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 Valve Shim - 8.90 x 1.84 - 5 pack MSE5PK890184
MOOSE RACING
$10.95Proper valve clearance is critical to engine performance and longevity—even a few thousandths of an inch off can hurt compression, increase valve train noise, and accelerate wear. The MOOSE RACING 8...09261908- SKU:
- 09261908
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 1.84 MM
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- SNOW
- UNITS:
- 5 PACK
$10.95 -
MOOSE RACING Valve Shim - 9.48 x 2.10 - 5 pack MSE5PK948210
MOOSE RACING
$9.95Valve train maintenance demands precision, and these MOOSE RACING shims deliver exactly that. When you're dialing in your valve clearances, having a complete set of accurately-sized...09261946- SKU:
- 09261946
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- SNOW
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.10 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- VALVE
- UNITS:
- 5 PACK
$9.95 -
MOOSE RACING Valve Shim - 9.48 x 2.15 - 5 pack MSE5PK948215
MOOSE RACING
$9.95Valve shim maintenance is critical to keeping your engine running at peak performance, and having quality shims on hand eliminates downtime during valve train adjustments. MOOSE Racing shims are...09261947- SKU:
- 09261947
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- MATERIAL:
- ROLLED
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.15 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
$9.95 -
MOOSE RACING Valve Shim - 9.48 x 2.25 - 5 pack MSE5PK948225
MOOSE RACING
$9.95Valve shim maintenance is critical for precise valve train geometry and consistent engine performance. These MOOSE RACING shims eliminate guesswork during valve adjustments by offering accurate,...09261949- SKU:
- 09261949
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- VALVE SHIM THICKNESS METRIC:
- 2.25 MM
- 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
$9.95 -
MOOSE RACING Valve Shim - 9.48 x 2.30 - 5 pack MSE5PK948230
MOOSE RACING
$9.95Proper valve shim selection is critical for maintaining correct valve clearances and engine performance—neglecting this during maintenance can lead to loss of power, increased noise, and premature...09261950- SKU:
- 09261950
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- STREET
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- VALVE SHIM THICKNESS METRIC:
- 2.30 MM
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
$9.95 -
MOOSE RACING Valve Shim - 9.48 x 2.35 - 5 pack MSE5PK948235
MOOSE RACING
$9.95Valve shim maintenance is critical for maintaining proper valve clearances and extending your engine's service life. MOOSE RACING's forged 4140 cold-rolled steel shims eliminate guesswork with...09261951- SKU:
- 09261951
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- STREET
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.35 MM
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- SNOW
$9.95 -
MOOSE RACING Valve Shim - 9.48 x 2.40 - 5 pack MSE5PK948240
MOOSE RACING
$9.95Proper valve shim selection is critical for maintaining correct valve clearances and preventing costly engine damage or performance loss. These MOOSE RACING shims eliminate guesswork during valve...09261952- SKU:
- 09261952
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- VALVE SHIM THICKNESS METRIC:
- 2.40 MM
- 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
$9.95 -
MOOSE RACING Valve Shim - 9.48 x 2.45 - 5 pack MSE5PK948245
MOOSE RACING
$9.95Valve train maintenance demands precision, and guesswork has no place in your engine bay. These MOOSE RACING valve shims eliminate uncertainty with laser-etched sizing and forged 4140 steel...09261953- SKU:
- 09261953
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- SNOW
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.45 MM
$9.95 -
MOOSE RACING Valve Shim - 9.48 x 2.55 - 5 pack MSE5PK948255
MOOSE RACING
$9.95Maintaining precise valve clearances is critical to engine performance, longevity, and reliability—and having a complete shim kit on hand eliminates guesswork during valve train service. MOOSE RACING...09261955- SKU:
- 09261955
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.55 MM
$9.95 -
MOOSE RACING Valve Shim - 9.48 x 2.60 - 5 pack MSE5PK948260
MOOSE RACING
$9.95Precision valve train maintenance demands reliable, accurate shims that won't let you down mid-rebuild. These MOOSE RACING valve shims are forged from 4140 cold rolled steel—not sintered—delivering...09261956- SKU:
- 09261956
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- MATERIAL:
- ROLLED
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.60 MM
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- VALVE
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
$9.95 -
MOOSE RACING Valve Shim - 9.48 x 2.65 - 5 pack MSE5PK948265
MOOSE RACING
$9.95Maintaining proper valve clearance is critical to engine performance and longevity—and having precision shims on hand ensures you're never caught without the right size during a rebuild or adjustment...09261957- SKU:
- 09261957
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- MATERIAL:
- ROLLED
- RIDING STYLE:
- ATV
- PRODUCT NAME:
- SHIM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.65 MM
- MATERIAL:
- STEEL
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- VALVE
$9.95 -
MOOSE RACING Clutch Cylinder Guard - 125/200 13-090
MOOSE RACING
$32.95Your hydraulic clutch cylinder is vulnerable to chain contact and impact damage—especially in high-stress racing environments. The MOOSE RACING Clutch Cylinder Guard delivers direct protection with...09500148- SKU:
- 09500148
- Availability:
- Ships Same Business Day
- Weight:
- 0.38 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- COLOR/FINISH:
- BLACK
- MATERIAL:
- ALUMINUM
- PRODUCT NAME:
- CASE SAVER
- RIDING STYLE:
- STREET
- TYPE:
- SLAVE CYLINDER
- COLOR/FINISH:
- ANODIZED
$32.95Qty in Cart: 0Quantity:Price:$32.95Subtotal: -
MOOSE RACING Clutch Cylinder Guard - 250/300 13-091
MOOSE RACING
$32.95Hydraulic clutch cylinders are vulnerable to chain strikes and debris during aggressive riding—a single impact can compromise your clutch engagement and sideline your bike. The MOOSE RACING Clutch...09500149- SKU:
- 09500149
- Availability:
- Ships Same Business Day
- Weight:
- 0.37 LBS
- TYPE:
- SLAVE CYLINDER
- COLOR/FINISH:
- BLACK
- MATERIAL:
- ALUMINUM
- PRODUCT NAME:
- CASE SAVER
- RIDING STYLE:
- STREET
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- COLOR/FINISH:
- ANODIZED
$32.95 -
MOOSE RACING Piston Kit - 53.94 mm MSE22189B
MOOSE RACING
$146.95If you're rebuilding an engine or recovering from ring blow-by, a quality piston kit is non-negotiable. MOOSE Racing's gravity-cast design with 18% silicon content resists wear and thermal...09102669- SKU:
- 09102669
- Availability:
- Ships Same Business Day
- Weight:
- 0.37 LBS
- ENGINE TYPE:
- 2-STROKE
- STYLE:
- CAST REPLICA
- COMPRESSION RATIO IMPERIAL:
- STOCK
- PISTON DIAMETER METRIC:
- 53.94 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- UNITS:
- KIT
- DISPLACEMENT:
- 125 CC
- CYLINDER DIAMETER METRIC:
- 54.00 MM
- PRODUCT NAME:
- PISTON KIT
$146.95 -
MOOSE RACING Piston Kit - 53.94 mm MSE22685C
MOOSE RACING
$99.95A piston kit is one of the most critical internal upgrades for extending engine life and maintaining peak performance under high-load conditions. The MOOSE Racing MSE22685C combines gravity-cast...09102689- SKU:
- 09102689
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- PISTON DIAMETER METRIC:
- 53.94 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- PISTON KIT
- PISTON MATERIAL:
- ALUMINUM ALLOY
$99.95Qty in Cart: 0Quantity:Price:$99.95Subtotal: -
MOOSE RACING Piston Kit - 44.45 mm MSE22860B
MOOSE RACING
$113.35A piston kit is fundamental to engine longevity and reliability—especially under high-load conditions. The MOOSE RACING MSE22860B combines precision gravity-cast construction with wear-resistant...09102697- SKU:
- 09102697
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON DIAMETER METRIC:
- 44.45 MM
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$113.35 -
MOOSE RACING Cylinder - Standard - FC250 MSE50006
MOOSE RACING
$498.95A worn or damaged cylinder directly compromises engine performance, throttle response, and overall reliability. The MOOSE RACING Cylinder restores your FC250 to OEM specifications with...09310879- SKU:
- 09310879
- Availability:
- Ships Same Business Day
- Weight:
- 2.55 LBS
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- PRODUCT NAME:
- CYLINDER
- MATERIAL:
- ALUMINUM
- MATERIAL:
- CAST
$498.95 -
MOOSE RACING Carb Mid Body Gasket Kit 26-1510
MOOSE RACING
$26.95If your FCR carburetor is leaking fuel or running inconsistently, worn gaskets and O-rings at the mid-body section are likely culprits. This complete gasket kit eliminates the need to source...09351010- SKU:
- 09351010
- Availability:
- Ships Same Business Day
- Weight:
- 0.06 LBS
- PRODUCT NAME:
- GASKET KIT
- APPLICATION:
- CARBURETOR
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$26.95 -
MOOSE RACING Case Saver - YZ125 04-161
MOOSE RACING
$23.95Engine case damage can sideline your YZ125 and drain your wallet fast. The MOOSE RACING Case Saver replaces fragile OEM plastic guards with CNC-machined aluminum that actually protects your engine...09500018- SKU:
- 09500018
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- MATERIAL:
- 6061 ALUMINUM
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- BASE COLOR:
- SILVER
- PRODUCT NAME:
- CASE SAVER
- TYPE:
- ENGINE
- COLOR/FINISH:
- ALUMINUM
$23.95 -
MOOSE RACING Top End Gasket Kit - XR80 810208
MOOSE RACING
$40.11A top-end rebuild demands precision gaskets and seals that won't compromise your engine's integrity or cost you a fortune. The MOOSE RACING Top End Gasket Kit delivers OEM-quality components at a...M810208- SKU:
- M810208
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$40.11Qty in Cart: 0Quantity:Price:$40.11Subtotal:
