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 01.4213.C
PROX
MSRP: $105.95Now: $90.00Was: $105.95Stock pistons wear out, and when they do, your engine's compression, power delivery, and reliability suffer. The PROX Piston Kit 01.4213.C delivers OEM-equivalent performance with Japanese manufacturing precision, ensuring your engine operates at peak...PX4294C- SKU:
- PX4294C
- Availability:
- Ships Same Business Day
- Weight:
- 0.38 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE C
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- BORE SIZE METRIC:
- 53.96 MM
- PISTON DIAMETER METRIC:
- 53.96 MM
- 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 01.1315.A1
PROX
MSRP: $139.95Now: $119.00Was: $139.95Whether you're rebuilding after race-induced wear or restoring your engine to factory performance, the PROX Piston Kit 01.1315.A1 delivers the precision and durability that competitive engines demand. These pistons are engineered to OEM specifications...PX4420B- SKU:
- PX4420B
- Availability:
- Ships Same Business Day
- Weight:
- 0.63 LBS
- PISTON DIAMETER METRIC:
- 66.35 MM
- PISTON SIZE METRIC:
- STANDARD SIZE A
- RIDING STYLE:
- OFF-ROAD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 66.35 MM
- PRODUCT NAME:
- PISTON KIT
MSRP: $139.95Now: $119.00Was: $139.95 -
On Sale
PROX Piston Kit 01.1315.A2
PROX
MSRP: $139.95Now: $119.00Was: $139.95A piston kit is the heart of engine reliability—worn or damaged pistons compromise combustion efficiency, increase blowby, and accelerate engine degradation. The PROX Piston Kit 01.1315.A2 restores OEM-specification performance with precision-engineered...PX4420C- SKU:
- PX4420C
- Availability:
- Ships Same Business Day
- Weight:
- 0.63 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- BORE SIZE METRIC:
- 66.36 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- PISTON SIZE METRIC:
- STANDARD SIZE A
- PISTON DIAMETER METRIC:
- 66.36 MM
- PRODUCT NAME:
- PISTON KIT
MSRP: $139.95Now: $119.00Was: $139.95Qty in Cart: 0Quantity:Price:MSRP: $139.95Now: $119.00Was: $139.95Subtotal: -
On Sale
PROX Piston Kit 01.1315.A3
PROX
MSRP: $139.95Now: $119.00Was: $139.95When your engine is running at the limit, piston failure isn't an option. The PROX Piston Kit 01.1315.A3 delivers OEM-equivalent reliability with the precision engineering required for high-performance applications. This complete kit ensures you have...PX4420D- SKU:
- PX4420D
- Availability:
- Ships Same Business Day
- Weight:
- 0.63 LBS
- PISTON SIZE METRIC:
- STANDARD SIZE A
- PISTON DIAMETER METRIC:
- 66.37 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- BORE SIZE METRIC:
- 66.37 MM
- PRODUCT NAME:
- PISTON KIT
MSRP: $139.95Now: $119.00Was: $139.95Qty in Cart: 0Quantity:Price:MSRP: $139.95Now: $119.00Was: $139.95Subtotal: -
On Sale
PROX Piston Kit 01.1320.A3
PROX
MSRP: $139.95Now: $119.00Was: $139.95When your engine demands reliability under extreme conditions, OEM-specification pistons are non-negotiable. The PROX Piston Kit 01.1320.A3 delivers the precision engineering and material integrity required for consistent performance, whether you're...PX4430D- SKU:
- PX4430D
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- PISTON SIZE METRIC:
- STANDARD SIZE A
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 66.37 MM
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 66.37 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
MSRP: $139.95Now: $119.00Was: $139.95Qty in Cart: 0Quantity:Price:MSRP: $139.95Now: $119.00Was: $139.95Subtotal: -
On Sale
PROX Piston Kit 01.3310.D
PROX
MSRP: $129.95Now: $110.00Was: $129.95When your engine's pistons wear beyond their limits, you're looking at catastrophic performance loss and potential internal damage. The PROX Piston Kit 01.3310.D delivers OEM-equivalent reliability with precision engineering, restoring your engine to...PX5070D- SKU:
- PX5070D
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- PISTON DIAMETER METRIC:
- 66.96 MM
- PISTON SIZE METRIC:
- STANDARD SIZE D
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 66.96 MM
- PRODUCT NAME:
- PISTON KIT
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
MSRP: $129.95Now: $110.00Was: $129.95Qty in Cart: 0Quantity:Price:MSRP: $129.95Now: $110.00Was: $129.95Subtotal: -
On Sale
PROX Piston Kit 01.3310.E
PROX
MSRP: $129.95Now: $110.00Was: $129.95When your engine's internals are worn or damaged, OEM-quality replacement pistons are essential for restoring compression, reliability, and performance. The PROX Piston Kit 01.3310.E delivers factory-spec precision without the factory price tag, giving...PX5070E- SKU:
- PX5070E
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- PISTON DIAMETER METRIC:
- 66.97 MM
- PISTON SIZE METRIC:
- STANDARD SIZE E
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 66.97 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
MSRP: $129.95Now: $110.00Was: $129.95Qty in Cart: 0Quantity:Price:MSRP: $129.95Now: $110.00Was: $129.95Subtotal: -
On Sale
PROX Piston Kit 01.2217.D
PROX
MSRP: $121.95Now: $90.00Was: $121.95Worn or damaged pistons compromise engine efficiency, power delivery, and reliability—making a quality replacement essential for any serious build or rebuild. The PROX Piston Kit 01.2217.D delivers OEM-equivalent performance with the precision...PX7215D- SKU:
- PX7215D
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- BORE SIZE METRIC:
- 53.98 MM
- PISTON DIAMETER METRIC:
- 53.98 MM
- PISTON SIZE METRIC:
- STANDARD
MSRP: $121.95Now: $90.00Was: $121.95 -
On Sale
PROX Piston Kit 01.1218.A3
PROX
MSRP: $105.95Now: $90.00Was: $105.95Over time, pistons experience wear that compromises compression, increases blow-by, and reduces engine efficiency—ultimately costing you power and reliability. The PROX Piston Kit 011218A3 restores your engine to OEM specifications with...PX4260C- SKU:
- PX4260C
- Availability:
- Ships Same Business Day
- Weight:
- 0.38 LBS
- PISTON DIAMETER METRIC:
- 53.96 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 53.96 MM
- PRODUCT NAME:
- PISTON KIT
- PISTON SIZE METRIC:
- STANDARD SIZE A
- RIDING STYLE:
- OFF-ROAD
MSRP: $105.95Now: $90.00Was: $105.95Qty in Cart: 0Quantity:Price:MSRP: $105.95Now: $90.00Was: $105.95Subtotal: -
VERTEX Piston Kit - High Compression 24123A
VERTEX
$260.95High-compression pistons are essential if you're pushing your engine beyond stock parameters—whether that's aggressive boost levels, high-RPM builds, or naturally aspirated displacement increases. The VERTEX 24123A kit delivers the durability and...09104100- SKU:
- 09104100
- Availability:
- Ships Same Business Day
- Weight:
- 0.60 LBS
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- FORGED HIGH COMPRESSION
- UNITS:
- KIT
- COMPRESSION RATIO IMPERIAL:
- 14.2:1
- DISPLACEMENT:
- 250 CC
- ENGINE TYPE:
- 4-STROKE
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- CYLINDER DIAMETER METRIC:
- 77.00 MM
- PISTON DIAMETER METRIC:
- 76.95 MM
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- PRODUCT NAME:
- PISTON KIT
$260.95Qty in Cart: 0Quantity:Price:$260.95Subtotal: -
VERTEX Piston Kit - High Compression 24112A
VERTEX
$327.95High-compression pistons are critical for maximizing power output and engine efficiency in forced-induction and naturally-aspirated builds, and the VERTEX 24112A delivers the durability and precision needed for sustained high-RPM operation. This kit...09104113- SKU:
- 09104113
- Availability:
- Ships Same Business Day
- Weight:
- 0.90 LBS
- COMPRESSION RATIO IMPERIAL:
- 13.6:1
- DISPLACEMENT:
- 450 CC
- PRODUCT NAME:
- PISTON KIT
- CYLINDER DIAMETER METRIC:
- 95.00 MM
- PISTON DIAMETER METRIC:
- 94.95 MM
- RIDING STYLE:
- STREET
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- FORGED HIGH COMPRESSION
- UNITS:
- KIT
$327.95 -
VERTEX Piston Kit VTK22995B
VERTEX
$197.95Precision-engineered pistons are the foundation of reliable high-RPM performance, and the VERTEX Piston Kit VTK22995B delivers the durability and longevity required for sustained racing and demanding engine builds. The advanced T-5 heat treatment process...09103020- SKU:
- 09103020
- Availability:
- Ships Same Business Day
- Weight:
- 0.90 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- CYLINDER DIAMETER METRIC:
- 54.00 MM
- PRODUCT NAME:
- TOP END PISTON KIT
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- CAST REPLICA
- DISPLACEMENT:
- 125 CC
- ENGINE TYPE:
- 2-STROKE
- PISTON DIAMETER METRIC:
- 53.93 MM
- PISTON MATERIAL:
- CAST
- UNITS:
- KIT
$197.95 -
VERTEX Piston Kit 23335A
VERTEX
$197.95Premium pistons are the foundation of any high-performance engine build, and the VERTEX Piston Kit 23335A delivers the durability and precision needed for sustained power output and reliable operation under extreme conditions. The advanced heat-treatment...09100967- SKU:
- 09100967
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- PRODUCT NAME:
- PISTON KIT
- BORE - OVERSIZE:
- +4,00 MM
- BORE - OVERSIZE METRIC:
- +4.00 MM
- DISPLACEMENT:
- 144 CC
- PISTON MATERIAL:
- CAST
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- CAST BIG BORE
- UNITS:
- KIT
- ENGINE TYPE:
- 2-STROKE
- PISTON DIAMETER METRIC:
- 57.95 MM
- COMPRESSION RATIO IMPERIAL:
- STANDARD
- CYLINDER DIAMETER METRIC:
- 58.00 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
$197.95 -
VERTEX Piston Kit 22951A
VERTEX
$262.95A quality piston kit is the foundation of engine reliability and performance—whether you're rebuilding after wear or upgrading for more power. The VERTEX Piston Kit 22951A delivers OEM-grade construction with forged 2618 aluminum and proven durability...09100978- SKU:
- 09100978
- Availability:
- Ships Same Business Day
- Weight:
- 0.94 LBS
$262.95Qty in Cart: 0Quantity:Price:$262.95Subtotal: -
VERTEX Piston Kit 24275B
VERTEX
$322.95Whether you're rebuilding a two-stroke or refreshing a four-stroke top end, the VERTEX Piston Kit 24275B delivers the precision and durability required for consistent performance across your entire RPM range. VERTEX pistons are engineered with advanced...09105132- SKU:
- 09105132
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- COMPRESSION RATIO IMPERIAL:
- 14.2:1
- DISPLACEMENT:
- 250 CC
- PISTON DIAMETER METRIC:
- 78.97 MM
- CYLINDER DIAMETER METRIC:
- 79 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- PRODUCT NAME:
- PISTON KIT
- STYLE:
- GP RACER'S CHOICE
- ENGINE TYPE:
- 4-STROKE
- SKIRT COATING:
- MOLYBDENUM DISULPHITE
$322.95 -
VERTEX Piston Kit 24196A
VERTEX
$271.95The VERTEX Piston Kit 24196A delivers the durability and precision your engine demands, whether you're pushing peak RPMs on the track or rebuilding a worn top end. Engineered with premium materials and advanced surface treatments, these pistons are...09105140- SKU:
- 09105140
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
$271.95Qty in Cart: 0Quantity:Price:$271.95Subtotal: -
VERTEX Piston Kit 24196B
VERTEX
$302.95The VERTEX Piston Kit 24196B delivers the durability and precision you need for high-RPM reliability, whether you're building a race engine or restoring a well-loved machine. The molybdenum disulfide coating on each piston skirt accelerates break-in...09105141- SKU:
- 09105141
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
$302.95Qty in Cart: 0Quantity:Price:$302.95Subtotal: -
VERTEX Piston Kit VTKTC22805A
VERTEX
$315.95A quality piston kit is the foundation of reliable engine performance, and VERTEX's VTKTC22805A delivers the durability and precision that serious builders demand. The proprietary T-5 heat treatment cycle ensures consistent hardness and strength across...09103703- SKU:
- 09103703
- Availability:
- Ships Same Business Day
- Weight:
- 1.85 LBS
$315.95Qty in Cart: 0Quantity:Price:$315.95Subtotal: -
VERTEX Piston Kit VTKTC22805B
VERTEX
$315.95A high-revving engine demands pistons engineered for sustained performance under extreme conditions. The VERTEX Piston Kit VTKTC22805B delivers the durability and precision needed to handle aggressive boost levels, extended track sessions, and sustained...09103704- SKU:
- 09103704
- Availability:
- Ships Same Business Day
- Weight:
- 1.65 LBS
$315.95Qty in Cart: 0Quantity:Price:$315.95Subtotal: -
VERTEX Piston Kit - High Compression VTKTC22900B
VERTEX
$388.95The VERTEX Piston Kit delivers the thermal stability and durability required for sustained high-RPM operation in competition and street applications. With precision engineering and advanced surface treatments, these pistons reduce friction during...09103709- SKU:
- 09103709
- Availability:
- Ships Same Business Day
- Weight:
- 2.45 LBS
$388.95
