED
- MATERIAL:
- 6061 T-6 ALUMINUM
- COLOR/FINISH:
- RED
- TYPE:
- ENGINE
- UNITS:
- SET
- PRODUCT NAME:
- PLUG
- RIDING STYLE:
- OFF-ROAD
$46.95 -
MOOSE RACING Crankcase Bearing and Seal Kit 24-1008
MOOSE RACING
$83.95A crankshaft bearing failure doesn't just sideline your engine—it can cause catastrophic internal damage that ends a season or a rebuild investment. The MOOSE RACING 24-1008 kit delivers OEM-quality...A241008- SKU:
- A241008
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- PRODUCT NAME:
- BEARING KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- CRANK
$83.95 -
MOOSE RACING Inner Clutch Cover Gasket 816213
MOOSE RACING
$13.18A leaking clutch cover gasket compromises engine sealing and invites oil loss—replacing it is essential maintenance for any rebuild or repair. This Moose Racing gasket delivers OEM-equivalent fitment...09346127- SKU:
- 09346127
- Availability:
- Ships Same Business Day
- Weight:
- 0.16 LBS
- PRODUCT NAME:
- GASKET
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH COVER
$13.18 -
MOOSE RACING Clutch Cover Gasket 817826
MOOSE RACING
$8.88A leaking clutch cover gasket compromises engine reliability and creates messy maintenance headaches. The Moose Racing 817826 replacement gasket seals with precision while withstanding thermal...09341460- SKU:
- 09341460
- Availability:
- Ships Same Business Day
- Weight:
- 0.04 LBS
- PRODUCT NAME:
- GASKET
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH COVER
$8.88
