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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- Price
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On Sale
VINTCO Oil Seal Kit - Kawasaki KOS016
VINTCO
MSRP: $42.95Now: $39.94Was: $42.95A complete engine rebuild demands precision in every component—and oil seals are non-negotiable for preventing leaks and maintaining proper lubrication throughout your lower end. This VINTCO kit...09347352- SKU:
- 09347352
- Availability:
- Ships Same Business Day
- Weight:
- 0.21 LBS
MSRP: $42.95Now: $39.94Was: $42.95 -
On Sale
VINTCO Oil Seal Kit - Kawasaki KOS012
VINTCO
MSRP: $42.95Now: $39.94Was: $42.95A complete engine rebuild demands precision sealing—any leak in your crankshaft, kickstarter, or clutch release shaft can compromise performance and reliability. The VINTCO Oil Seal Kit KOS012...09347353- SKU:
- 09347353
- Availability:
- Ships Same Business Day
- Weight:
- 0.16 LBS
MSRP: $42.95Now: $39.94Was: $42.95 -
On Sale
VINTCO Oil Seal Kit - Honda KOS002
VINTCO
MSRP: $27.95Now: $25.99Was: $27.95A complete engine rebuild demands precision at every junction—and oil seals are where catastrophic leaks begin. The VINTCO Oil Seal Kit (KOS002) supplies all critical seals and o-rings for Honda...09347354- SKU:
- 09347354
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
MSRP: $27.95Now: $25.99Was: $27.95 -
On Sale
VINTCO Oil Seal Kit - Kawasaki KOS014
VINTCO
MSRP: $42.95Now: $39.94Was: $42.95A complete engine rebuild demands precision sealing throughout the lower end—neglecting this step invites oil leakage, contamination, and premature wear on critical components. The VINTCO Oil Seal...09347355- SKU:
- 09347355
- Availability:
- Ships Same Business Day
- Weight:
- 0.06 LBS
MSRP: $42.95Now: $39.94Was: $42.95 -
On Sale
VINTCO Oil Seal Kit - Honda KOS003
VINTCO
MSRP: $27.95Now: $25.99Was: $27.95A complete engine rebuild demands precision sealing—any leak in your lower end will compromise compression and invite contamination into your oil system. This comprehensive seal kit eliminates the...09347358- SKU:
- 09347358
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
MSRP: $27.95Now: $25.99Was: $27.95 -
On Sale
VINTCO Oil Seal Kit - Kawasaki KOS015
VINTCO
MSRP: $42.95Now: $39.94Was: $42.95A complete engine rebuild demands precision at every seal point—and this VINTCO Oil Seal Kit eliminates the guesswork by bundling all the critical seals your Kawasaki engine needs in one package...09347359- SKU:
- 09347359
- Availability:
- Ships Same Business Day
- Weight:
- 0.16 LBS
MSRP: $42.95Now: $39.94Was: $42.95 -
On Sale
VINTCO Oil Seal Kit - Kawasaki KOS013
VINTCO
MSRP: $39.95Now: $37.15Was: $39.95A complete engine rebuild demands precision sealing to prevent oil leakage and maintain proper lubrication throughout your lower end. This VINTCO Oil Seal Kit delivers OEM-grade seals and o-rings...09347361- SKU:
- 09347361
- Availability:
- Ships Same Business Day
- Weight:
- 0.16 LBS
MSRP: $39.95Now: $37.15Was: $39.95 -
Hinson Racing Clutch Cover Kawasaki KX450 2021-2023 C663-2102
HINSON RACING
$169.99Stock clutch covers on the KX450 will warp and lose efficiency under sustained track temperatures. This Hinson Racing cover dissipates heat more effectively, keeping your clutch engagement consistent...09402038- SKU:
- 09402038
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
$169.99 -
HOT RODS Crankshaft Assembly - OEM Stroke - Gas Gas | Husqvarna | KTM HR00125
HOT RODS
$531.95A crankshaft assembly is the heart of your engine's bottom end—it converts combustion force into rotational power. Hot Rods delivers OEM-stroke precision without compromise, factory-assembled and...09210923- SKU:
- 09210923
- Availability:
- Ships Same Business Day
- Weight:
- 8.75 LBS
$531.95 -
On Sale
WISECO Piston Kit - 54.00 mm - Yamaha 899M05400
WISECO
MSRP: $155.95Now: $110.00Was: $155.95Stock pistons can't handle the demands of serious 2-stroke riding—they compromise on durability, throttle response, and peak horsepower. The WISECO 54.00 mm Piston Kit delivers a purpose-built...09106456- SKU:
- 09106456
- Availability:
- Ships Same Business Day
- Weight:
- 0.46 LBS
MSRP: $155.95Now: $110.00Was: $155.95 -
On Sale
Wiseco Piston Kit 54.00 mm Yamaha YZ125 2005-2021 846M05400
WISECO
MSRP: $199.95Now: $149.00Was: $199.95Stock pistons can't handle the demands of high-RPM riding or extended racing seasons—wear, carbon buildup, and power loss follow. The Wiseco 54.00 mm Piston Kit for your Yamaha YZ125 (2005-2021)...09106458- SKU:
- 09106458
- Availability:
- Ships Same Business Day
- Weight:
- 0.36 LBS
MSRP: $199.95Now: $149.00Was: $199.95 -
MOOSE RACING Snap Ring - 10 Pack - Gas Gas/Husqvarna/KTM 25-6014
MOOSE RACING
$24.95Front sprocket replacements demand precision fastening—and countershaft snap rings are easy to overlook until you need them. Keep this 10-pack of MOOSE Racing snap rings in your pit box or garage to...09351211- SKU:
- 09351211
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
$24.95 -
MOOSE RACING Countershaft Washer - 10 Pack - Kawasaki/Yamaha 25-6018
MOOSE RACING
$30.95Front sprocket replacements demand precision fitment, and overlooking the countershaft washer is a costly mistake that leads to improper bearing preload and premature wear. This 10-pack from MOOSE...09351212- SKU:
- 09351212
- Availability:
- Ships Same Business Day
- Weight:
- 0.26 LBS
$30.95 -
MOOSE RACING Piston Kit - 77.00 mm - Kawasaki MPX3050C
MOOSE RACING
$326.95When you're pushing your Kawasaki MPX3050C to the limit, factory pistons won't cut it. MOOSE Racing delivers a fully-forged piston kit engineered to handle extreme combustion pressures while shedding...09106491- SKU:
- 09106491
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
$326.95 -
MOOSE RACING Piston Kit - 77.00 mm - Yamaha MPX1090C
MOOSE RACING
$386.95Stock pistons are a limiting factor in any serious build—they fail under sustained high RPM, generate excessive heat, and rob you of power. MOOSE Racing's forged piston kit delivers the durability...09106494- SKU:
- 09106494
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
$386.95 -
MOOSE RACING Piston Kit - 96.00 mm - Kawasaki MPX3036
MOOSE RACING
$386.95A high-performance piston kit is critical for maintaining reliability and maximizing power output in high-RPM applications. The MOOSE RACING MPX3036 delivers the strength and precision engineering...09106498- SKU:
- 09106498
- Availability:
- Ships Same Business Day
- Weight:
- 1.16 LBS
$386.95 -
MOOSE RACING Piston Kit - 78.00 mm - Husqvarna | KTM MPX9060C-P
MOOSE RACING
$471.95A piston kit is the heart of your engine's power delivery—when it fails, performance and reliability suffer dramatically. This MOOSE Racing 78mm piston kit is engineered to handle extreme combustion...09106499- SKU:
- 09106499
- Availability:
- Ships Same Business Day
- Weight:
- 0.81 LBS
$471.95 -
MOOSE RACING Piston Kit - 95.00 mm - Husqvarna MPX9061-P
MOOSE RACING
$471.95When you're pushing your Husqvarna to its limits, piston durability becomes non-negotiable. This MOOSE Racing kit eliminates the weak points that cause failure under sustained high RPM and combustion...09106500- SKU:
- 09106500
- Availability:
- Ships Same Business Day
- Weight:
- 1.11 LBS
$471.95 -
MOOSE RACING Piston Kit - 77.00 mm - Kawasaki MPX3061
MOOSE RACING
$386.95If you're pushing your Kawasaki to the limit, a worn or marginal piston kit will cost you power, reliability, and ultimately race results. The MOOSE RACING 77.00 mm Piston Kit is engineered to...09106501- SKU:
- 09106501
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
$386.95 -
MOOSE RACING Piston Kit - 96.00 mm - Honda MPX2180
MOOSE RACING
$386.95If you're building or rebuilding a high-revving Honda engine, piston durability and thermal stability are non-negotiable. This MOOSE RACING kit delivers the strength and precision needed to handle...09106502- SKU:
- 09106502
- Availability:
- Ships Same Business Day
- Weight:
- 1.11 LBS
$386.95
