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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On Sale
PROX Crankshaft Bearing/Seal Kit - Husqvarna/KTM 23.CBS63016
PROX
MSRP: $180.95Now: $144.00Was: $180.95Crankshaft bearing and seal failure can compromise engine integrity and sideline your machine at critical moments. This ProX kit delivers OEM-specification components engineered for reliability,...09240706- SKU:
- 09240706
- Availability:
- Ships Same Business Day
- Weight:
- 1.20 LBS
MSRP: $180.95Now: $144.00Was: $180.95 -
On Sale
PROX Crankshaft Bearing/Seal Kit - KTM 23.CBS64007
PROX
MSRP: $169.95Now: $136.00Was: $169.95A worn crankshaft bearing or degraded seal compromises engine reliability and can lead to catastrophic damage if left unaddressed. The PROX Crankshaft Bearing/Seal Kit restores OEM-specification...09240708- SKU:
- 09240708
- Availability:
- Ships Same Business Day
- Weight:
- 0.60 LBS
MSRP: $169.95Now: $136.00Was: $169.95 -
On Sale
PROX Crankshaft Bearing/Seal Kit - Husaberg/Husqvarna/KTM 23.CBS64012
PROX
MSRP: $95.95Now: $76.00Was: $95.95A crankshaft bearing and seal kit is essential maintenance for keeping your engine reliable through demanding riding conditions. ProX's OEM-specification design ensures your crankshaft operates with...09240709- SKU:
- 09240709
- Availability:
- Ships Same Business Day
- Weight:
- 0.90 LBS
MSRP: $95.95Now: $76.00Was: $95.95 -
On Sale
PROX Crankshaft Bearing/Seal Kit - Gas-Gas/Husqvarna/KTM 23.CBS64016
PROX
MSRP: $169.95Now: $136.00Was: $169.95A crankshaft bearing and seal kit is essential maintenance for keeping your two-stroke engine running at peak performance and reliability. Over time, factory bearings wear and seals degrade, allowing...09240710- SKU:
- 09240710
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
MSRP: $169.95Now: $136.00Was: $169.95 -
On Sale
PROX Crankshaft Bearing/Seal Kit - Beta 23.CBS73013
PROX
MSRP: $73.95Now: $59.00Was: $73.95Engine longevity depends on precision bearing and seal integrity—factory-spec replacements prevent premature wear, oil leakage, and catastrophic failure. The PROX 23.CBS73013 kit delivers OEM-quality...09240711- SKU:
- 09240711
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
MSRP: $73.95Now: $59.00Was: $73.95 -
On Sale
PROX Crankshaft Bearing/Seal Kit - Beta 23.CBS73022
PROX
MSRP: $123.95Now: $99.00Was: $123.95Crankshaft bearing and seal failure doesn't just sideline your engine—it can cause catastrophic internal damage that costs thousands to repair. The PROX Crankshaft Bearing/Seal Kit (Beta 23.CBS73022)...09240712- SKU:
- 09240712
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
MSRP: $123.95Now: $99.00Was: $123.95 -
On Sale
PROX Crankshaft Bearing/Seal Kit - Beta 23.CBS73050
PROX
MSRP: $106.95Now: $85.00Was: $106.95A crankshaft bearing and seal failure can sideline your engine when you can least afford it. The PROX 23.CBS73050 kit delivers OEM-spec replacement bearings and seals manufactured to exact factory...09240713- SKU:
- 09240713
- Availability:
- Ships Same Business Day
- Weight:
- 1.36 LBS
MSRP: $106.95Now: $85.00Was: $106.95 -
On Sale
PROX Water Pump Rebuild Kit - Honda 57.1417
PROX
MSRP: $57.95Now: $47.00Was: $57.95Water pump failure can sideline your Honda when you need it most, leaving you stranded with expensive downtime and potential engine damage. The PROX 57.1417 Rebuild Kit delivers a complete,...09347755- SKU:
- 09347755
- Availability:
- Ships Same Business Day
- Weight:
- 0.18 LBS
MSRP: $57.95Now: $47.00Was: $57.95 -
On Sale
PROX Water Pump Rebuild Kit - Kawasaki 57.4327
PROX
MSRP: $57.95Now: $47.00Was: $57.95Water pump failure can sideline your Kawasaki mid-season, but a full rebuild extends component life and restores cooling system reliability without replacing the entire assembly. This PROX kit...09347756- SKU:
- 09347756
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
MSRP: $57.95Now: $47.00Was: $57.95 -
On Sale
PROX Water Pump Rebuild Kit - Husqvarna/KTM 57.6327
PROX
MSRP: $46.95Now: $38.00Was: $46.95A failing water pump doesn't just compromise cooling efficiency—it puts your entire engine at risk. The PROX Water Pump Rebuild Kit for Husqvarna and KTM machines gives you a complete, cost-effective...09347757- SKU:
- 09347757
- Availability:
- Ships Same Business Day
- Weight:
- 0.28 LBS
MSRP: $46.95Now: $38.00Was: $46.95 -
On Sale
PROX Water Pump Rebuild Kit - KTM 57.6407
PROX
MSRP: $41.95Now: $34.00Was: $41.95A failing water pump can leave you stranded mid-race or trail, compromising engine cooling when you need it most. This PROX rebuild kit restores your water pump to OEM specifications without the cost...09347758- SKU:
- 09347758
- Availability:
- Ships Same Business Day
- Weight:
- 0.19 LBS
MSRP: $41.95Now: $34.00Was: $41.95 -
On Sale
PROX Water Pump Rebuild Kit - Husqvarna/KTM 57.6416
PROX
MSRP: $67.95Now: $55.00Was: $67.95A failing water pump can spell disaster for your engine—overheating, catastrophic damage, and expensive downtime. The PROX Water Pump Rebuild Kit gives you a straightforward way to restore cooling...09347759- SKU:
- 09347759
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
MSRP: $67.95Now: $55.00Was: $67.95 -
On Sale
PROX Top End Gasket Set - Honda 35.1352
PROX
MSRP: $93.95Now: $76.00Was: $93.95A top-end rebuild demands precision sealing—any leak compromises compression and power output. The PROX 35.1352 Gasket Set delivers complete coverage for Honda applications, engineered to OEM...09347760- SKU:
- 09347760
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
MSRP: $93.95Now: $76.00Was: $93.95 -
On Sale
PROX Top End Gasket Set - Honda 35.1421
PROX
MSRP: $93.95Now: $76.00Was: $93.95A top-end rebuild demands precision sealing—any leak or gasket failure undermines engine reliability and performance. The PROX 35.1421 gasket set delivers OEM-grade sealing surfaces manufactured to...09347761- SKU:
- 09347761
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
MSRP: $93.95Now: $76.00Was: $93.95 -
On Sale
PROX Top End Gasket Set - Honda 35.1423
PROX
MSRP: $93.95Now: $76.00Was: $93.95A degraded top-end gasket set compromises compression, invites oil seepage, and forces your engine to work harder than it should. The PROX 35.1423 delivers complete sealing integrity across all...09347762- SKU:
- 09347762
- Availability:
- Ships Same Business Day
- Weight:
- 0.21 LBS
MSRP: $93.95Now: $76.00Was: $93.95 -
On Sale
PROX Top End Gasket Set - Yamaha 35.2232
PROX
MSRP: $30.95Now: $25.00Was: $30.95A top-end rebuild demands precision sealing—any leak compromises performance and invites catastrophic engine damage. The PROX 35.2232 gasket set delivers OEM-grade sealing surfaces across your entire...09347763- SKU:
- 09347763
- Availability:
- Ships Same Business Day
- Weight:
- 0.12 LBS
MSRP: $30.95Now: $25.00Was: $30.95 -
On Sale
PROX Top End Gasket Set - Yamaha 35.2450
PROX
MSRP: $72.95Now: $59.00Was: $72.95A top-end rebuild demands precision—gasket failure introduces oil leaks, compression loss, and costly engine damage. The PROX 35.2450 Top End Gasket Set delivers the complete complement of OEM-spec...09347764- SKU:
- 09347764
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
MSRP: $72.95Now: $59.00Was: $72.95 -
On Sale
PROX Top End Gasket Set - Yamaha 35.2453
PROX
MSRP: $88.95Now: $72.00Was: $88.95A top-end rebuild demands precision sealing—any leak or gasket failure compromises compression and performance. The PROX Top End Gasket Set delivers OEM-equivalent quality at a fraction of the cost,...09347765- SKU:
- 09347765
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
MSRP: $88.95Now: $72.00Was: $88.95 -
On Sale
PROX Top End Gasket Set - Suzuki 35.3349
PROX
MSRP: $72.95Now: $59.00Was: $72.95A top-end rebuild demands precision sealing—any leak or gap compromises combustion efficiency and reliability. The PROX Top End Gasket Set for Suzuki engines delivers OEM-grade sealing with ProX's...09347767- SKU:
- 09347767
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
MSRP: $72.95Now: $59.00Was: $72.95 -
On Sale
PROX Top End Gasket Set - Kawasaki 35.4350
PROX
MSRP: $78.95Now: $64.00Was: $78.95A top-end rebuild demands precision sealing—any leak compromises compression, power delivery, and engine longevity. The PROX Top End Gasket Set delivers OEM-equivalent sealing performance with...09347768- SKU:
- 09347768
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
MSRP: $78.95Now: $64.00Was: $78.95
