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
-
On Sale
PROX Exhaust Valve 28.1227-1
PROX
MSRP: $30.95Now: $25.00Was: $30.95A precision exhaust valve is critical to maintaining proper combustion chamber sealing and engine performance under high RPM and sustained heat cycles. OEM-specification exhaust valves like the PROX...09260668- SKU:
- 09260668
- Availability:
- Ships Same Business Day
- Weight:
- 0.06 LBS
- UNITS:
- EACH
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- APPLICATION:
- EXHAUST
- PRODUCT NAME:
- VALVE
MSRP: $30.95Now: $25.00Was: $30.95 -
On Sale
PROX Exhaust Valve 28.1407-1
PROX
MSRP: $44.95Now: $38.00Was: $44.95A precision exhaust valve is critical to your engine's breathing efficiency and longevity. The PROX 28.1407-1 delivers OEM-specification performance with tight tolerances and premium construction,...09260677- SKU:
- 09260677
- Availability:
- Ships Same Business Day
- Weight:
- 0.09 LBS
- APPLICATION:
- EXHAUST
- PRODUCT NAME:
- VALVE
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
MSRP: $44.95Now: $38.00Was: $44.95Qty in Cart: 0Quantity:Price:MSRP: $44.95Now: $38.00Was: $44.95Subtotal: -
PROX Intake Valve and Spring Kit 28.SIS3338-2
PROX
$155.95If you're pushing your engine to the limit, OEM valve springs will eventually let you down—they simply aren't engineered for sustained high-RPM loads. The PROX Intake Valve and Spring Kit 28...09261461- SKU:
- 09261461
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- APPLICATION:
- INTAKE
- PRODUCT NAME:
- SPRING KIT
- TYPE:
- VALVE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- MATERIAL:
- TI-STEEL
$155.95Qty in Cart: 0Quantity:Price:$155.95Subtotal: -
PROX Valve and Spring Kit 28.SIS4341-2
PROX
$155.95If you're running your engine hard at high RPM, OEM valve and spring components become a limiting factor—they simply weren't engineered to handle sustained extreme conditions. The PROX 28.SIS4341-2...09261465- SKU:
- 09261465
- Availability:
- Ships Same Business Day
- Weight:
- 0.35 LBS
- APPLICATION:
- INTAKE
- PRODUCT NAME:
- SPRING KIT
- TYPE:
- VALVE
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$155.95 -
PROX Top End Gasket Set - Yamaha 35.2418
PROX
$69.95A quality top-end gasket set is essential for maintaining compression integrity and preventing costly oil leaks between cylinder head and block surfaces. PROX's gasket sets are engineered to OEM...09345708- SKU:
- 09345708
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- PRODUCT NAME:
- GASKET SET
- TYPE:
- TOP END
- UNITS:
- SET
- RIDING STYLE:
- OFF-ROAD
$69.95Qty in Cart: 0Quantity:Price:$69.95Subtotal: -
PROX Top End Gasket Set - Suzuki 35.3122
PROX
$22.95A quality top end gasket set is critical for maintaining compression, preventing oil leaks, and ensuring reliable engine sealing in high-performance applications. The PROX 35.3122 delivers...09345717- SKU:
- 09345717
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- UNITS:
- SET
- PRODUCT NAME:
- GASKET SET
- TYPE:
- TOP END
- RIDING STYLE:
- OFF-ROAD
$22.95 -
PROX Top End Gasket Set - Suzuki 35.3311
PROX
$34.95A top-end gasket set is essential maintenance for any engine rebuild or head service—it's the barrier that prevents combustion pressure and coolant from leaking past critical sealing points. The PROX...09345728- SKU:
- 09345728
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- GASKET SET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- SET
$34.95Qty in Cart: 0Quantity:Price:$34.95Subtotal: -
On Sale
PROX Top End Gasket Set - Suzuki 35.3337
PROX
MSRP: $69.95Now: $45.00Was: $69.95A degraded top end gasket set compromises seal integrity, leading to coolant leaks, oil seepage, and potential engine damage. PROX gaskets are engineered to OEM specifications, ensuring reliable...09345737- SKU:
- 09345737
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- GASKET SET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- SET
MSRP: $69.95Now: $45.00Was: $69.95Qty in Cart: 0Quantity:Price:MSRP: $69.95Now: $45.00Was: $69.95Subtotal: -
PROX Top End Gasket Set - Kawasaki 35.4215
PROX
$39.95A quality top-end gasket set is essential for maintaining compression integrity and preventing oil leakage in high-performance applications. The PROX 35.4215 gasket set is engineered to OEM...09345756- SKU:
- 09345756
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- GASKET SET
- TYPE:
- TOP END
- UNITS:
- SET
$39.95Qty in Cart: 0Quantity:Price:$39.95Subtotal: -
PROX Top End Gasket Set - Kawasaki 35.4409
PROX
$44.95A properly sealed top end is the foundation of reliable engine performance, and PROX gasket sets deliver OEM-quality sealing with precision engineering. Whether you're rebuilding after a full...09345770- SKU:
- 09345770
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- UNITS:
- SET
- PRODUCT NAME:
- GASKET SET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
$44.95Qty in Cart: 0Quantity:Price:$44.95Subtotal: -
PROX Top End Gasket Set - KTM 35.6103
PROX
$29.95A properly sealed top end is critical for maintaining combustion integrity and preventing costly oil leaks that compromise performance and engine longevity. PROX Top End Gasket Sets are engineered to...09345776- SKU:
- 09345776
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- GASKET SET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- SET
$29.95Qty in Cart: 0Quantity:Price:$29.95Subtotal: -
PROX Top End Gasket Set - KTM 35.6248
PROX
$29.95A quality top-end gasket set is critical for maintaining compression, preventing oil seepage, and ensuring reliable engine performance between rebuilds. PROX gaskets are engineered to OEM...09345783- SKU:
- 09345783
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- RIDING STYLE:
- STREET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET SET
- UNITS:
- SET
$29.95Qty in Cart: 0Quantity:Price:$29.95Subtotal: -
PROX Water Pump Rebuild Kit - Honda 57.1422
PROX
$36.95A failing water pump can compromise cooling system integrity and lead to catastrophic engine damage. The PROX Water Pump Rebuild Kit restores OEM performance with precision-engineered components,...09346993- SKU:
- 09346993
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- PRODUCT NAME:
- REPAIR KIT
- TYPE:
- WATER PUMP
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$36.95 -
PROX Water Pump Rebuild Kit - Honda 57.1515
PROX
$39.95A failing water pump compromises engine cooling efficiency and risks catastrophic overheating—especially under racing conditions or sustained high-performance driving. The PROX Water Pump Rebuild Kit...09347000- SKU:
- 09347000
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- TYPE:
- WATER PUMP
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- REPAIR KIT
$39.95Qty in Cart: 0Quantity:Price:$39.95Subtotal: -
PROX Water Pump Rebuild Kit - Suzuki 57.3425
PROX
$34.95A failing water pump compromises your engine's cooling system and puts your entire build at risk. This PROX rebuild kit gives you OEM-quality replacement components without the downtime and expense...09347035- SKU:
- 09347035
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- WATER PUMP
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- REPAIR KIT
$34.95Qty in Cart: 0Quantity:Price:$34.95Subtotal: -
PROX Water Pump Rebuild Kit - Kawasaki 57.4026
PROX
$39.95Water pump failure is one of the most common causes of catastrophic engine damage in high-performance applications. The PROX Water Pump Rebuild Kit gives you OEM-quality components at a fraction of...09347040- SKU:
- 09347040
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- REPAIR KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$39.95Qty in Cart: 0Quantity:Price:$39.95Subtotal: -
PROX Water Pump Rebuild Kit - Kawasaki 57.4315
PROX
$44.95A failing water pump compromises engine cooling efficiency and risks catastrophic overheating—especially critical in high-performance or racing applications where thermal management directly impacts...09347047- SKU:
- 09347047
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- TYPE:
- WATER PUMP
- UNITS:
- KIT
- PRODUCT NAME:
- REPAIR KIT
- RIDING STYLE:
- OFF-ROAD
$44.95Qty in Cart: 0Quantity:Price:$44.95Subtotal: -
PROX Water Pump Rebuild Kit - Kawasaki 57.4317
PROX
$41.95A failing water pump compromises engine cooling efficiency and risks catastrophic overheating during high-stress riding or racing conditions. The PROX Water Pump Rebuild Kit restores OEM-level...09347049- SKU:
- 09347049
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- PRODUCT NAME:
- REPAIR KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- WATER PUMP
$41.95 -
PROX Water Pump Rebuild Kit - Kawasaki 57.4319
PROX
$44.95A failing water pump compromises engine cooling efficiency and puts your motor at risk of catastrophic overheating. The PROX Water Pump Rebuild Kit gives you OEM-equivalent components at a fraction...09347051- SKU:
- 09347051
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- REPAIR KIT
- TYPE:
- WATER PUMP
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$44.95Qty in Cart: 0Quantity:Price:$44.95Subtotal: -
PROX Water Pump Rebuild Kit - Suzuki 57.4324
PROX
$39.95A failing water pump compromises cooling system efficiency and risks catastrophic engine damage—particularly critical in high-performance and racing applications where thermal management is...09347052- SKU:
- 09347052
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- REPAIR KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- WATER PUMP
$39.95Qty in Cart: 0Quantity:Price:$39.95Subtotal:
