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 01.4413.B
PROX
$210.95A piston kit is mission-critical for any engine rebuild or high-mileage refresh—it's the component that directly translates combustion pressure into power, so quality here impacts reliability and...09103267- SKU:
- 09103267
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- PISTON DIAMETER METRIC:
- 95.98 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- BORE SIZE METRIC:
- 95.98 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
$210.95 -
PROX Piston Kit 01.4413.C
PROX
$189.95A piston kit is fundamental to engine longevity and performance—it directly impacts combustion efficiency, ring seal, and heat dissipation. The PROX Piston Kit 01.4413.C delivers OEM-quality...09103268- SKU:
- 09103268
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- PISTON DIAMETER METRIC:
- 95.99 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- BORE SIZE METRIC:
- 95.99 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
$189.95Qty in Cart: 0Quantity:Price:$189.95Subtotal: -
PROX Piston Kit 01.6019.B
PROX
$77.95A piston kit is the heart of your engine's combustion cycle—and worn or damaged pistons directly rob you of compression, power, and reliability. The PROX Piston Kit 01.6019.B delivers OEM-equivalent...09103270- SKU:
- 09103270
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- PISTON DIAMETER METRIC:
- 39.47 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 39.47 MM
$77.95 -
PROX Piston Kit 01.6019.C
PROX
$77.95A piston kit is critical to engine reliability and performance—worn or damaged pistons compromise compression, increase blow-by, and accelerate engine wear. The PROX Piston Kit 01.6019.C delivers...09103271- SKU:
- 09103271
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- BORE SIZE METRIC:
- 39.48 MM
- PISTON DIAMETER METRIC:
- 39.48 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD
- RIDING STYLE:
- OFF-ROAD
$77.95 -
PROX Piston Kit - 71.94 TM300 01.7302.A
PROX
$221.95When your engine has logged serious hours, piston wear directly compromises compression, fuel efficiency, and power output. The PROX Piston Kit 71.94 TM300 delivers OEM-equivalent performance with...09103287- SKU:
- 09103287
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- PRODUCT NAME:
- PISTON KIT
- PISTON DIAMETER METRIC:
- 71.94 MM
- ENGINE TYPE:
- 2-STROKE
- SKIRT COATING:
- MOLY COATED
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$221.95 -
PROX Piston Kit 01.2414.B
PROX
$179.95When you're rebuilding an engine, piston quality directly impacts reliability, longevity, and performance. The PROX Piston Kit 01.2414.B delivers OEM-equivalent engineering with Japanese...09103421- SKU:
- 09103421
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON DIAMETER METRIC:
- 76.96 MM
- UNITS:
- EACH
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 76.96 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
$179.95Qty in Cart: 0Quantity:Price:$179.95Subtotal: -
PROX Piston Kit 01.2444.A
PROX
$195.95When your engine demands peak performance and reliability, OEM-quality pistons are non-negotiable. The PROX Piston Kit 01.2444.A delivers factory-spec durability with precision engineering, ensuring...09103423- SKU:
- 09103423
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON DIAMETER METRIC:
- 96.95 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 96.95 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- OFF-ROAD
$195.95Qty in Cart: 0Quantity:Price:$195.95Subtotal: -
PROX Piston Kit 01.2444.B
PROX
$195.95A worn or damaged piston compromises combustion efficiency, reliability, and overall engine performance. The PROX Piston Kit 01.2444.B delivers OEM-equivalent performance with precision engineering,...09103424- SKU:
- 09103424
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- BORE SIZE METRIC:
- 96.96 MM
- PISTON SIZE METRIC:
- STANDARD
- ENGINE TYPE:
- 4-STROKE
- PISTON DIAMETER METRIC:
- 96.96 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
$195.95Qty in Cart: 0Quantity:Price:$195.95Subtotal: -
PROX Piston Kit 01.4124.A
PROX
$99.95A worn or damaged piston is a silent killer of engine performance and reliability. The PROX Piston Kit 01.4124.A restores your engine to OEM specifications with precision-engineered components that...09103429- SKU:
- 09103429
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 48.45 MM
- PISTON DIAMETER METRIC:
- 48.45 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$99.95 -
PROX Piston Kit 01.4124.B
PROX
$99.95When your engine's original pistons show signs of wear, ring blow-by, or loss of compression, a quality replacement kit is essential to restore reliability and performance. The PROX Piston Kit 01...09103430- SKU:
- 09103430
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- PISTON DIAMETER METRIC:
- 48.46 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 48.46 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$99.95 -
PROX Piston Kit 01.4124.C
PROX
$99.95A piston kit is the heart of your engine's combustion cycle—worn or damaged pistons directly compromise compression, power delivery, and reliability. The PROX Piston Kit 01.4124.C delivers...09103431- SKU:
- 09103431
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- PISTON DIAMETER METRIC:
- 48.47 MM
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 48.47 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- PISTON SIZE METRIC:
- STANDARD
- UNITS:
- EACH
$99.95 -
PROX Piston Kit - Beta RR300 01.7393.A
PROX
$199.95When your Beta RR300 demands peak performance, compromised pistons will cost you both power and reliability. This PROX piston kit delivers OEM-grade precision and durability with CNC-machined...09103447- SKU:
- 09103447
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- SKIRT COATING:
- MOLY COATED
- ENGINE TYPE:
- 2-STROKE
- PISTON DIAMETER METRIC:
- 71.94 MM
$199.95 -
PROX Piston Kit 01.6029.B
PROX
$77.95When your engine demands precision and reliability, OEM-specification pistons are non-negotiable. The PROX Piston Kit 01.6029.B delivers factory-grade performance with the durability required for...09102483- SKU:
- 09102483
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- BORE SIZE METRIC:
- 44.97 MM
- PISTON SIZE METRIC:
- STANDARD
- PISTON DIAMETER METRIC:
- 44.97 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
$77.95 -
PROX Piston Kit 01.6029.C
PROX
$77.95A piston kit is the heart of your engine's combustion cycle—when it fails or wears, you lose compression, power, and reliability. The PROX Piston Kit 01.6029.C delivers OEM-quality replacement...09102484- SKU:
- 09102484
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- PISTON DIAMETER METRIC:
- 44.98 MM
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 44.98 MM
- PISTON SIZE METRIC:
- STANDARD
- RIDING STYLE:
- OFF-ROAD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
$77.95 -
PROX Piston Kit 01.4345.A
PROX
$179.95Factory-spec piston performance requires precision manufacturing and material integrity—two areas where OEM replacements often fall short. The PROX Piston Kit 01.4345.A delivers exact OEM dimensions...09103904- SKU:
- 09103904
- Availability:
- Ships Same Business Day
- Weight:
- 0.45 LBS
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 76.96 MM
- PISTON DIAMETER METRIC:
- 76.96 MM
- RIDING STYLE:
- OFF-ROAD
$179.95Qty in Cart: 0Quantity:Price:$179.95Subtotal: -
PROX Piston Kit 01.4345.B
PROX
$179.95When your engine demands reliability under extreme combustion pressures, OEM-equivalent pistons are non-negotiable. The PROX Piston Kit 01.4345.B delivers the precision and durability of factory-spec...09103905- SKU:
- 09103905
- Availability:
- Ships Same Business Day
- Weight:
- 0.45 LBS
- PISTON DIAMETER METRIC:
- 76.97 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 76.97 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
$179.95Qty in Cart: 0Quantity:Price:$179.95Subtotal: -
PROX Piston Kit 01.4345.C
PROX
$179.95A piston kit is fundamental to engine reliability and performance—it directly impacts compression, combustion efficiency, and overall durability under load. The PROX Piston Kit 01.4345.C delivers...09103906- SKU:
- 09103906
- Availability:
- Ships Same Business Day
- Weight:
- 0.45 LBS
- BORE SIZE METRIC:
- 76.98 MM
- PISTON SIZE METRIC:
- STANDARD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 76.98 MM
- RIDING STYLE:
- OFF-ROAD
$179.95 -
PROX Piston Kit 01.4415.C
PROX
$189.95A worn or damaged piston directly compromises engine compression, power delivery, and longevity—requiring immediate replacement to restore factory performance and reliability. The PROX Piston Kit 01...09103909- SKU:
- 09103909
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- PISTON DIAMETER METRIC:
- 95.99 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 95.99 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
$189.95Qty in Cart: 0Quantity:Price:$189.95Subtotal: -
PROX Piston Kit 01.2412.B
PROX
$179.95When your engine demands reliability at high RPM, factory pistons often can't deliver the precision fit and durability required for sustained performance. The PROX Piston Kit 01.2412.B is engineered...09102733- SKU:
- 09102733
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 76.96 MM
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 76.96 MM
- RIDING STYLE:
- OFF-ROAD
$179.95Qty in Cart: 0Quantity:Price:$179.95Subtotal: -
PROX Piston - SuperJet 700 01.2510.100
PROX
$129.95The PROX Piston for SuperJet 700 delivers the reliability and precision your watercraft demands during high-performance operation. A quality piston is critical to maintaining compression, power...09102740- SKU:
- 09102740
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
- ENGINE TYPE:
- 2-STROKE
- BORE SIZE METRIC:
- 82.00 MM
- PISTON MATERIAL:
- ALUMINUM
- UNITS:
- EACH
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- WATERCRAFT
$129.95
