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
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On Sale
PROX Piston Kit 01.2321.A
PROX
MSRP: $132.95Now: $110.00Was: $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 reliability of OEM-equivalent specifications, this...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
MSRP: $132.95Now: $110.00Was: $132.95 -
On Sale
PROX Piston Kit 01.2321.B
PROX
MSRP: $132.95Now: $110.00Was: $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 specifications with precision-manufactured components...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
MSRP: $132.95Now: $110.00Was: $132.95 -
On Sale
PROX Piston Kit 01.2321.C
PROX
MSRP: $132.95Now: $110.00Was: $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 performance with precision engineering, allowing you to restore...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
MSRP: $132.95Now: $110.00Was: $132.95 -
On Sale
PROX Piston Kit 01.2321.D
PROX
MSRP: $132.95Now: $110.00Was: $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 precision-engineered components manufactured to exacting tolerances...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
MSRP: $132.95Now: $110.00Was: $132.95 -
On Sale
PROX Piston Kit 01.2215.C
PROX
MSRP: $121.95Now: $90.00Was: $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 quality without the OEM price tag, using precision...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
MSRP: $121.95Now: $90.00Was: $121.95Qty in Cart: 0Quantity:Price:MSRP: $121.95Now: $90.00Was: $121.95Subtotal: -
On Sale
PROX Piston Kit 01.2217.A
PROX
MSRP: $121.95Now: $90.00Was: $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 to OEM performance specs with precision-engineered...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
MSRP: $121.95Now: $90.00Was: $121.95 -
On Sale
PROX Piston Kit 01.2217.B
PROX
MSRP: $121.95Now: $90.00Was: $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 01.2217.B delivers OEM-specification performance with...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
MSRP: $121.95Now: $90.00Was: $121.95 -
On Sale
PROX Piston Kit 01.2217.C
PROX
MSRP: $105.95Now: $90.00Was: $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 was designed around, manufactured to exacting tolerances...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
MSRP: $105.95Now: $90.00Was: $105.95 -
On Sale
PROX Piston Kit 01.2215.B
PROX
MSRP: $105.95Now: $90.00Was: $105.95Your engine's pistons are the hardworking heart of combustion—and worn or damaged units directly compromise power output, efficiency, and reliability. The PROX Piston Kit 01.2215.B delivers OEM-equivalent performance with precision engineering you can...PX7214B- SKU:
- PX7214B
- Availability:
- Ships Same Business Day
- Weight:
- 0.44 LBS
- BORE SIZE METRIC:
- 53.95 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON SIZE METRIC:
- +0.01 MM
- PISTON DIAMETER METRIC:
- 53.95 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- PRODUCT NAME:
- PISTON KIT
MSRP: $105.95Now: $90.00Was: $105.95Qty in Cart: 0Quantity:Price:MSRP: $105.95Now: $90.00Was: $105.95Subtotal: -
On Sale
PROX Piston Kit 01.4223.A
PROX
MSRP: $101.95Now: $87.00Was: $101.95When your engine demands precision and reliability, OEM-spec pistons are non-negotiable. The PROX Piston Kit 01.4223.A delivers factory-matched performance with CNC-machined accuracy, ensuring consistent compression, reduced blow-by, and extended engine...09100024- SKU:
- 09100024
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- PISTON DIAMETER METRIC:
- 53.95 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- PISTON SIZE METRIC:
- STANDARD SIZE A
- BORE SIZE METRIC:
- 53.95 MM
- ENGINE TYPE:
- 2-STROKE
- RIDING STYLE:
- OFF-ROAD
MSRP: $101.95Now: $87.00Was: $101.95 -
On Sale
PROX Piston Kit 01.1414.A
PROX
MSRP: $210.95Now: $167.00Was: $210.95When your engine demands reliability under extreme conditions, OEM-spec pistons aren't optional—they're foundational. The PROX Piston Kit 01.1414.A delivers factory-engineered performance with precision machining that eliminates the guesswork of...09100607- SKU:
- 09100607
- Availability:
- Ships Same Business Day
- Weight:
- 0.81 LBS
- BORE SIZE METRIC:
- 95.96 MM
- PISTON DIAMETER METRIC:
- 95.96 MM
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- PISTON SIZE METRIC:
- STANDARD SIZE A
- RIDING STYLE:
- OFF-ROAD
MSRP: $210.95Now: $167.00Was: $210.95 -
On Sale
PROX Piston Kit 01.1338.B
PROX
MSRP: $188.95Now: $158.00Was: $188.95Worn or damaged pistons compromise engine efficiency, power delivery, and long-term reliability—especially under racing conditions or high-mileage operation. The PROX Piston Kit 01.1338.B restores your engine to OEM specification with...09101127- SKU:
- 09101127
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 77.98 MM
- BORE SIZE METRIC:
- 77.98 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
MSRP: $188.95Now: $158.00Was: $188.95 -
On Sale
PROX Piston Kit 01.1320.A2
PROX
MSRP: $139.95Now: $119.00Was: $139.95When your engine is the heartbeat of your vehicle, piston quality directly impacts reliability, power delivery, and longevity. The PROX Piston Kit 01.1320.A2 delivers OEM-equivalent performance without compromise, engineered with precision manufacturing...PX4430C- SKU:
- PX4430C
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 66.36 MM
- PISTON SIZE METRIC:
- STANDARD SIZE A
- BORE SIZE METRIC:
- 66.36 MM
- PRODUCT NAME:
- PISTON KIT
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
MSRP: $139.95Now: $119.00Was: $139.95Qty in Cart: 0Quantity:Price:MSRP: $139.95Now: $119.00Was: $139.95Subtotal: -
VERTEX Piston Kit 24220B
VERTEX
$269.95The VERTEX Piston Kit 24220B delivers the durability and precision your engine demands, whether you're pushing peak RPMs on the track or rebuilding after hard use. Built with advanced metallurgy and factory-grade coatings, these pistons reduce break-in...09105190- SKU:
- 09105190
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
- COMPRESSION RATIO IMPERIAL:
- 13.7:1
- DISPLACEMENT:
- 250 CC
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- FORGED HIGH COMPRESSION
- UNITS:
- KIT
- PISTON DIAMETER METRIC:
- 76.96 MM
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- PRODUCT NAME:
- PISTON KIT
- CYLINDER DIAMETER METRIC:
- 77.00 MM
- ENGINE TYPE:
- 4-STROKE
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
$269.95 -
VERTEX Piston Kit 24101A
VERTEX
$223.95The VERTEX Piston Kit 24101A delivers the precision engineering and durability demanded by serious racers and high-performance builders. Whether you're rebuilding a worn engine or pushing displacement and compression, this kit provides the exact...09104070- SKU:
- 09104070
- Availability:
- Ships Same Business Day
- Weight:
- 0.60 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- STYLE:
- CAST REPLICA
- DISPLACEMENT:
- 150 CC
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- PISTON KIT
- CYLINDER DIAMETER METRIC:
- 58 MM
- PISTON DIAMETER METRIC:
- 57.94 MM
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- PISTON MATERIAL:
- CAST
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$223.95 -
VERTEX Piston Kit 24097A
VERTEX
$302.95A piston kit is only as good as its metallurgy and surface treatment—and VERTEX's 24097A delivers on both fronts. The T-5 heat treatment cycle ensures consistent hardness and durability under extreme combustion pressures, while the Molybdenum Disulphite...09104076- SKU:
- 09104076
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
$302.95 -
VERTEX Piston Kit 24122B
VERTEX
$256.95Whether you're building a race engine or refreshing a high-mileage platform, piston durability is non-negotiable. The VERTEX Piston Kit 24122B delivers the material science and precision engineering needed to withstand sustained high-RPM operation and...09104087- SKU:
- 09104087
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
$256.95Qty in Cart: 0Quantity:Price:$256.95Subtotal: -
VERTEX Piston Kit - High Compression 24120C
VERTEX
$138.95High-compression pistons are essential for maximizing horsepower and torque output while maintaining reliability under extreme combustion pressures. The VERTEX 24120C kit delivers OEM-quality construction with race-proven durability, making it the go-to...09104099- SKU:
- 09104099
- Availability:
- Ships Same Business Day
- Weight:
- 0.60 LBS
- COMPRESSION RATIO IMPERIAL:
- 14.3:1
- DISPLACEMENT:
- 250 CC
- STYLE:
- FORGED HIGH COMPRESSION
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- PISTON KIT
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- CYLINDER DIAMETER METRIC:
- 76.80 MM
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 76.78 MM
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
$138.95Qty in Cart: 0Quantity:Price:$138.95Subtotal: -
VERTEX Piston Kit 24099A
VERTEX
$302.95If you're building or rebuilding an engine that demands reliability under extreme conditions, the VERTEX Piston Kit 24099A delivers the precision-engineered durability required for sustained high-RPM performance. The advanced T-5 heat treatment process...09104107- SKU:
- 09104107
- Availability:
- Ships Same Business Day
- Weight:
- 0.90 LBS
- CYLINDER DIAMETER METRIC:
- 95.00 MM
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- COMPRESSION RATIO IMPERIAL:
- 12.6:1
- ENGINE TYPE:
- 4-STROKE
- PISTON DIAMETER METRIC:
- 94.95 MM
- PRODUCT NAME:
- PISTON KIT
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- DISPLACEMENT:
- 450 CC
- RIDING STYLE:
- OFF-ROAD
- RIDING STYLE:
- STREET
- STYLE:
- FORGED HIGH COMPRESSION
- UNITS:
- KIT
$302.95 -
VERTEX Piston Kit 24099B
VERTEX
$302.95A piston kit is only as good as its metallurgy and surface treatment—this is where engine reliability lives or dies. The VERTEX Piston Kit 24099B delivers heat-treated construction and a molybdenum disulfide coating that reduce friction during critical...09104108- SKU:
- 09104108
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- CYLINDER DIAMETER METRIC:
- 95.00 MM
- PISTON DIAMETER METRIC:
- 94.96 MM
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- DISPLACEMENT:
- 450 CC
- COMPRESSION RATIO IMPERIAL:
- 12.6:1
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- STREET
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- FORGED HIGH COMPRESSION
- UNITS:
- KIT
$302.95
