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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- Qty in Cart
- Quantity
- Price
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On Sale
PROX Crankshaft Oil Seal Set - Beta 42.7350
PROX
MSRP: $30.95Now: $25.00Was: $30.95A compromised crankshaft seal can lead to catastrophic oil loss and engine damage—especially under high RPM conditions where pressure spikes expose even minor leaks. The PROX Crankshaft Oil Seal Set keeps oil where it belongs: inside the engine. This...09351281- SKU:
- 09351281
- Availability:
- Ships Same Business Day
- Weight:
- 0.06 LBS
MSRP: $30.95Now: $25.00Was: $30.95 -
On Sale
PROX Connecting Rod Kit - Honda 03.1363
PROX
MSRP: $173.95Now: $141.00Was: $173.95A connecting rod kit is critical infrastructure for any high-performance Honda engine build—it directly transfers combustion forces from the piston to the crankshaft, making durability and precision non-negotiable. The PROX 03.1363 is engineered to OEM...09230694- SKU:
- 09230694
- Availability:
- Ships Same Business Day
- Weight:
- 1.20 LBS
MSRP: $173.95Now: $141.00Was: $173.95 -
On Sale
PROX Connecting Rod Kit - Yamaha 03.2018
PROX
MSRP: $118.95Now: $93.00Was: $118.95A connecting rod failure mid-race or mid-rebuild can derail your entire engine program. The PROX Connecting Rod Kit for Yamaha engines delivers the dimensional precision and material strength needed to handle sustained high RPM loads without compromise...09230695- SKU:
- 09230695
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
MSRP: $118.95Now: $93.00Was: $118.95 -
On Sale
PROX Connecting Rod Kit - Yamaha 03.2232
PROX
MSRP: $132.95Now: $102.00Was: $132.95A connecting rod kit is critical for maintaining engine integrity and performance—it directly transfers combustion forces from your pistons to the crankshaft, and a worn or damaged rod can cause catastrophic engine failure. The PROX 03.2232 is engineered...09230696- SKU:
- 09230696
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
MSRP: $132.95Now: $102.00Was: $132.95 -
On Sale
PROX Connecting Rod Kit - Gas Gas | Yamaha 03.2432
PROX
MSRP: $183.95Now: $150.00Was: $183.95A connecting rod is critical to engine reliability—it directly transfers combustion force from the piston to the crankshaft under extreme stress and temperature. PROX's double-forged construction maintains superior grain flow, ensuring dimensional...09230697- SKU:
- 09230697
- Availability:
- Ships Same Business Day
- Weight:
- 1.35 LBS
MSRP: $183.95Now: $150.00Was: $183.95 -
On Sale
PROX Connecting Rod Kit - Husaberg | Husqvarna | KTM 03.6333
PROX
MSRP: $232.95Now: $195.00Was: $232.95A connecting rod is the critical link between your piston and crankshaft—any weakness here directly impacts power delivery, reliability, and engine longevity. The PROX Connecting Rod Kit for Husaberg, Husqvarna, and KTM engines is manufactured to exact...09230699- SKU:
- 09230699
- Availability:
- Ships Same Business Day
- Weight:
- 1.20 LBS
MSRP: $232.95Now: $195.00Was: $232.95 -
On Sale
PROX Connecting Rod Kit - Beta 03.7322
PROX
MSRP: $137.95Now: $110.00Was: $137.95A connecting rod is the critical link between your piston and crankshaft—any weakness here directly compromises power delivery and engine reliability. The PROX Connecting Rod Kit is engineered to OEM specifications with double-forged construction that...09230702- SKU:
- 09230702
- Availability:
- Ships Same Business Day
- Weight:
- 1.11 LBS
MSRP: $137.95Now: $110.00Was: $137.95Qty in Cart: 0Quantity:Price:MSRP: $137.95Now: $110.00Was: $137.95Subtotal: -
On Sale
PROX Crankshaft Bearing/Seal Kit - Honda 23.CBS14005
PROX
MSRP: $138.95Now: $110.00Was: $138.95A worn crankshaft bearing or compromised seal will rapidly degrade engine performance and reliability. This ProX kit replaces all critical bearing and seal components in one complete package, eliminating the need to source parts individually and ensuring...09240701- SKU:
- 09240701
- Availability:
- Ships Same Business Day
- Weight:
- 1.15 LBS
MSRP: $138.95Now: $110.00Was: $138.95 -
On Sale
PROX Crankshaft Bearing/Seal Kit - Kawasaki 23.CBS43051
PROX
MSRP: $106.95Now: $85.00Was: $106.95A crankshaft bearing and seal failure can sideline your engine and compromise reliability when you need it most. This PROX kit delivers OEM-specification components engineered to restore your Kawasaki's crankshaft integrity, ensuring proper oil...09240702- SKU:
- 09240702
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
MSRP: $106.95Now: $85.00Was: $106.95 -
On Sale
PROX Crankshaft Bearing/Seal Kit - KTM 23.CBS60001
PROX
MSRP: $38.95Now: $31.00Was: $38.95A properly sealed crankshaft is fundamental to engine longevity—compromised bearings and worn seals lead to oil starvation and contamination that cascade into catastrophic failure. This ProX kit delivers OEM-specification bearings and seals engineered to...09240703- SKU:
- 09240703
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
MSRP: $38.95Now: $31.00Was: $38.95 -
On Sale
PROX Crankshaft Bearing/Seal Kit - KTM 23.CBS60009
PROX
MSRP: $41.95Now: $34.00Was: $41.95A worn or damaged crankshaft bearing and seal assembly will compromise engine integrity, reduce performance, and risk catastrophic failure. The PROX Crankshaft Bearing/Seal Kit delivers OEM-specification replacement components that restore proper...09240704- SKU:
- 09240704
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
MSRP: $41.95Now: $34.00Was: $41.95 -
On Sale
PROX Crankshaft Bearing/Seal Kit - Husaberg/Husqvarna/KTM 23.CBS63013
PROX
MSRP: $187.95Now: $150.00Was: $187.95A compromised crankshaft bearing or seal will quickly degrade engine performance and lead to catastrophic internal damage. The PROX Crankshaft Bearing/Seal Kit supplies all necessary components to restore your crankshaft to OEM specifications, ensuring...09240705- SKU:
- 09240705
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
MSRP: $187.95Now: $150.00Was: $187.95 -
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, ensuring your crankshaft operates with minimal friction and...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 performance with factory-engineered components, ensuring...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 minimal friction and maximum protection against...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 oil leakage and contamination that compromise...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 components at a fraction of dealer pricing, ideal for...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) restores your crankshaft assembly to OEM...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 tolerances, ensuring your crankshaft assembly maintains...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, cost-effective solution to restore your pump to factory...09347755- SKU:
- 09347755
- Availability:
- Ships Same Business Day
- Weight:
- 0.18 LBS
MSRP: $57.95Now: $47.00Was: $57.95
