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
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MOOSE RACING Motor Gasket Kit with Seal - CRF450 811284
MOOSE RACING
$221.09A complete engine and transmission rebuild demands precision-fit gaskets and seals—anything less risks oil leakage, compression loss, and costly downtime. The MOOSE RACING Motor Gasket Kit delivers OEM-equivalent sealing performance at a fraction of OEM...09341889- SKU:
- 09341889
- Availability:
- Ships Same Business Day
- Weight:
- 0.46 LBS
- PRODUCT NAME:
- GASKET
- UNITS:
- KIT
- TYPE:
- ENGINE
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
$221.09 -
MOOSE RACING Top End Gasket Kit - KX250F 810481
MOOSE RACING
$90.07A top-end rebuild demands precision gaskets and seals that won't compromise your engine's integrity—especially when you're pushing performance limits. This Moose Racing kit delivers OEM-quality components at a fraction of the cost, giving you the...09341890- SKU:
- 09341890
- Availability:
- Ships Same Business Day
- Weight:
- 0.14 LBS
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET
- UNITS:
- KIT
- TYPE:
- TOP END
$90.07 -
MOOSE RACING Complete Motor Gasket Kit - KX250F 808481
MOOSE RACING
$140.62A complete engine and transmission rebuild demands precision-fit gaskets and seals—factory tolerances won't tolerate improvisation. The MOOSE RACING Complete Motor Gasket Kit eliminates the guesswork by bundling every gasket, O-ring, and valve seal...09341891- SKU:
- 09341891
- Availability:
- Ships Same Business Day
- Weight:
- 0.26 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
- TYPE:
- ENGINE
- PRODUCT NAME:
- GASKET
$140.62 -
MOOSE RACING Motor Gasket Kit with Seal - KX250F 811481
MOOSE RACING
$193.69A complete engine and transmission rebuild demands precision-fit gaskets and seals that won't compromise your work or your wallet. MOOSE Racing delivers OEM-quality replacement seals at a fraction of dealer pricing, letting you rebuild with confidence...09341892- SKU:
- 09341892
- Availability:
- Ships Same Business Day
- Weight:
- 0.43 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
- TYPE:
- ENGINE
- PRODUCT NAME:
- GASKET
$193.69 -
MOOSE RACING Top End Gasket Kit - KX450F 810482
MOOSE RACING
$88.86When you're rebuilding a KX450F top end, gasket quality directly impacts ring seal, combustion chamber integrity, and overall engine longevity. The MOOSE RACING Top End Gasket Kit eliminates the guesswork with a complete, domestically-manufactured set...09341893- SKU:
- 09341893
- Availability:
- Ships Same Business Day
- Weight:
- 0.18 LBS
- PRODUCT NAME:
- GASKET
- TYPE:
- TOP END
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$88.86 -
MOOSE RACING Complete Motor Gasket Kit - KX450F 808482
MOOSE RACING
$172.14A complete engine and transmission rebuild demands gasket and seal components that match OEM specifications without the OEM price tag. This Moose Racing kit eliminates the guesswork of sourcing individual gaskets, o-rings, and valve seals—everything you...09341894- SKU:
- 09341894
- Availability:
- Ships Same Business Day
- Weight:
- 0.29 LBS
- PRODUCT NAME:
- GASKET
- UNITS:
- KIT
- TYPE:
- ENGINE
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
$172.14 -
MOOSE RACING Motor Gasket Kit with Seal - KX450F 811482
MOOSE RACING
$196.71A complete engine and transmission rebuild demands precision-fit gaskets and seals—any compromise on fitment risks oil leaks, compression loss, and catastrophic failure. This Moose Racing kit eliminates the guesswork by providing OEM-equivalent seals and...09341895- SKU:
- 09341895
- Availability:
- Ships Same Business Day
- Weight:
- 0.46 LBS
- PRODUCT NAME:
- GASKET
- TYPE:
- COMPLETE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- ENGINE
$196.71 -
MOOSE RACING Top End Gasket Kit - RMZ 450 810595
MOOSE RACING
$91.75A top-end rebuild demands precision—and OEM gasket sets come with OEM pricing. The MOOSE RACING Top End Gasket Kit delivers complete engine sealing at a fraction of the cost, with high-tech materials and genuine OEM oil seals engineered for durability...09341896- SKU:
- 09341896
- Availability:
- Ships Same Business Day
- Weight:
- 0.17 LBS
- PRODUCT NAME:
- GASKET
- TYPE:
- TOP END
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$91.75 -
MOOSE RACING Piston Ring - For 39.47 mm Piston MSE53010003950
MOOSE RACING
$20.95A worn or damaged piston ring compromises compression, increases blowby, and tanks your engine's efficiency and power output. MOOSE Racing's precision-engineered replacement ring restores proper sealing between piston and cylinder wall, bringing your...09120394- SKU:
- 09120394
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- RIDING STYLE:
- OFF-ROAD
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON RING
- UNITS:
- EACH
$20.95 -
MOOSE RACING Piston Ring - For 44.45 mm Piston MSE53010004450
MOOSE RACING
$23.95A worn or damaged piston ring compromises compression, increases blow-by, and tanks engine efficiency—costing you power and reliability on the track or street. MOOSE RACING's precision-engineered replacement rings restore optimal sealing and combustion...09120395- SKU:
- 09120395
- Availability:
- Ships Same Business Day
- Weight:
- 0.01 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- PRODUCT NAME:
- PISTON RING
- PISTON SIZE METRIC:
- STANDARD
$23.95 -
MOOSE RACING Piston Ring - For 44.97 mm Piston MSE53010004500
MOOSE RACING
$24.95A worn or damaged piston ring compromises combustion chamber seal, resulting in lost compression, increased blowby, and reduced power output. The MOOSE RACING Piston Ring MSE53010004500 restores proper ring sealing on your 44.97 mm piston, ensuring...09120396- SKU:
- 09120396
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- PISTON RING
- PISTON SIZE METRIC:
- STANDARD
$24.95 -
MOOSE RACING Piston Ring - For 47.45 mm Piston MSE53010004750
MOOSE RACING
$24.10A worn or damaged piston ring compromises compression, increases blow-by, and tanks your engine's efficiency and power output. The MOOSE RACING Piston Ring delivers OEM-quality performance to restore proper ring seal, reduce oil consumption, and maintain...09120397- SKU:
- 09120397
- Availability:
- Ships Same Business Day
- Weight:
- 0.01 LBS
- PRODUCT NAME:
- PISTON RING
- RIDING STYLE:
- OFF-ROAD
- PISTON SIZE METRIC:
- STANDARD
- UNITS:
- EACH
$24.10 -
MOOSE RACING Valve Shim - 9.48 x 1.45 - 5 pack MSE5PK948145
MOOSE RACING
$9.95Proper valve shim sizing is critical to maintaining correct valve clearance and preventing costly engine damage—and having a complete range on hand eliminates guesswork during valve train adjustments. MOOSE Racing shims are forged from 4140 cold-rolled...09261933- SKU:
- 09261933
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- VALVE SHIM THICKNESS METRIC:
- 1.45 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
MOOSE RACING Valve Shim - 9.48 x 1.50 - 5 pack MSE5PK948150
MOOSE RACING
$9.95Maintaining precise valve clearances is critical to engine performance, reliability, and longevity. MOOSE Racing valve shims give you the exact sizing and durability needed to dial in your valve train without guesswork or premature wear. This 5-pack...09261934- SKU:
- 09261934
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- ATV
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 1.50 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- VALVE
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
MOOSE RACING Valve Shim - 9.48 x 1.55 - 5 pack MSE5PK948155
MOOSE RACING
$9.95Valve shim maintenance is critical to keeping your engine's valve train operating at peak precision, and having the right sizes on hand eliminates guesswork during adjustment. These MOOSE RACING shims are forged from 4140 cold rolled steel—not...09261935- SKU:
- 09261935
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- VALVE SHIM THICKNESS METRIC:
- 1.55 MM
- RIDING STYLE:
- SNOW
- UNITS:
- 5 PACK
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
$9.95 -
MOOSE RACING Valve Shim - 9.48 x 1.70 - 5 pack MSE5PK948170
MOOSE RACING
$9.95Proper valve shim selection is critical for maintaining precise valve clearances and preventing costly engine damage. These MOOSE RACING shims eliminate guesswork during valve train maintenance, allowing you to dial in exact specifications with...09261938- SKU:
- 09261938
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 1.70 MM
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- SNOW
- UNITS:
- 5 PACK
$9.95 -
MOOSE RACING Valve Shim - 9.48 x 1.75 - 5 pack MSE5PK948175
MOOSE RACING
$9.95Precision valve shim work demands accuracy and reliability—this 5-pack ensures you have quality refills on hand when you need them. Forged from 4140 cold-rolled steel rather than sintered material, these shims deliver the durability required for proper...09261939- SKU:
- 09261939
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- VALVE SHIM THICKNESS METRIC:
- 1.75 MM
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- VALVE
$9.95 -
MOOSE RACING Valve Shim - 9.48 x 1.80 - 5 pack MSE5PK948180
MOOSE RACING
$9.95Precision valve train maintenance demands reliable, durable shims that won't compromise your engine's performance. MOOSE RACING valve shims eliminate guesswork during valve lash adjustments—each shim is laser-etched for instant identification, so you...09261940- SKU:
- 09261940
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- SNOW
- UNITS:
- 5 PACK
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 1.80 MM
$9.95 -
MOOSE RACING Valve Shim - 9.48 x 1.90 - 5 pack MSE5PK948190
MOOSE RACING
$9.95Valve shim replacement is an essential maintenance task that directly impacts engine performance, valve clearance, and longevity of your valve train. This 5-pack from MOOSE Racing gives you the precise shims you need to dial in correct valve lash without...09261942- SKU:
- 09261942
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- STREET
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- OFF-ROAD
- VALVE SHIM THICKNESS METRIC:
- 1.90 MM
$9.95 -
MOOSE RACING Crank Bearing - Husqvarna 24-1107
MOOSE RACING
$74.95A worn or damaged crankshaft bearing directly impacts engine reliability and power delivery on your 2-stroke. This MOOSE RACING kit restores proper crankshaft support and reduces parasitic friction from day one, giving you the dependable performance...09240228- SKU:
- 09240228
- Availability:
- Ships Same Business Day
- Weight:
- 1.12 LBS
- RIDING STYLE:
- STREET
- UNITS:
- KIT
- APPLICATION:
- CRANKSHAFT
- PRODUCT NAME:
- BEARING
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- BALL
$74.95
