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 01.3122.C
PROX
$94.95When your engine demands reliability that matches factory specifications, the PROX Piston Kit 01.3122.C delivers the precision engineering required for sustained high-performance operation. This complete kit eliminates the guesswork of sourcing...09100433- SKU:
- 09100433
- Availability:
- Ships Same Business Day
- Weight:
- 0.31 LBS
- PISTON DIAMETER METRIC:
- 47.96 MM
- BORE SIZE METRIC:
- 47.96 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE C
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$94.95Qty in Cart: 0Quantity:Price:$94.95Subtotal: -
PROX Piston Kit 01.3224.C
PROX
$105.95Your engine's heart depends on pistons that can withstand extreme pressure and temperature cycles without compromise. The PROX Piston Kit 01.3224.C delivers OEM-equivalent performance through precision Japanese manufacturing and high-silicon aluminum...09100436- SKU:
- 09100436
- Availability:
- Ships Same Business Day
- Weight:
- 0.56 LBS
- BORE SIZE METRIC:
- 53.97 MM
- PISTON SIZE METRIC:
- STANDARD SIZE C
- PRODUCT NAME:
- PISTON KIT
- PISTON DIAMETER METRIC:
- 53.97 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$105.95Qty in Cart: 0Quantity:Price:$105.95Subtotal: -
PROX Piston Kit 01.1343.A
PROX
$185.95When your engine demands reliable, OEM-matched performance, a quality piston kit is non-negotiable. The PROX Piston Kit 01.1343.A delivers factory-specification durability with precision CNC machining, ensuring consistent compression and minimal wear...09104533- SKU:
- 09104533
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
- BORE SIZE METRIC:
- 76.77 MM
- PRODUCT NAME:
- PISTON KIT
- PISTON DIAMETER METRIC:
- 76.77 MM
- PISTON SIZE METRIC:
- STANDARD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$185.95Qty in Cart: 0Quantity:Price:$185.95Subtotal: -
PROX Piston Kit 01.1346.B
PROX
$185.95When your engine's pistons show wear, you're losing compression, efficiency, and power output. The PROX Piston Kit 01.1346.B restores your engine to OEM specifications with precision-engineered components that match or exceed factory standards. This...09104537- SKU:
- 09104537
- Availability:
- Ships Same Business Day
- Weight:
- 0.45 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- BORE SIZE METRIC:
- 76.78 MM
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 76.78 MM
- PISTON SIZE METRIC:
- STANDARD
$185.95Qty in Cart: 0Quantity:Price:$185.95Subtotal: -
PROX Piston Kit 01.3341.B
PROX
$188.95A worn or damaged piston compromises compression, power delivery, and engine reliability—especially under high-performance conditions. The PROX Piston Kit 01.3341.B restores your engine to OEM specifications with precision-engineered components...09104540- SKU:
- 09104540
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- BORE SIZE METRIC:
- 76.97 MM
- RIDING STYLE:
- OFF-ROAD
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- PISTON DIAMETER METRIC:
- 76.97 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
$188.95 -
PROX Piston Kit 01.4342.C
PROX
$179.95When your engine demands reliability under extreme conditions, OEM-spec pistons are non-negotiable. The PROX Piston Kit 01.4342.C delivers factory-equivalent performance with precision Japanese manufacturing, ensuring consistent compression, minimal...09104544- SKU:
- 09104544
- Availability:
- Ships Same Business Day
- Weight:
- 0.45 LBS
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 76.98 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 76.98 MM
- RIDING STYLE:
- OFF-ROAD
$179.95Qty in Cart: 0Quantity:Price:$179.95Subtotal: -
PROX Piston Kit 01.6226.D
PROX
$143.95A piston failure or wear means catastrophic engine damage and costly downtime. The PROX Piston Kit 01.6226.D restores your engine to OEM specifications with precision-engineered components that deliver reliable performance across thousands of combustion...09104549- SKU:
- 09104549
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- RIDING STYLE:
- OFF-ROAD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 53.97 MM
- BORE SIZE METRIC:
- 53.97 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
$143.95 -
PROX Piston Kit 01.1232.B
PROX
$177.95Worn or damaged pistons rob your engine of compression, power, and reliability. The PROX Piston Kit 01.1232.B delivers OEM-equivalent performance with precision engineering that restores your engine to factory specifications—or beyond. Whether you're...09103252- SKU:
- 09103252
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 65.98 MM
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 65.98 MM
$177.95Qty in Cart: 0Quantity:Price:$177.95Subtotal: -
PROX Piston Kit 01.1413.A
PROX
$195.95When your engine demands precision and reliability, OEM-quality pistons are non-negotiable. The PROX Piston Kit 01.1413.A delivers factory-spec performance with Japanese engineering and CNC-machined accuracy, ensuring proper ring seal, optimal combustion...09103254- SKU:
- 09103254
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON DIAMETER METRIC:
- 95.96 MM
- UNITS:
- EACH
- PISTON SIZE METRIC:
- STANDARD
- BORE SIZE METRIC:
- 95.96 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- PISTON KIT
$195.95Qty in Cart: 0Quantity:Price:$195.95Subtotal: -
PROX Piston Kit 01.6394.C
PROX
$189.95When your engine demands reliability under extreme conditions, OEM-equivalent pistons are non-negotiable. The PROX Piston Kit 01.6394.C delivers Japanese manufacturing precision with a high-silicon aluminum alloy that meets or exceeds factory...09103259- SKU:
- 09103259
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
- BORE SIZE METRIC:
- 71.96 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- PISTON SIZE METRIC:
- STANDARD
- PISTON DIAMETER METRIC:
- 71.96 MM
- RIDING STYLE:
- OFF-ROAD
$189.95Qty in Cart: 0Quantity:Price:$189.95Subtotal: -
PROX Piston Kit 01.2414.C
PROX
$179.95When your engine's pistons show signs of wear or you're rebuilding after high-mileage service, choosing the right replacement is critical to maintaining peak performance and reliability. The PROX Piston Kit 01.2414.C delivers OEM-equivalent quality with...09103422- SKU:
- 09103422
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 76.97 MM
- PISTON DIAMETER METRIC:
- 76.97 MM
- RIDING STYLE:
- OFF-ROAD
$179.95Qty in Cart: 0Quantity:Price:$179.95Subtotal: -
PROX Piston Kit 01.6228.B
PROX
$139.95A piston kit is fundamental to engine reliability and performance—worn or damaged pistons compromise compression, fuel efficiency, and power delivery. The PROX Piston Kit 01.6228.B delivers OEM-specification quality without the OEM price tag, ensuring...09103438- SKU:
- 09103438
- Availability:
- Ships Same Business Day
- Weight:
- 0.45 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- BORE SIZE METRIC:
- 55.95 MM
- PISTON DIAMETER METRIC:
- 55.95 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
$139.95Qty in Cart: 0Quantity:Price:$139.95Subtotal: -
PROX Piston Kit 01.6228.C
PROX
$139.95Piston failure compromises engine reliability and performance—whether you're rebuilding after competition or restoring original capability. The PROX Piston Kit 01.6228.C delivers OEM-equivalent engineering with Japanese manufacturing precision, ensuring...09103439- SKU:
- 09103439
- Availability:
- Ships Same Business Day
- Weight:
- 0.45 LBS
- PISTON DIAMETER METRIC:
- 55.96 MM
- UNITS:
- EACH
- PISTON SIZE METRIC:
- STANDARD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 55.96 MM
- PRODUCT NAME:
- PISTON KIT
$139.95Qty in Cart: 0Quantity:Price:$139.95Subtotal: -
PROX Piston Kit - 300EXC TPI 01.6388.B
PROX
$189.95Your 300EXC TPI deserves piston internals that match factory precision without compromise. This OEM-spec replacement kit restores compression and reliability while maintaining the tight tolerances critical for forced-induction performance. Install with...09106267- SKU:
- 09106267
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$189.95Qty in Cart: 0Quantity:Price:$189.95Subtotal: -
PROX Piston Kit - Standard - Yamaha PW80 01.2008.000
PROX
$93.95The PROX Piston Kit delivers the reliability and precision your Yamaha PW80 demands in demanding off-road conditions. Factory-spec pistons ensure proper bore fit, ring sealing, and heat dissipation—critical for maintaining performance and engine...09106098- SKU:
- 09106098
- Availability:
- Ships Same Business Day
- Weight:
- 0.14 LBS
- BORE SIZE METRIC:
- 47.00 MM
- PRODUCT NAME:
- PISTON KIT
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$93.95Qty in Cart: 0Quantity:Price:$93.95Subtotal: -
PROX Piston Kit - Standard - KTM 125SX 01.6220.B
PROX
$124.95The PROX Piston Kit is engineered for the demanding demands of off-road racing, delivering the reliability and precision your KTM 125SX demands at high RPM. OEM pistons wear quickly under competition conditions—upgrading to PROX ensures consistent...09106107- SKU:
- 09106107
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE SIZE METRIC:
- 53.95 MM
- PRODUCT NAME:
- PISTON KIT
$124.95Qty in Cart: 0Quantity:Price:$124.95Subtotal: -
PROX Piston Kit - Standard - 200EXC 01.6249.B
PROX
$139.95The PROX Piston Kit maintains optimal compression and durability in high-demand off-road conditions, ensuring consistent performance lap after lap. Whether you're pushing your 200EXC to its limits on technical terrain or rebuilding after extensive use,...09106109- SKU:
- 09106109
- Availability:
- Ships Same Business Day
- Weight:
- 0.60 LBS
- BORE SIZE METRIC:
- 63.95 MM
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
$139.95Qty in Cart: 0Quantity:Price:$139.95Subtotal: -
On Sale
PROX Piston Kit 01.1323.C
PROX
MSRP: $139.95Now: $119.00Was: $139.95A piston kit is fundamental to engine reliability and performance—worn or damaged pistons compromise compression, increase blowby, and accelerate wear throughout your engine. The PROX Piston Kit 01.1323.C delivers OEM-equivalent performance with...PX1322C- SKU:
- PX1322C
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- RIDING STYLE:
- OFF-ROAD
- PISTON SIZE METRIC:
- STANDARD SIZE C
- BORE SIZE METRIC:
- 66.36 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 66.36 MM
MSRP: $139.95Now: $119.00Was: $139.95Qty in Cart: 0Quantity:Price:MSRP: $139.95Now: $119.00Was: $139.95Subtotal: -
On Sale
PROX Piston Kit 01.1208.A1
PROX
MSRP: $105.95Now: $90.00Was: $105.95When your engine's pistons wear beyond serviceable limits, you need a replacement that matches or exceeds OEM performance—not a compromise. The PROX Piston Kit 01.1208.A1 delivers factory-spec reliability with precision Japanese manufacturing, ensuring...PX4240B- SKU:
- PX4240B
- Availability:
- Ships Same Business Day
- Weight:
- 0.38 LBS
- PRODUCT NAME:
- PISTON KIT
- PISTON DIAMETER METRIC:
- 53.94 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 53.94 MM
- 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: -
On Sale
PROX Piston Kit 01.4108.B
PROX
MSRP: $89.95Now: $76.00Was: $89.95A worn or damaged piston compromises combustion efficiency, reduces power output, and risks catastrophic engine failure. The PROX Piston Kit 01.4108.B delivers OEM-equivalent performance with precision engineering that restores your engine to factory...PX4280B- SKU:
- PX4280B
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- PISTON DIAMETER METRIC:
- 47.95 MM
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE B
- UNITS:
- EACH
- BORE SIZE METRIC:
- 47.95 MM
- PRODUCT NAME:
- PISTON KIT
MSRP: $89.95Now: $76.00Was: $89.95Qty in Cart: 0Quantity:Price:MSRP: $89.95Now: $76.00Was: $89.95Subtotal:
