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
- Subtotal
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On Sale
KIBBLEWHITE Valve - Exhaust - White Diamond 40-41616H
KIBBLEWHITE
MSRP: $35.22Now: $27.91Was: $35.22Exhaust valve performance directly impacts your engine's scavenging efficiency, combustion temperature stability, and overall power delivery. Kibblewhite's White Diamond exhaust valves are...09263388- SKU:
- 09263388
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
MSRP: $35.22Now: $27.91Was: $35.22 -
On Sale
KIBBLEWHITE Valve - Exhaust - Tensilite 40-41616T
KIBBLEWHITE
MSRP: $92.51Now: $83.26Was: $92.51Exhaust valves are critical to your engine's efficiency and longevity—especially under high RPM conditions where standard steel valves struggle with heat stress and wear. Kibblewhite's Tensilite...09263390- SKU:
- 09263390
- Availability:
- Ships Same Business Day
- Weight:
- 0.21 LBS
MSRP: $92.51Now: $83.26Was: $92.51 -
On Sale
KIBBLEWHITE Valve Guide - Intake - Standard 40-41620
KIBBLEWHITE
MSRP: $24.89Now: $22.40Was: $24.89Valve guides are critical to your engine's longevity and performance—they maintain proper valve alignment, reduce oil consumption, and prevent wear that can lead to catastrophic engine failure...09263391- SKU:
- 09263391
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
MSRP: $24.89Now: $22.40Was: $24.89 -
On Sale
KIBBLEWHITE Valve Guide - Intake - +0.010" 40-41629
KIBBLEWHITE
MSRP: $22.95Now: $20.66Was: $22.95Valve guides wear faster than most engine components, especially under sustained high-RPM operation or boost pressure. A worn intake valve guide introduces excessive valve-to-seat play, killing...09263392- SKU:
- 09263392
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
MSRP: $22.95Now: $20.66Was: $22.95 -
On Sale
KIBBLEWHITE Valve Guide - Exhaust - Standard 40-41630
KIBBLEWHITE
MSRP: $24.89Now: $22.40Was: $24.89Exhaust valve guides are critical wear points in any high-performance engine, and inadequate materials lead to excessive clearance, oil consumption, and compromised sealing. The KIBBLEWHITE Valve...09263393- SKU:
- 09263393
- Availability:
- Ships Same Business Day
- Weight:
- 0.26 LBS
MSRP: $24.89Now: $22.40Was: $24.89 -
On Sale
KIBBLEWHITE Valve Guide - Exhaust - +0.010" 40-41639
KIBBLEWHITE
MSRP: $22.95Now: $20.66Was: $22.95Exhaust valve guides are critical wear components that endure extreme temperatures and constant thermal cycling—choosing the right material makes the difference between a guide that lasts and one...09263394- SKU:
- 09263394
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
MSRP: $22.95Now: $20.66Was: $22.95 -
HOT RODS Bottom End Kit - OE Crankshaft Replacement - Polaris HR00106
HOT RODS
$1,671.55A complete bottom-end rebuild demands precision components and comprehensive gasket coverage—this kit eliminates the guesswork by bundling everything you need for a professional crankshaft...09210890- SKU:
- 09210890
- Availability:
- Ships Same Business Day
- Weight:
- 27.80 LBS
$1,671.55 -
HOT RODS Bottom End Kit - OE Crankshaft Replacement - Polaris HR00107
HOT RODS
$1,671.55A complete bottom-end rebuild demands precision components and comprehensive gasket coverage—this kit eliminates sourcing individual parts and ensures compatibility across all critical sealing...09210891- SKU:
- 09210891
- Availability:
- Ships Same Business Day
- Weight:
- 27.90 LBS
$1,671.55 -
HOT RODS Bottom End Kit - OE Crankshaft Replacement - Polaris HR00118
HOT RODS
$1,671.55A bottom-end rebuild requires precision components and complete gasket coverage—cutting corners here compromises engine reliability and longevity. The HOT RODS Bottom End Kit eliminates guesswork by...09210897- SKU:
- 09210897
- Availability:
- Ships Same Business Day
- Weight:
- 24.30 LBS
$1,671.55 -
Cylinder Works 66.4mm Cylinder for Yamaha YZ250 1999-2025 20009
CYLINDER WORKS
$645.95If you're running a Yamaha YZ250 and want measurable gains in power and torque without engine teardown complexity, a big-bore cylinder is one of the most direct upgrades available. The Cylinder Works...09311078- SKU:
- 09311078
- Availability:
- Ships Same Business Day
- Weight:
- 6.06 LBS
$645.95 -
MOOSE OFFROAD Cam Chain - DID25 x 82 Links MSEHCDID25082
MOOSE OFFROAD
$21.07A worn or damaged cam chain compromises valve timing precision, leading to power loss, poor fuel economy, and potential engine damage. The MOOSE OFFROAD DID25 x 82 Links cam chain delivers...09251421- SKU:
- 09251421
- Availability:
- Ships Same Business Day
- Weight:
- 0.26 LBS
$21.07 -
MOOSE OFFROAD Cam Chain - DID25H x 100 Links MSEHCDID25H100
MOOSE OFFROAD
$53.95A worn or damaged cam chain compromises valve timing precision and can lead to catastrophic engine failure—making a quality replacement essential for any rebuild or high-mileage engine refresh. The...09251423- SKU:
- 09251423
- Availability:
- Ships Same Business Day
- Weight:
- 0.31 LBS
$53.95 -
MOOSE OFFROAD Cam Chain - DID25H x 90 Links MSEHCDID25H090
MOOSE OFFROAD
$41.07A worn or damaged cam chain directly compromises valve timing and engine reliability—especially critical in high-performance applications where precision matters. The MOOSE OFFROAD DID25H cam chain...09251424- SKU:
- 09251424
- Availability:
- Ships Same Business Day
- Weight:
- 0.26 LBS
$41.07 -
MOOSE OFFROAD Cam Chain - 92RH2015 x 96 Links MSEHC92RH2015096
MOOSE OFFROAD
$50.95A reliable cam chain is fundamental to engine timing precision and longevity—especially in high-performance builds where tolerances matter. The MOOSE OFFROAD 92RH2015 x 96 Links cam chain delivers...09251425- SKU:
- 09251425
- Availability:
- Ships Same Business Day
- Weight:
- 0.51 LBS
$50.95 -
MOOSE OFFROAD Cam Chain - 92RH2005 x 104 Links MSEHC92RH2005104
MOOSE OFFROAD
$45.07A worn or damaged cam chain compromises valve timing precision and can lead to catastrophic engine damage if left unchecked. The MOOSE OFFROAD Cam Chain delivers OEM-equivalent reliability with...09251426- SKU:
- 09251426
- Availability:
- Ships Same Business Day
- Weight:
- 0.26 LBS
$45.07 -
MOOSE OFFROAD Cam Chain - 96RH2015 x108 Links MSEHC96RH2015108
MOOSE OFFROAD
$59.07A worn or damaged cam chain compromises valve timing precision and can lead to catastrophic engine failure. The MOOSE OFFROAD Cam Chain 96RH2015 x108 delivers OEM-grade reliability with shot-peened...09251427- SKU:
- 09251427
- Availability:
- Ships Same Business Day
- Weight:
- 0.56 LBS
$59.07 -
MOOSE OFFROAD Cam Chain - 82RH2010 x 118 Links MSEHC82RH2010118
MOOSE OFFROAD
$83.07A worn or damaged cam chain compromises valve timing precision, leading to power loss, increased wear on critical engine components, and potential catastrophic engine failure. The MOOSE OFFROAD Cam...09251428- SKU:
- 09251428
- Availability:
- Ships Same Business Day
- Weight:
- 0.46 LBS
$83.07 -
MOOSE OFFROAD Cam Chain - 92RH2015 x 114 Links MSEHC92RH2015114
MOOSE OFFROAD
$54.00A worn or compromised cam chain directly impacts valve timing accuracy and engine reliability—two non-negotiables for performance and longevity. The MOOSE OFFROAD Cam Chain delivers OEM-exceeding...09251429- SKU:
- 09251429
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
$54.00 -
MOOSE OFFROAD Cam Chain - 98XRH2015 x 112 Links MSEHC98XRH2015112
MOOSE OFFROAD
$102.95A worn or damaged cam chain compromises valve timing precision and can lead to catastrophic engine failure. The MOOSE OFFROAD Cam Chain 98XRH2015 x 112 Links delivers OEM-equivalent performance with...09251430- SKU:
- 09251430
- Availability:
- Ships Same Business Day
- Weight:
- 0.56 LBS
$102.95Qty in Cart: 0Quantity:Price:$102.95Subtotal: -
MOOSE OFFROAD Cam Chain - 92RH2015 x 110 Links MSEHC92RH2015110
MOOSE OFFROAD
$69.95A worn or damaged cam chain compromises valve timing precision, leading to performance loss, increased engine noise, and potential catastrophic damage. The MOOSE OFFROAD Cam Chain delivers...09251431- SKU:
- 09251431
- Availability:
- Ships Same Business Day
- Weight:
- 0.56 LBS
$69.95Qty in Cart: 0Quantity:Price:$69.95Subtotal:
