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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PROX Piston Kit 01.6226.A
PROX
$124.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...09104546- SKU:
- 09104546
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 53.94 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 53.94 MM
$124.95 -
PROX Piston Kit 01.6226.B
PROX
$124.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...09104547- SKU:
- 09104547
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- PISTON SIZE METRIC:
- STANDARD
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 53.95 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- BORE SIZE METRIC:
- 53.95 MM
$124.95 -
PROX Piston Kit 01.6226.C
PROX
$124.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...09104548- SKU:
- 09104548
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- PISTON DIAMETER METRIC:
- 53.96 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 53.96 MM
$124.95 -
PROX Piston Kit - MX/EC250 01.7307.B
PROX
$159.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...09103246- SKU:
- 09103246
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- SKIRT COATING:
- MOLY COATED
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- ENGINE TYPE:
- 2-STROKE
- PISTON DIAMETER METRIC:
- 66.34 MM
- PRODUCT NAME:
- PISTON KIT
$159.95 -
PROX Piston Kit - 71.94 EC300 01.7300.A
PROX
$199.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...09103248- SKU:
- 09103248
- Availability:
- Ships Same Business Day
- Weight:
- 0.70 LBS
- PISTON DIAMETER METRIC:
- 71.94 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ATV
- RIDING STYLE:
- STREET
- PISTON MATERIAL:
- ALUMINUM ALLOY
- SKIRT COATING:
- MOLY COATED
$199.95 -
PROX Piston Kit 01.6394.A
PROX
$189.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...09103257- SKU:
- 09103257
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 71.94 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 71.94 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
$189.95 -
PROX Piston Kit 01.6394.B
PROX
$189.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...09103258- SKU:
- 09103258
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
- BORE SIZE METRIC:
- 71.95 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- PISTON DIAMETER METRIC:
- 71.95 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
$189.95 -
PROX Piston Kit 01.4413.A
PROX
$189.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...09103266- SKU:
- 09103266
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- PISTON DIAMETER METRIC:
- 95.97 MM
- PISTON SIZE METRIC:
- STANDARD
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 95.97 MM
- PRODUCT NAME:
- PISTON KIT
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
$189.95 -
PROX Piston Kit 01.4413.B
PROX
$189.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...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
$189.95 -
PROX Piston Kit 01.4413.C
PROX
$189.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...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
$189.95 -
PROX Piston Kit 01.6019.B
PROX
$59.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...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
$59.95 -
PROX Piston Kit 01.6019.C
PROX
$59.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...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
$59.95 -
PROX Piston Kit - 71.94 TM300 01.7302.A
PROX
$199.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...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
$199.95 -
PROX Piston Kit 01.2414.B
PROX
$179.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...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
$179.95 -
PROX Piston Kit 01.2444.A
PROX
$195.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...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
$195.95 -
PROX Piston Kit 01.2444.B
PROX
$195.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...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
$195.95 -
PROX Piston Kit 01.4124.A
PROX
$94.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...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
$94.95 -
PROX Piston Kit 01.4124.B
PROX
$94.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...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
$94.95 -
PROX Piston Kit 01.4124.C
PROX
$94.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...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
$94.95 -
PROX Piston Kit - Beta RR300 01.7393.A
PROX
$199.95Manufactured in Japan and designed to be OEM replacement, Cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications, then CNC-machined to extremely close tolerances, Pistons supplied in a kit package that includes rings,...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
