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
-
TMV Flywheel Weight 310FW2211
TMV
$152.95A heavier flywheel stabilizes engine rpm, reduces rev hang, and delivers smoother power delivery—critical for track applications where consistent throttle response separates winning runs from average...09220100- SKU:
- 09220100
- Availability:
- Ships Same Business Day
- Weight:
- 0.95 LBS
- FEATURES:
- FLYWHEEL WEIGHT - 11 OZ.
- MATERIAL:
- 303 STAINLESS STEEL
- PRODUCT NAME:
- FLYWHEEL WEIGHT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$152.95Qty in Cart: 0Quantity:Price:$152.95Subtotal: -
TMV Flywheel Weight 310FW3113
TMV
$152.95A heavier flywheel stores more rotational energy, delivering superior engine responsiveness and smoother power delivery across the RPM band. The TMV 310FW3113 achieves this performance gain through...09220108- SKU:
- 09220108
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- PRODUCT NAME:
- FLYWHEEL WEIGHT
- FEATURES:
- FLYWHEEL WEIGHT - 13 OZ.
- RIDING STYLE:
- OFF-ROAD
- MATERIAL:
- 303 STAINLESS STEEL
- UNITS:
- EACH
$152.95Qty in Cart: 0Quantity:Price:$152.95Subtotal: -
MOOSE RACING Inner Clutch Cover Gasket 816213
MOOSE RACING
$13.18A leaking clutch cover gasket compromises engine sealing and invites oil loss—replacing it is essential maintenance for any rebuild or repair. This Moose Racing gasket delivers OEM-equivalent fitment...09346127- SKU:
- 09346127
- Availability:
- Ships Same Business Day
- Weight:
- 0.16 LBS
- PRODUCT NAME:
- GASKET
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH COVER
$13.18 -
MOOSE RACING Clutch Cover Gasket 817826
MOOSE RACING
$8.88A leaking clutch cover gasket compromises engine reliability and creates messy maintenance headaches. The Moose Racing 817826 replacement gasket seals with precision while withstanding thermal...09341460- SKU:
- 09341460
- Availability:
- Ships Same Business Day
- Weight:
- 0.04 LBS
- PRODUCT NAME:
- GASKET
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH COVER
$8.88 -
MOOSE RACING Crankcase Bearing and Seal Kit 24-1027
MOOSE RACING
$89.95A worn crankshaft bearing or degraded seal can introduce metal-to-metal contact, excessive drag, and catastrophic engine failure—especially critical in high-RPM 2-stroke applications. The MOOSE...A241027- SKU:
- A241027
- Availability:
- Ships Same Business Day
- Weight:
- 1.40 LBS
- TYPE:
- CRANK
- PRODUCT NAME:
- BEARING KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$89.95 -
MOOSE RACING Valve Kit M30-32285
MOOSE RACING
$259.95Factory valve sets are engineered with a specific purpose: deliver consistent performance within OE tolerances. The MOOSE RACING M30-32285 Valve Kit replaces worn or damaged valves while maintaining...09262579- SKU:
- 09262579
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- MATERIAL:
- TITANIUM
- MODEL:
- PRO
- UNITS:
- KIT
- APPLICATION:
- EXHAUST
- MATERIAL:
- STAINLESS STEEL
- APPLICATION:
- INTAKE
- PRODUCT NAME:
- VALVE KIT
- RIDING STYLE:
- OFF-ROAD
$259.95Qty in Cart: 0Quantity:Price:$259.95Subtotal: -
MOOSE RACING Cylinder - Standard - KX85 MSE30009
MOOSE RACING
$543.95If your KX85 has suffered cylinder damage or excessive wear, a factory-spec replacement is essential to restore compression, ring sealing, and overall engine performance. The MOOSE RACING cylinder...09310623- SKU:
- 09310623
- Availability:
- Ships Same Business Day
- Weight:
- 3.55 LBS
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- MATERIAL:
- ALUMINUM
- PRODUCT NAME:
- CYLINDER
- RIDING STYLE:
- OFF-ROAD
- MATERIAL:
- CAST
- UNITS:
- EACH
$543.95Qty in Cart: 0Quantity:Price:$543.95Subtotal: -
MOOSE RACING Motor Gasket Kit with Seal - RMZ/KXF 811463
MOOSE RACING
$155.07A complete engine and transmission rebuild demands precision gaskets and seals that won't compromise your work or your wallet. This Moose Racing kit eliminates the hassle of sourcing individual...09341480- SKU:
- 09341480
- Availability:
- Ships Same Business Day
- Weight:
- 0.42 LBS
$155.07Qty in Cart: 0Quantity:Price:$155.07Subtotal: -
MOOSE RACING Motor Gasket Kit with Seal - 300SX/EXC 811326
MOOSE RACING
$54.94A complete engine and transmission rebuild demands precision gaskets and seals that won't compromise your work or your wallet. The MOOSE RACING Motor Gasket Kit delivers OEM-quality replacement seals...09340482- SKU:
- 09340482
- Availability:
- Ships Same Business Day
- Weight:
- 0.17 LBS
$54.94Qty in Cart: 0Quantity:Price:$54.94Subtotal: -
MOOSE RACING Complete Motor Gasket Kit - CRF450X 808276
MOOSE RACING
$200.16A complete engine and transmission rebuild demands precision gasket fit and material reliability—shortcuts here lead to leaks, compression loss, and costly downtime. The MOOSE RACING Complete Motor...09340969- SKU:
- 09340969
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- TYPE:
- COMPLETE
- TYPE:
- ENGINE
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$200.16Qty in Cart: 0Quantity:Price:$200.16Subtotal: -
MOOSE RACING Valve Shim - 9.48 x 2.75 - 5 pack MSE5PK948275
MOOSE RACING
$10.95Valve shim maintenance is critical to engine longevity and performance—improper shimming leads to valve clearance issues, lost compression, and catastrophic engine damage. The MOOSE RACING 9.48 x 2...09261959- SKU:
- 09261959
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- VALVE SHIM THICKNESS METRIC:
- 2.75 MM
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- SNOW
- UNITS:
- 5 PACK
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
$10.95 -
MOOSE RACING Valve Shim - 9.48 x 2.80 - 5 pack MSE5PK948280
MOOSE RACING
$10.95Precision valve train maintenance demands reliable, clearly-identified shims that won't let you down mid-rebuild. These MOOSE RACING shims eliminate guesswork with laser-etched sizing and forged 4140...09261960- SKU:
- 09261960
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- VALVE SHIM THICKNESS METRIC:
- 2.80 MM
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- SNOW
- UNITS:
- 5 PACK
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
$10.95 -
MOOSE RACING Valve Shim - 10.0 x 2.40 - 5 pack MSE5PK1000240
MOOSE RACING
$10.95Proper valve shim selection is critical for maintaining accurate valve clearances and preventing premature wear on your valve train. These MOOSE RACING shims are forged from 4140 cold-rolled...09261841- SKU:
- 09261841
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- VALVE SHIM THICKNESS METRIC:
- 2.40 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- VALVE
$10.95Qty in Cart: 0Quantity:Price:$10.95Subtotal: -
MOOSE RACING Valve Shim - 10.0 x 2.50 - 5 pack MSE5PK1000250
MOOSE RACING
$10.95Maintaining precise valve clearances is critical to engine performance and longevity, and having quality shims on hand eliminates downtime during valve train service. MOOSE Racing valve shims are...09261843- SKU:
- 09261843
- Availability:
- Ships Same Business Day
- Weight:
- 0.01 LBS
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- VALVE SHIM THICKNESS METRIC:
- 2.50 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- STREET
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- UNITS:
- 5 PACK
$10.95Qty in Cart: 0Quantity:Price:$10.95Subtotal: -
MOOSE RACING Valve Shim - 10.0 x 2.70 - 5 pack MSE5PK1000270
MOOSE RACING
$10.95Valve shim maintenance is critical for precise valve train geometry and consistent performance across rebuild cycles. These MOOSE RACING shims eliminate guesswork with laser-etched sizing, allowing...09261847- SKU:
- 09261847
- Availability:
- Ships Same Business Day
- Weight:
- 0.01 LBS
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.70 MM
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- VALVE
- UNITS:
- 5 PACK
$10.95Qty in Cart: 0Quantity:Price:$10.95Subtotal: -
MOOSE RACING Top End Gasket Kit - Yamaha 810691
MOOSE RACING
$64.22A top-end rebuild demands precision gaskets and seals that won't compromise your engine's integrity or your wallet. The MOOSE RACING Top End Gasket Kit delivers OEM-quality components at a fraction...09344776- SKU:
- 09344776
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- TYPE:
- TOP END
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
$64.22Qty in Cart: 0Quantity:Price:$64.22Subtotal: -
MOOSE RACING Complete Motor Gasket Kit - XR650L 808281
MOOSE RACING
$121.92A complete engine and transmission rebuild demands precision gaskets and seals that won't compromise your work. The Moose Racing Complete Motor Gasket Kit eliminates the frustration of sourcing...M808281- SKU:
- M808281
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- PRODUCT NAME:
- GASKET
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- TYPE:
- ENGINE
$121.92 -
MOOSE RACING Clutch Cover Gasket 817417
MOOSE RACING
$13.81A leaking clutch cover gasket compromises engine integrity and creates messy cleanup jobs that cut into your track time. The MOOSE RACING Clutch Cover Gasket delivers OEM-equivalent sealing...09346572- SKU:
- 09346572
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- GASKET
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- CLUTCH COVER
$13.81Qty in Cart: 0Quantity:Price:$13.81Subtotal: -
MOOSE RACING Ignition Cover Gasket 817416
MOOSE RACING
$14.09A leaking ignition cover gasket compromises engine sealing and can lead to oil seepage that fouls electrical connections and accelerates wear on surrounding components. The MOOSE RACING Ignition...09346573- SKU:
- 09346573
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- PRODUCT NAME:
- GASKET
- TYPE:
- IGNITION COVER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$14.09Qty in Cart: 0Quantity:Price:$14.09Subtotal: -
MOOSE RACING Inner Clutch Cover Gasket 816765
MOOSE RACING
$6.89A leaking clutch cover gasket compromises engine sealing and risks oil contamination of your clutch system—precision matters here. MOOSE Racing's inner clutch cover gasket delivers OEM-quality...09346574- SKU:
- 09346574
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET
- UNITS:
- EACH
- MOUNTING POSITION:
- INNER
- TYPE:
- CLUTCH COVER
$6.89Qty in Cart: 0Quantity:Price:$6.89Subtotal:
