Dirt Bike Piston and Ring Kits
Dirt Bike Piston & Ring Kits for Yamaha YZ85, WR250 & YZ250 at JJ Motorsports
Rebuild your dirt bike's top end for maximum power and reliability with premium piston and ring kits from JJ Motorsports, forged from high-strength aluminum for superior heat resistance, lightweight performance, and precise fit in motocross, enduro, and trail riding. Our selection includes complete kits with pistons, high-performance rings, wrist pins, circlips, top-end bearings, and gaskets designed for enhanced combustion efficiency, reduced blow-by, and longer engine life under high-RPM abuse. Compatible with popular models like Yamaha YZ85 (2002-2018), WR250, and YZ250, these Wiseco-engineered components feature CNC-machined crowns for optimal cam shape, ArmorGlide skirt coatings for low friction, and 4032 alloy construction for durability in dusty, aggressive conditions. Whether you're refreshing a youth 85cc 2-stroke or upgrading a 250cc big bore, these kits ensure crisp throttle response, better sealing, and race-ready power without the need for custom boring—perfect for DIY rebuilds or pro-level maintenance.
Shop trusted brands like Wiseco for race-proven quality. Explore related categories such as dirt bike engine for cylinders and valves or dirt bike air and fuel for carburetors and jets.
Top Dirt Bike Piston & Ring Kits
- Wiseco YZ85 2002-2018 Piston Kit with Gaskets PK1202 – 47.50mm forged aluminum piston kit for Yamaha YZ85 2-stroke; includes rings, wrist pin, circlips, bearing, and gaskets for enhanced combustion and throttle response.
- Wiseco 68.00mm Piston Kit with Gaskets Yamaha WR/YZ 250 PK1563 – Complete big bore kit for Yamaha WR250/YZ250; features forged piston, rings, wrist pin, circlips, and top-end gaskets for superior power and sealing.
Browse our in-stock inventory below with same-day shipping and expert support. Free shipping on orders over $99! Questions? Contact us for fitment advice!
- Product
- Qty in Cart
- Quantity
- Price
- Subtotal
-
PROX Piston Kit 01.3220.A
PROX
$121.95Your engine's pistons are the hardworking heart of combustion—and when they wear, performance suffers. The PROX Piston Kit 01.3220.A restores your engine to OEM specifications with...PX5060A- SKU:
- PX5060A
- Availability:
- Ships Same Business Day
- Weight:
- 0.42 LBS
- PISTON DIAMETER METRIC:
- 53.94 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- BORE SIZE METRIC:
- 53.94 MM
- PISTON SIZE METRIC:
- STANDARD SIZE A
- RIDING STYLE:
- OFF-ROAD
$121.95 -
PROX Piston Kit 01.3220.B
PROX
$101.95A worn or damaged piston directly compromises engine compression, power output, and fuel efficiency—making a quality replacement essential for reliable performance. The PROX Piston Kit 01.3220.B...PX5060B- SKU:
- PX5060B
- Availability:
- Ships Same Business Day
- Weight:
- 0.42 LBS
- BORE SIZE METRIC:
- 53.95 MM
- PISTON SIZE METRIC:
- STANDARD SIZE B
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 53.95 MM
- PRODUCT NAME:
- PISTON KIT
$101.95Qty in Cart: 0Quantity:Price:$101.95Subtotal: -
PROX Piston Kit 01.3220.C
PROX
$105.95Your engine's ability to handle sustained RPMs and maintain combustion efficiency depends entirely on piston quality—worn or substandard pistons lead to blow-by, compression loss, and catastrophic...PX5060C- SKU:
- PX5060C
- Availability:
- Ships Same Business Day
- Weight:
- 0.42 LBS
- PISTON DIAMETER METRIC:
- 53.96 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE C
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- BORE SIZE METRIC:
- 53.96 MM
- PRODUCT NAME:
- PISTON KIT
$105.95Qty in Cart: 0Quantity:Price:$105.95Subtotal: -
PROX Piston Kit 01.3220.D
PROX
$105.95Worn or damaged pistons compromise combustion efficiency, reduce power output, and risk catastrophic engine failure. The PROX Piston Kit 01.3220.D delivers OEM-equivalent performance with precision...PX5060D- SKU:
- PX5060D
- Availability:
- Ships Same Business Day
- Weight:
- 0.72 LBS
- PRODUCT NAME:
- PISTON KIT
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 53.97 MM
- PISTON DIAMETER METRIC:
- 53.97 MM
- PISTON SIZE METRIC:
- STANDARD SIZE D
- RIDING STYLE:
- OFF-ROAD
$105.95Qty in Cart: 0Quantity:Price:$105.95Subtotal: -
PROX Piston Kit 01.3310.B
PROX
$129.95Worn or damaged pistons compromise engine efficiency, power delivery, and longevity. The PROX Piston Kit 01.3310.B restores your engine to OEM performance specifications with precision-manufactured...PX5070B- SKU:
- PX5070B
- Availability:
- Ships Same Business Day
- Weight:
- 0.63 LBS
- PISTON SIZE METRIC:
- STANDARD SIZE B
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 66.94 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 66.94 MM
- PRODUCT NAME:
- PISTON KIT
$129.95Qty in Cart: 0Quantity:Price:$129.95Subtotal: -
PROX Piston Kit 01.3310.C
PROX
$129.95A worn or damaged piston directly compromises engine efficiency, reliability, and power output. The PROX Piston Kit 01.3310.C delivers OEM-equivalent performance with precision engineering, ensuring...PX5070C- SKU:
- PX5070C
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE C
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 66.95 MM
- BORE SIZE METRIC:
- 66.95 MM
- PRODUCT NAME:
- PISTON KIT
$129.95Qty in Cart: 0Quantity:Price:$129.95Subtotal: -
PROX Piston Kit 01.3320.A
PROX
$143.95When your engine's original pistons show signs of wear—whether it's blowby, loss of compression, or declining performance—a quality replacement kit restores cylinder sealing and combustion efficiency...PX5200A- SKU:
- PX5200A
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- BORE SIZE METRIC:
- 66.34 MM
- PISTON SIZE METRIC:
- STANDARD SIZE A
- PISTON DIAMETER METRIC:
- 66.34 MM
- PRODUCT NAME:
- PISTON KIT
$143.95 -
PROX Piston Kit 01.3320.B
PROX
$143.95A piston kit is the heart of your engine's combustion cycle, and worn or damaged pistons rob you of compression, power, and reliability. The PROX Piston Kit 01.3320.B delivers OEM-equivalent...PX5200B- SKU:
- PX5200B
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- PISTON SIZE METRIC:
- STANDARD SIZE B
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 66.35 MM
- BORE SIZE METRIC:
- 66.35 MM
- PRODUCT NAME:
- PISTON KIT
$143.95 -
PROX Piston Kit 01.3320.C
PROX
$129.95When engine wear compromises compression and power delivery, a quality piston kit is the foundation of a proper rebuild. The PROX Piston Kit 01.3320.C delivers OEM-equivalent performance with...PX5200C- SKU:
- PX5200C
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- PISTON DIAMETER METRIC:
- 66.36 MM
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 66.36 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE C
- UNITS:
- EACH
- PRODUCT NAME:
- PISTON KIT
$129.95Qty in Cart: 0Quantity:Price:$129.95Subtotal: -
PROX Piston Kit 01.2314.B
PROX
$132.95A piston failure means catastrophic engine damage—and the PROX Piston Kit 01.2314.B is engineered to prevent exactly that. Built to OEM specifications using high-silicon aluminum and precision CNC...PX7080B- SKU:
- PX7080B
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- ENGINE TYPE:
- 2-STROKE
- PISTON DIAMETER METRIC:
- 67.95 MM
- PISTON SIZE METRIC:
- +0.01 MM
- PRODUCT NAME:
- PISTON KIT
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 67.95 MM
- RIDING STYLE:
- OFF-ROAD
$132.95 -
PROX Piston Kit 01.2314.C
PROX
$129.95A worn or damaged piston is a silent killer of engine performance—it compromises compression, increases blow-by, and can lead to catastrophic failure if left unchecked. The PROX Piston Kit 01.2314.C...PX7080C- SKU:
- PX7080C
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
- PISTON DIAMETER METRIC:
- 67.96 MM
- PISTON SIZE METRIC:
- STANDARD SIZE C
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 67.96 MM
- PRODUCT NAME:
- PISTON KIT
$129.95Qty in Cart: 0Quantity:Price:$129.95Subtotal: -
PROX Piston Kit 01.2314.D
PROX
$132.95Your engine's power delivery and efficiency depend entirely on piston quality, and worn or damaged pistons directly compromise compression, fuel economy, and reliability. The PROX Piston Kit 01.2314...PX7080D- SKU:
- PX7080D
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- PISTON KIT
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE D
- UNITS:
- EACH
- BORE SIZE METRIC:
- 67.97 MM
- PISTON DIAMETER METRIC:
- 67.97 MM
- RIDING STYLE:
- OFF-ROAD
$132.95 -
PROX Piston Kit 01.2321.A
PROX
$132.95Factory piston performance demands precision engineering and material integrity—two hallmarks of the PROX Piston Kit 01.2321.A. Whether you're rebuilding after high-mileage wear or seeking the...PX7130A- SKU:
- PX7130A
- Availability:
- Ships Same Business Day
- Weight:
- 0.69 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON DIAMETER METRIC:
- 66.35 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- PISTON SIZE METRIC:
- STANDARD SIZE A
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 66.35 MM
$132.95 -
PROX Piston Kit 01.2321.B
PROX
$132.95Worn or damaged pistons compromise engine efficiency, power delivery, and reliability—especially under high-load conditions. The PROX Piston Kit 01.2321.B restores your engine to OEM performance...PX7130B- SKU:
- PX7130B
- Availability:
- Ships Same Business Day
- Weight:
- 0.69 LBS
- BORE SIZE METRIC:
- 66.36 MM
- PISTON SIZE METRIC:
- STANDARD SIZE B
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 66.36 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
$132.95 -
PROX Piston Kit 01.2321.C
PROX
$132.95Worn or damaged pistons compromise compression, fuel efficiency, and engine reliability—often requiring a complete teardown to address. The PROX Piston Kit 01.2321.C delivers OEM-equivalent...PX7130C- SKU:
- PX7130C
- Availability:
- Ships Same Business Day
- Weight:
- 0.65 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE C
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 66.37 MM
- BORE SIZE METRIC:
- 66.37 MM
- PRODUCT NAME:
- PISTON KIT
$132.95 -
PROX Piston Kit 01.2321.D
PROX
$132.95A worn or damaged piston compromises combustion efficiency, reduces power output, and accelerates engine wear. The PROX Piston Kit 01.2321.D restores OEM performance specifications with...PX7130D- SKU:
- PX7130D
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- BORE SIZE METRIC:
- 66.38 MM
- PISTON DIAMETER METRIC:
- 66.38 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE D
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- PRODUCT NAME:
- PISTON KIT
$132.95 -
PROX Piston Kit 01.2215.C
PROX
$121.95A piston kit is the foundation of reliable engine performance—worn or damaged pistons compromise compression, power delivery, and longevity. The PROX Piston Kit 01.2215.C delivers OEM-equivalent...PX7214C- SKU:
- PX7214C
- Availability:
- Ships Same Business Day
- Weight:
- 0.44 LBS
- BORE SIZE METRIC:
- 53.96 MM
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- PISTON KIT
- PISTON SIZE METRIC:
- +0.02 MM
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 53.96 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
$121.95 -
PROX Piston Kit 01.2217.A
PROX
$121.95Worn or damaged pistons compromise engine compression, throttle response, and fuel efficiency—leaving you stranded or forced into costly rebuilds. The PROX Piston Kit 01.2217.A restores your engine...PX7215A- SKU:
- PX7215A
- Availability:
- Ships Same Business Day
- Weight:
- 0.44 LBS
- ENGINE TYPE:
- 2-STROKE
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 53.95 MM
- PISTON DIAMETER METRIC:
- 53.95 MM
- RIDING STYLE:
- OFF-ROAD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
$121.95 -
PROX Piston Kit 01.2217.B
PROX
$121.95If you're rebuilding an engine or restoring performance after high-mileage wear, piston quality directly impacts reliability, compression consistency, and longevity under load. The PROX Piston Kit 01...PX7215B- SKU:
- PX7215B
- Availability:
- Ships Same Business Day
- Weight:
- 0.44 LBS
- PISTON DIAMETER METRIC:
- 53.96 MM
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 53.96 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON SIZE METRIC:
- +0.01 MM
- PRODUCT NAME:
- PISTON KIT
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
$121.95Qty in Cart: 0Quantity:Price:$121.95Subtotal: -
PROX Piston Kit 01.2217.C
PROX
$105.95When your engine demands precision engineering and proven reliability, OEM-equivalent performance becomes non-negotiable. The PROX Piston Kit 01.2217.C delivers the exact specifications your engine...PX7215C- SKU:
- PX7215C
- Availability:
- Ships Same Business Day
- Weight:
- 0.44 LBS
- ENGINE TYPE:
- 2-STROKE
- PISTON SIZE METRIC:
- +0.02 MM
- PRODUCT NAME:
- PISTON KIT
- PISTON DIAMETER METRIC:
- 53.97 MM
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 53.97 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
$105.95Qty in Cart: 0Quantity:Price:$105.95Subtotal:
