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 Shims - 5 pack 29.748310
PROX
$9.95Valve shim wear directly impacts engine performance and reliability—precision valve timing depends on exact shim clearances, and worn units compromise both. PROX Valve Shims deliver OEM-quality...09260908- SKU:
- 09260908
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- OUTSIDE DIAMETER METRIC:
- 7.48 MM
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 3.10 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 Shims - 5 pack 29.748320
PROX
$9.95Valve shim wear is one of the most common causes of valve train noise and performance loss in high-revving engines. These PROX shims deliver precision fitment and heat-treated durability at a...09260910- SKU:
- 09260910
- Availability:
- Ships Same Business Day
- Weight:
- 0.01 LBS
- VALVE SHIM THICKNESS METRIC:
- 3.20 MM
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE
- OUTSIDE DIAMETER METRIC:
- 7.48 MM
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
$9.95 -
PROX Valve Shim Kit 29.VSA890
PROX
$77.95Valve shim wear is one of the most common causes of performance loss and engine noise in high-revving applications. The PROX Valve Shim Kit 29.VSA890 delivers precision-engineered replacements that...09260917- SKU:
- 09260917
- Availability:
- Ships Same Business Day
- Weight:
- 0.54 LBS
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- KIT
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- VALVE SHIM THICKNESS METRIC:
- 1.72 MM - 2.60 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
$77.95 -
PROX Valveshim - 5 pack 29.890172
PROX
$9.95Valve shims are critical wear items that directly affect valve clearance and engine timing precision—neglect them and you risk catastrophic valvetrain failure. PROX Valveshims deliver OEM-equivalent...09260918- SKU:
- 09260918
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- WATERCRAFT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 1.72 MM
- RIDING STYLE:
- STREET
$9.95 -
PROX Valveshim - 5 pack 29.890188
PROX
$9.95Valve shims wear down over time, throwing off your engine's valve clearances and compromising performance and reliability. PROX Valveshims give you a cost-effective replacement option without the...09260922- SKU:
- 09260922
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 1.88 MM
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valveshim - 5 pack 29.890192
PROX
$9.95Valve shims are wear components that demand precision and durability—especially under high RPM conditions where tolerance stack-up can quickly degrade performance. The PROX Valveshim 5-pack delivers...09260923- SKU:
- 09260923
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- RIDING STYLE:
- STREET
- RIDING STYLE:
- UTV
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE
- VALVE SHIM THICKNESS METRIC:
- 1.92 MM
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valveshim - 5 pack 29.890196
PROX
$9.95Valve shims are critical wear components that directly impact valve clearance, timing accuracy, and engine longevity. PROX Valveshims deliver OEM-equivalent precision at a fraction of the cost,...09260924- SKU:
- 09260924
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- VALVE SHIM THICKNESS METRIC:
- 1.96 MM
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- STREET
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valveshim - 5 pack 29.890200
PROX
$9.95Valve shims are critical to maintaining proper valve clearance and preventing costly engine damage from over-tightening or excessive wear. The PROX Valveshim 5-pack offers precision-machined...09260925- SKU:
- 09260925
- 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
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- OFF-ROAD
- VALVE SHIM THICKNESS METRIC:
- 2.00 MM
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valveshim - 5 pack 29.890204
PROX
$10.95Valve shim wear directly impacts valve clearance, which affects combustion efficiency, valve timing, and engine longevity. The PROX Valveshim 5-pack (29.890204) delivers precision-machined...09260926- SKU:
- 09260926
- 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:
- 8.90 MM
- RIDING STYLE:
- OFF-ROAD
- VALVE SHIM THICKNESS METRIC:
- 2.04 MM
- RIDING STYLE:
- STREET
- RIDING STYLE:
- WATERCRAFT
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
$10.95 -
PROX Valveshim - 5 pack 29.890208
PROX
$10.95Valve shims are critical to maintaining proper valve clearance and preventing catastrophic engine damage from improper valvetrain geometry. These PROX shims deliver precision-machined consistency and...09260927- SKU:
- 09260927
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- VALVE SHIM THICKNESS METRIC:
- 2.08 MM
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
$10.95Qty in Cart: 0Quantity:Price:$10.95Subtotal: -
PROX Valveshim - 5 pack 29.890212
PROX
$10.95Valve shims are critical wear items that directly impact valve clearance, engine timing, and overall performance—neglecting them leads to improper valve operation and potential damage. PROX...09260928- SKU:
- 09260928
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- STREET
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- VALVE SHIM THICKNESS METRIC:
- 2.12 MM
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- WATERCRAFT
$10.95Qty in Cart: 0Quantity:Price:$10.95Subtotal: -
PROX Valveshim - 5 pack 29.890216
PROX
$10.95Valve shim wear directly impacts your engine's valve clearance, compression, and overall performance—left unchecked, it leads to costly damage and downtime. PROX Valveshims deliver...09260929- SKU:
- 09260929
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.16 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- ATV
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- WATERCRAFT
$10.95 -
PROX Valveshim - 5 pack 29.890220
PROX
$10.95Valve shim wear is inevitable in high-performance engines, but replacing them doesn't require the expense and downtime of OEM components. The PROX Valveshim 5-pack delivers precision-engineered...09260930- SKU:
- 09260930
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- UTV
- TYPE:
- VALVE
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- VALVE SHIM THICKNESS METRIC:
- 2.20 MM
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
$10.95 -
PROX Valveshim - 5 pack 29.890224
PROX
$10.95Valve shims wear down with every engine cycle, and worn shims throw off valve clearance—leading to reduced power, increased noise, and potential valve damage. The PROX Valveshim 5-pack gives you...09260931- SKU:
- 09260931
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- RIDING STYLE:
- STREET
- RIDING STYLE:
- WATERCRAFT
- VALVE SHIM THICKNESS METRIC:
- 2.24 MM
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- UNITS:
- 5 PACK
$10.95 -
PROX Valveshim - 5 pack 29.890228
PROX
$10.95Valve shims are critical to maintaining proper valve clearance and ensuring consistent engine performance across heat cycles. The PROX 5-pack gives you multiple precision replacements on hand,...09260932- SKU:
- 09260932
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- STREET
- RIDING STYLE:
- WATERCRAFT
- VALVE SHIM THICKNESS METRIC:
- 2.28 MM
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- UNITS:
- 5 PACK
$10.95 -
PROX Valveshim - 5 pack 29.890232
PROX
$9.95Valve shims are critical wear components that demand precision and durability—especially in high-RPM applications where tolerance stack-up directly impacts engine performance and reliability. The...09260933- SKU:
- 09260933
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- TYPE:
- VALVE
- VALVE SHIM THICKNESS METRIC:
- 2.32 MM
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- RIDING STYLE:
- WATERCRAFT
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- UNITS:
- 5 PACK
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valveshim - 5 pack 29.890236
PROX
$9.95Valve shim wear is one of the most common maintenance issues in high-performance engines, directly affecting valve clearance and engine efficiency. The PROX Valveshim 5-pack offers a cost-effective...09260934- SKU:
- 09260934
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- RIDING STYLE:
- ATV
- TYPE:
- VALVE
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- OFF-ROAD
- VALVE SHIM THICKNESS METRIC:
- 2.36 MM
- RIDING STYLE:
- STREET
- RIDING STYLE:
- WATERCRAFT
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- UNITS:
- 5 PACK
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valveshim - 5 pack 29.890240
PROX
$9.95Valve shims are critical wear items that directly impact your engine's valve clearance and overall performance. When OEM shims wear or require replacement, PROX delivers precision-machined...09260935- SKU:
- 09260935
- Availability:
- Ships Same Business Day
- Weight:
- 0.01 LBS
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE
- RIDING STYLE:
- STREET
- RIDING STYLE:
- WATERCRAFT
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- VALVE SHIM THICKNESS METRIC:
- 2.40 MM
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- UTV
- UNITS:
- 5 PACK
$9.95Qty in Cart: 0Quantity:Price:$9.95Subtotal: -
PROX Valveshim - 5 pack 29.890244
PROX
$9.95Valve shims are critical wear items in high-revving engines, and OEM replacements can drain your budget fast. The PROX Valveshim 5-pack delivers precision-machined replacements at a fraction of OEM...09260936- SKU:
- 09260936
- Availability:
- Ships Same Business Day
- Weight:
- 0.01 LBS
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- ATV
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- PRODUCT NAME:
- SHIM KIT
- RIDING STYLE:
- SNOW
- RIDING STYLE:
- WATERCRAFT
- UNITS:
- 5 PACK
- VALVE SHIM THICKNESS METRIC:
- 2.44 MM
- RIDING STYLE:
- STREET
- RIDING STYLE:
- UTV
$9.95 -
PROX Valveshim - 5 pack 29.890256
PROX
$9.95Valve shim wear directly impacts valve clearance, which affects combustion timing, power delivery, and engine longevity. PROX Valveshims give you precision replacements without the OEM price tag,...09260939- SKU:
- 09260939
- Availability:
- Ships Same Business Day
- Weight:
- 0.02 LBS
- OUTSIDE DIAMETER METRIC:
- 8.90 MM
- RIDING STYLE:
- WATERCRAFT
- 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
- VALVE SHIM THICKNESS METRIC:
- 2.56 MM
- RIDING STYLE:
- STREET
$9.95
