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
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: $214.00Qty in Cart: 0Quantity:Price:MSRP: $214.00Now: $203.30Was: $214.00Subtotal: -
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 -
BOYESEN Water Pump Kit - Magnesium - Gas Gas/Husqvarna/KTM WPK-42M
BOYESEN
$194.95A reliable water pump is critical to maintaining optimal engine temperatures under sustained high-RPM operation, and the BOYESEN Magnesium Water Pump Kit delivers OEM-quality cooling performance with...09320309- SKU:
- 09320309
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
$194.95Qty in Cart: 0Quantity:Price:$194.95Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 95.98 mm - KX450F P5F0960072007B
ATHENA
MSRP: $263.07Now: $237.00Was: $263.07The ATHENA Piston Kit delivers the reliability you expect from OEM-quality engineering while pushing performance beyond stock limitations. Precision-engineered with high-silicon aluminum alloy and...09031751- SKU:
- 09031751
- Availability:
- Ships Same Business Day
- Weight:
- 1.53 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- TYPE:
- TOP END
- DISPLACEMENT:
- 450 CC
- MODEL:
- B
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 95.98 MM
- PISTON MATERIAL:
- FORGED
- UNITS:
- KIT
MSRP: $263.07Now: $237.00Was: $263.07Qty in Cart: 0Quantity:Price:MSRP: $263.07Now: $237.00Was: $263.07Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 87.95 mm - SXF350 P5F0880090001A
ATHENA
MSRP: $257.02Now: $231.00Was: $257.02Factory piston kits wear out and lose efficiency—upgrade to the ATHENA 87.95 mm to restore top-end power and extend engine life. This precision-engineered piston kit is built for 4-stroke off-road...09031760- SKU:
- 09031760
- Availability:
- Ships Same Business Day
- Weight:
- 1.36 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- BORE SIZE METRIC:
- 87.95 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- COMPRESSION RATIO IMPERIAL:
- 14.2:1
- DISPLACEMENT:
- 349 CC
- TYPE:
- TOP END
- MODEL:
- A
- PRODUCT NAME:
- PISTON KIT
MSRP: $257.02Now: $231.00Was: $257.02Qty in Cart: 0Quantity:Price:MSRP: $257.02Now: $231.00Was: $257.02Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 96.96 mm - YZ450F P5F0970197004B
ATHENA
MSRP: $229.95Now: $207.00Was: $229.95When your YZ450F's piston reaches the end of its service life, settling for a standard replacement means accepting compromised ring sealing and unnecessary friction losses. The ATHENA Piston Kit...09031769- SKU:
- 09031769
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- TOP END
- UNITS:
- KIT
- DISPLACEMENT:
- 450 CC
- MODEL:
- B
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 96.96 MM
- COMPRESSION RATIO IMPERIAL:
- 12.8:1
- PISTON MATERIAL:
- FORGED
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
MSRP: $229.95Now: $207.00Was: $229.95Qty in Cart: 0Quantity:Price:MSRP: $229.95Now: $207.00Was: $229.95Subtotal: -
MOOSE RACING Piston Kit MX1026
MOOSE RACING
$0.00If you're pushing your engine to the limit, a stock piston won't cut it—especially under sustained high RPM or forced induction. The MOOSE RACING Piston Kit MX1026 is engineered to handle extreme...9106488- SKU:
- 9106488
- Availability:
- Ships Same Business Day
- Weight:
- 18.40 LBS
$0.00Qty in Cart: 0Quantity:Price:$0.00Subtotal: -
MOOSE RACING Piston Kit MPX2082
MOOSE RACING
$0.00When you're pushing your engine to its limits, stock pistons simply won't cut it. The MOOSE RACING Piston Kit MPX2082 delivers race-proven durability and reduced friction through precision X-style...9106518- SKU:
- 9106518
- Availability:
- Ships Same Business Day
- Weight:
- 12.80 LBS
$0.00Qty in Cart: 0Quantity:Price:$0.00Subtotal: -
MOOSE RACING Piston Kit MPX2083A-P
MOOSE RACING
$0.00If you're pushing your engine to its limits, stock pistons won't cut it. The MOOSE RACING Piston Kit MPX2083A-P is engineered with X-style and fully-boxed race forgings that deliver the strength,...9106519- SKU:
- 9106519
- Availability:
- Ships Same Business Day
- Weight:
- 12.80 LBS
$0.00Qty in Cart: 0Quantity:Price:$0.00Subtotal: -
MOOSE RACING Piston Kit MPX2059
MOOSE RACING
$0.00Whether you're chasing lap records or rebuilding after a catastrophic failure, piston reliability is non-negotiable. The MOOSE RACING Piston Kit MPX2059 combines race-proven forging technology with...9106487- SKU:
- 9106487
- Availability:
- Ships Same Business Day
- Weight:
- 17.60 LBS
$0.00Qty in Cart: 0Quantity:Price:$0.00Subtotal: -
MOOSE RACING Piston Kit MP3031C
MOOSE RACING
$0.00High-RPM racing demands pistons engineered to handle extreme cylinder pressures without sacrificing reliability. The MOOSE RACING Piston Kit MP3031C delivers race-proven forging technology with...9106484- SKU:
- 9106484
- Availability:
- Ships Same Business Day
- Weight:
- 12.80 LBS
$0.00Qty in Cart: 0Quantity:Price:$0.00Subtotal: -
Rekluse Clutch Cover Honda CRF450R 2019-2024 RMS-0401002
REKLUSE
$0.00The stock clutch cover on your CRF450R can't handle the abuse of serious trail and race riding—rocks, logs, and hard impacts will eventually crack or dent it, compromising your bike's protection and...9402050- SKU:
- 9402050
- Availability:
- Ships Same Business Day
- Weight:
- 16.00 LBS
- COLOR/FINISH:
- ANODIZED
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
- COLOR/FINISH:
- BLACK
- MATERIAL:
- BILLET ALUMINUM
- PRODUCT NAME:
- COVER
- RIDING STYLE:
- STREET
- UNITS:
- EACH
$0.00Qty in Cart: 0Quantity:Price:$0.00Subtotal: -
Rekluse Clutch Cover Honda CRF250R 2018-2022 RMS-0401101
REKLUSE
$0.00Trail riding demands a clutch cover that can absorb punishment without compromising engine protection or oil capacity. The Rekluse RMS-0401101 delivers both durability and functional improvement over...9402103- SKU:
- 9402103
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- COLOR/FINISH:
- ANODIZED
- COLOR/FINISH:
- BLACK
- PRODUCT NAME:
- COVER
- UNITS:
- EACH
- MATERIAL:
- BILLET ALUMINUM
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH
$0.00Qty in Cart: 0Quantity:Price:$0.00Subtotal: -
MOOSE RACING Piston Kit MP3035
MOOSE RACING
$125.95Whether you're pushing peak boost or maximizing naturally aspirated output, piston durability and ring seal are non-negotiable. The MOOSE RACING Piston Kit MP3035 delivers race-proven construction...09106481- SKU:
- 09106481
- Availability:
- Ships Same Business Day
- Weight:
- 19.20 LBS
$125.95Qty in Cart: 0Quantity:Price:$125.95Subtotal: -
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 440 610101
WINDEROSA
$46.75A leaking top end gasket kit compromises combustion efficiency and invites coolant or oil contamination into your Kawasaki 440 engine—exactly what you don't need mid-season. The WINDEROSA 610101...PD812305- SKU:
- PD812305
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- TOP END
- UNITS:
- KIT
$46.75Qty in Cart: 0Quantity:Price:$46.75Subtotal: -
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 -
WORKS CONNECTION Engine Plug - Blue 24-490
WORKS CONNECTION
$31.95Stock engine plugs are functional but forgettable—and they're the first thing visible when you crack open your engine bay. The WORKS CONNECTION Engine Plug upgrades that visual real estate with...09500854- SKU:
- 09500854
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- STREET
- TYPE:
- ENGINE
- UNITS:
- SET
- COLOR/FINISH:
- BLUE
- RIDING STYLE:
- OFF-ROAD
- MATERIAL:
- 6061 T-6 ALUMINUM
- COLOR/FINISH:
- ANODIZED
- PRODUCT NAME:
- PLUG
$31.95Qty in Cart: 0Quantity:Price:$31.95Subtotal: -
WINDEROSA Gasket - Complete - JS800SXR 611409
WINDEROSA
$127.95A complete gasket set is essential for any engine rebuild or overhaul on your JS800SXR—preventing oil leaks, coolant seepage, and combustion gas escape that compromise performance and reliability...09346560- SKU:
- 09346560
- Availability:
- Ships Same Business Day
- Weight:
- 0.60 LBS
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- COMPLETE
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- ENGINE
- UNITS:
- KIT
$127.95Qty in Cart: 0Quantity:Price:$127.95Subtotal:
