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
-
PROX Gasket Kit - Complete 34.6216
PROX
$126.95A quality gasket kit is the foundation of engine reliability—sealing critical surfaces that prevent oil leaks, coolant loss, and combustion blow-by that compromise performance and longevity. PROX's...09346685- SKU:
- 09346685
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- RIDING STYLE:
- STREET
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- GASKET KIT
$126.95 -
PROX Crank Seal Kit - CRF250R 42.1402
PROX
$22.95A compromised crank seal accelerates wear on your bottom end and invites contamination into critical bearing surfaces—a direct path to catastrophic engine failure. This PROX kit delivers OEM-quality...09350070- SKU:
- 09350070
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- APPLICATION:
- CRANKSHAFT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- OIL
- PRODUCT NAME:
- SEAL
$22.95 -
PROX Crank Seal Kit - YZ125 42.2225
PROX
$16.95A worn or leaking crank seal will compromise engine compression and allow contamination into your bottom end—both costly problems that compromise reliability and performance. The PROX Crank Seal Kit...09350071- SKU:
- 09350071
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- OIL
- APPLICATION:
- CRANKSHAFT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- SEAL
$16.95 -
PROX Crank Seal Kit - RM250 42.3323
PROX
$29.95A worn crankshaft seal can silently undermine engine reliability, leading to oil leakage and costly damage that sidelined racers can't afford. The PROX Crank Seal Kit RM250 delivers OEM-quality seals...09350073- SKU:
- 09350073
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- APPLICATION:
- CRANKSHAFT
- TYPE:
- OIL
- UNITS:
- KIT
- PRODUCT NAME:
- SEAL
- RIDING STYLE:
- OFF-ROAD
$29.95Qty in Cart: 0Quantity:Price:$29.95Subtotal: -
PROX Water Pump Rebuild Kit - Honda 57.1015
PROX
$54.95A failing water pump compromises engine cooling efficiency and risks catastrophic overheating—especially under high-RPM racing conditions. The PROX Water Pump Rebuild Kit restores OEM performance and...09346984- SKU:
- 09346984
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
- PRODUCT NAME:
- REPAIR KIT
$54.95Qty in Cart: 0Quantity:Price:$54.95Subtotal: -
PROX Water Pump Rebuild Kit - Honda 57.1219
PROX
$41.95A failing water pump can silently destroy your engine's thermal management, leading to overheating, head gasket failure, and catastrophic damage that costs thousands to repair. The PROX Water Pump...09346985- SKU:
- 09346985
- 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 - Honda 57.1227
PROX
$36.95A failing water pump can compromise engine cooling efficiency and lead to catastrophic overheating—especially under racing conditions or sustained high-performance driving. The PROX Water Pump...09346987- SKU:
- 09346987
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- REPAIR KIT
- TYPE:
- WATER PUMP
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
$36.95 -
PROX Water Pump Rebuild Kit - Honda 57.1319
PROX
$41.95A failing water pump compromises engine cooling efficiency and risks catastrophic overheating—especially critical under racing conditions or sustained high-performance driving. The PROX Water Pump...09346989- SKU:
- 09346989
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- REPAIR KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$41.95 -
PROX Water Pump Rebuild Kit - Honda 57.1321
PROX
$54.95A failing water pump can compromise engine cooling and lead to catastrophic overheating—especially under racing conditions or sustained high-performance driving. The PROX 57.1321 rebuild kit restores...09346990- SKU:
- 09346990
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- PRODUCT NAME:
- REPAIR KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$54.95Qty in Cart: 0Quantity:Price:$54.95Subtotal: -
PROX Water Pump Rebuild Kit - Honda 57.1322
PROX
$36.95A failing water pump can lead to catastrophic engine overheating and costly rebuilds. Rather than replacing the entire assembly, the PROX Water Pump Rebuild Kit gives you OEM-quality components at a...09346991- SKU:
- 09346991
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- PRODUCT NAME:
- REPAIR KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$36.95Qty in Cart: 0Quantity:Price:$36.95Subtotal: -
PROX Water Pump Rebuild Kit - Honda 57.1324
PROX
$36.95A failing water pump is one of the most common causes of unexpected engine damage and costly downtime. The PROX Water Pump Rebuild Kit gives you a cost-effective way to restore your Honda's cooling...09346992- SKU:
- 09346992
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- REPAIR KIT
- TYPE:
- WATER PUMP
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
$36.95 -
PROX Water Pump Rebuild Kit - Honda 57.1425
PROX
$62.95A failing water pump can quickly compromise engine cooling and lead to catastrophic overheating—especially under racing conditions or sustained high-performance driving. The PROX Water Pump Rebuild...09346995- SKU:
- 09346995
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- PRODUCT NAME:
- REPAIR KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- WATER PUMP
$62.95 -
PROX Water Pump Rebuild Kit - Honda 57.1429
PROX
$52.95Your Honda's cooling system depends on a properly functioning water pump—neglect it, and you're risking catastrophic engine failure. The PROX Water Pump Rebuild Kit gives you OEM-quality seals,...09346999- SKU:
- 09346999
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- REPAIR KIT
- TYPE:
- WATER PUMP
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$52.95 -
PROX Water Pump Rebuild Kit - Yamaha 57.2114
PROX
$36.95A failing water pump compromises engine cooling efficiency and risks catastrophic overheating during high-performance operation. The PROX Water Pump Rebuild Kit restores OEM cooling capacity with...09347004- SKU:
- 09347004
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- PRODUCT NAME:
- REPAIR KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$36.95Qty in Cart: 0Quantity:Price:$36.95Subtotal: -
PROX Water Pump Rebuild Kit - Yamaha 57.2122
PROX
$36.95A failing water pump compromises engine cooling efficiency and risks catastrophic overheating—especially critical under racing conditions or sustained high-performance driving. The PROX 57.2122...09347005- SKU:
- 09347005
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- REPAIR KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$36.95 -
PROX Water Pump Rebuild Kit - Yamaha 57.2218
PROX
$36.95A worn water pump compromises cooling efficiency and risks catastrophic engine damage—especially critical in high-performance applications where thermal management directly impacts reliability and...09347006- SKU:
- 09347006
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- WATER PUMP
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- REPAIR KIT
$36.95Qty in Cart: 0Quantity:Price:$36.95Subtotal: -
PROX Water Pump Rebuild Kit - Yamaha 57.2225
PROX
$36.95Water pump failure can leave you stranded and cause catastrophic engine damage from overheating. The PROX Water Pump Rebuild Kit gives you factory-quality internal components to restore cooling...09347007- SKU:
- 09347007
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- REPAIR KIT
- TYPE:
- WATER PUMP
- UNITS:
- KIT
$36.95 -
PROX Water Pump Rebuild Kit - Yamaha 57.2318
PROX
$44.95A failing water pump can compromise your engine's thermal stability and lead to catastrophic overheating—especially under racing conditions or extended high-load operation. The PROX Water Pump...09347009- SKU:
- 09347009
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- PRODUCT NAME:
- REPAIR KIT
- TYPE:
- WATER PUMP
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$44.95 -
PROX Water Pump Rebuild Kit - Yamaha 57.2319
PROX
$36.95A failing water pump compromises your engine's cooling efficiency, risking catastrophic overheating during high-performance operation. The PROX 57.2319 Rebuild Kit lets you restore your Yamaha water...09347010- SKU:
- 09347010
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- REPAIR KIT
- TYPE:
- WATER PUMP
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
$36.95 -
PROX Water Pump Rebuild Kit - Yamaha 57.2320
PROX
$34.95A failing water pump compromises engine cooling efficiency and risks catastrophic overheating—especially under racing conditions or sustained high-RPM operation. The PROX Water Pump Rebuild Kit for...09347011- SKU:
- 09347011
- Availability:
- Ships Same Business Day
- Weight:
- 0.03 LBS
- PRODUCT NAME:
- REPAIR KIT
- TYPE:
- WATER PUMP
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$34.95Qty in Cart: 0Quantity:Price:$34.95Subtotal:
