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
-
PROX Valve Shim - 5 pack 29.948235
PROX
$10.95Valve shimming is critical to maintaining precise valve clearances and preventing unwanted wear on your cylinder head. These PROX shims are precision-machined to exact tolerances, ensuring consistent...09260965- SKU:
- 09260965
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.35 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
$10.95 -
PROX Valve Shim - 5 pack 29.948240
PROX
$10.95Valve shim clearance is critical to engine performance and longevity—even slight deviations compromise timing and increase wear on critical components. PROX Valve Shims are precision-machined to...09260966- SKU:
- 09260966
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- WATERCRAFT
- VALVE SHIM THICKNESS METRIC:
- 2.40 MM
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- STREET
$10.95 -
PROX Valve Shim - 5 pack 29.948245
PROX
$10.95Valve shimming is critical to maintaining proper valve clearance and preventing catastrophic engine damage from valve float or seat wear. These PROX shims are precision-machined to exact tolerances...09260967- SKU:
- 09260967
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- WATERCRAFT
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.45 MM
$10.95 -
PROX Valve Shim - 5 pack 29.948250
PROX
$10.95Valve shims are critical wear items in high-performance engines, and precision tolerances directly impact valve timing, lift, and overall engine reliability. The PROX Valve Shim 5-pack ensures...09260968- SKU:
- 09260968
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- VALVE SHIM THICKNESS METRIC:
- 2.50 MM
- RIDING STYLE:
- STREET
$10.95 -
PROX Valve Shim - 5 pack 29.948255
PROX
$9.95Valve shim clearance directly impacts your engine's efficiency and longevity—improper spacing leads to valve float, compression loss, and potential catastrophic failure. PROX Valve Shims are...09260969- SKU:
- 09260969
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.55 MM
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- STREET
- RIDING STYLE:
- UTV
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valve Shim - 5 pack 29.948260
PROX
$9.95Valve shim wear directly impacts your engine's compression ratio, valve clearance, and overall performance consistency. These PROX shims maintain precise tolerances through repeated thermal cycles,...09260970- SKU:
- 09260970
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.60 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- WATERCRAFT
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valve Shim - 5 pack 29.948265
PROX
$10.95Valve timing precision directly impacts your engine's power delivery and reliability—even micron-level inconsistencies compound into performance loss and premature wear. PROX valve shims are...09260971- SKU:
- 09260971
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- STREET
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- RIDING STYLE:
- WATERCRAFT
- VALVE SHIM THICKNESS METRIC:
- 2.65 MM
$10.95 -
PROX Valve Shim - 5 pack 29.948270
PROX
$9.95Valve shim clearance directly impacts engine compression, valve timing precision, and overall reliability—especially under high-RPM conditions. PROX Valve Shims are precision-machined to exact...09260972- SKU:
- 09260972
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.70 MM
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valve Shim - 5 pack 29.948275
PROX
$10.95Valve shim clearance is critical to engine reliability and performance—get it wrong, and you're risking bent valves, poor sealing, and costly damage. PROX Valve Shims are precision-machined to exact...09260973- SKU:
- 09260973
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.75 MM
$10.95 -
PROX Valve Shim - 5 pack 29.948285
PROX
$10.95Valve shim selection directly impacts your engine's valve clearance, combustion efficiency, and component longevity. The PROX Valve Shim 5-pack delivers precision-engineered shims with heat-treated...09260975- SKU:
- 09260975
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.85 MM
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
$10.95 -
PROX Valve Shim - 5 pack 29.948290
PROX
$10.95Valve shim clearance directly impacts engine performance, combustion efficiency, and component longevity. PROX Valve Shims are precision-machined to exact tolerances, eliminating guesswork during...09260976- SKU:
- 09260976
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- UNITS:
- 5 PACK
- RIDING STYLE:
- STREET
- RIDING STYLE:
- WATERCRAFT
- RIDING STYLE:
- OFF-ROAD
- VALVE SHIM THICKNESS METRIC:
- 2.90 MM
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
$10.95 -
PROX Valve Shim - 5 pack 29.948320
PROX
$9.95Valve shim clearance directly impacts engine longevity and performance consistency—improper shim specifications lead to valve float, reduced compression, and catastrophic engine damage. PROX Valve...09260982- SKU:
- 09260982
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- UNITS:
- 5 PACK
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- STREET
- RIDING STYLE:
- WATERCRAFT
- VALVE SHIM THICKNESS METRIC:
- 3.20 MM
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valve Shim - 5 pack 29.948350
PROX
$9.95Valve shim selection directly impacts your engine's valve train geometry and performance characteristics. These PROX shims are precision-machined to exacting tolerances, ensuring accurate valve...09260988- SKU:
- 09260988
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- OUTSIDE DIAMETER METRIC:
- 9.48 MM
- RIDING STYLE:
- STREET
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- VALVE SHIM THICKNESS METRIC:
- 3.50 MM
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- WATERCRAFT
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valve Shim Kit 29.VSA1000
PROX
$99.95Valve shims are critical wear items that directly impact valve clearance, combustion efficiency, and engine longevity. OEM replacements come with premium pricing and extended lead times—the PROX...09260989- SKU:
- 09260989
- Availability:
- Ships Same Business Day
- Weight:
- 0.67 LBS
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- VALVE SHIM THICKNESS METRIC:
- 1.85 MM - 3.20 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- KIT
$99.95 -
PROX Valveshim - 10.00 x 2.15 - 5 pack 29.100215
PROX
$9.95Valve shim adjustment is critical to engine performance, and worn or incorrect shims compromise compression, valve timing, and overall reliability. The PROX Valveshim 10.00 x 2.15 delivers...09260996- SKU:
- 09260996
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- TYPE:
- VALVE
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.15 MM
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- UNITS:
- 5 PACK
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valveshim - 10.00 x 2.20 - 5 pack 29.100220
PROX
$9.95Valve shims are critical wear components that directly impact your engine's valvetrain precision and longevity. OEM replacements are expensive and require frequent servicing—PROX valveshims deliver...09260997- SKU:
- 09260997
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.20 MM
- PRODUCT NAME:
- SHIM KIT
- UNITS:
- 5 PACK
$9.95 -
PROX Valveshim - 10.00 x 2.25 - 5 pack 29.100225
PROX
$9.95Valve shimming is critical to maintaining proper valve clearance and engine performance, and worn or incorrect shims lead to costly damage and downtime. PROX Valveshims are precision-engineered...09260998- SKU:
- 09260998
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- RIDING STYLE:
- STREET
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.25 MM
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valveshim - 10.00 x 2.30 - 5 pack 29.100230
PROX
$9.95Valve shim wear directly impacts your engine's valve clearance and overall performance—neglecting worn shims leads to improper valve timing and potential engine damage. PROX Valveshims offer a...09260999- SKU:
- 09260999
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- PRODUCT NAME:
- SHIM KIT
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.30 MM
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- RIDING STYLE:
- STREET
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valveshim - 10.00 x 2.35 - 5 pack 29.100235
PROX
$9.95Valve shim replacement is a critical maintenance task for high-performance engines, and OEM shims come with premium price tags that add up quickly across multiple cylinders. The PROX Valveshim 10.00...09261000- SKU:
- 09261000
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
- RIDING STYLE:
- OFF-ROAD
- VALVE SHIM THICKNESS METRIC:
- 2.35 MM
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- TYPE:
- VALVE
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valveshim - 10.00 x 2.40 - 5 pack 29.100240
PROX
$9.95Valve shims are wear items that demand precision and reliability—improper thickness throws off your valve clearance and compromises engine performance. PROX Valveshims deliver exact OEM dimensions at...09261001- SKU:
- 09261001
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.40 MM
- OUTSIDE DIAMETER METRIC:
- 10.00 MM
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal:
