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 01.4223.B
PROX
$105.95Manufactured 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,...09100025- SKU:
- 09100025
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON DIAMETER METRIC:
- 53.96 MM
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 2-STROKE
- PISTON SIZE METRIC:
- STANDARD SIZE B
- UNITS:
- EACH
- BORE SIZE METRIC:
- 53.96 MM
- PRODUCT NAME:
- PISTON KIT
$105.95 -
PROX Piston Kit 01.4223.C
PROX
$101.95Manufactured 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,...09100026- SKU:
- 09100026
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- BORE SIZE METRIC:
- 53.97 MM
- PISTON SIZE METRIC:
- STANDARD SIZE C
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 53.97 MM
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- PISTON KIT
$101.95 -
PROX Piston Kit 01.2406.A
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,...09100027- SKU:
- 09100027
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- PISTON DIAMETER METRIC:
- 76.95 MM
- BORE SIZE METRIC:
- 76.95 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
$179.95 -
PROX Piston Kit 01.2406.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,...09100028- SKU:
- 09100028
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- BORE SIZE METRIC:
- 76.96 MM
- ENGINE TYPE:
- 4-STROKE
- PISTON DIAMETER METRIC:
- 76.96 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- PISTON SIZE METRIC:
- STANDARD SIZE B
- RIDING STYLE:
- OFF-ROAD
$179.95 -
PROX Piston Kit 01.2427.A
PROX
$185.95Manufactured 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,...09100031- SKU:
- 09100031
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- BORE SIZE METRIC:
- 94.95 MM
- PISTON SIZE METRIC:
- STANDARD SIZE A
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 4-STROKE
- PISTON DIAMETER METRIC:
- 94.95 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
$185.95 -
PROX Piston Kit - KDX200 '86-'06 01.4285.D
PROX
$129.95Manufactured 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,...09101453- SKU:
- 09101453
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- PISTON DIAMETER METRIC:
- 65.97 MM
- PRODUCT NAME:
- PISTON KIT
- PISTON MATERIAL:
- ALUMINUM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- ENGINE TYPE:
- 2-STROKE
- SKIRT COATING:
- MOLY COATED
$129.95 -
PROX Piston Kit 01.4409.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,...09101465- SKU:
- 09101465
- Availability:
- Ships Same Business Day
- Weight:
- 0.82 LBS
- RIDING STYLE:
- OFF-ROAD
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- BORE SIZE METRIC:
- 95.97 MM
- PISTON SIZE METRIC:
- STANDARD SIZE A
- PISTON DIAMETER METRIC:
- 95.97 MM
$189.95 -
PROX Piston Kit 01.4409.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,...09101466- SKU:
- 09101466
- Availability:
- Ships Same Business Day
- Weight:
- 0.85 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE B
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- BORE SIZE METRIC:
- 95.98 MM
- PRODUCT NAME:
- PISTON KIT
- PISTON DIAMETER METRIC:
- 95.98 MM
$189.95Qty in Cart: 0Quantity:Price:$189.95Subtotal: -
PROX Piston Kit 01.6604.B
PROX
$229.95Manufactured 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,...09101524- SKU:
- 09101524
- Availability:
- Ships Same Business Day
- Weight:
- 1.16 LBS
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- OFF-ROAD
- PISTON SIZE METRIC:
- STANDARD SIZE B
- UNITS:
- EACH
- BORE SIZE METRIC:
- 100.95 MM
- PISTON DIAMETER METRIC:
- 100.95 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
$229.95 -
PROX Piston Kit 01.2409.A
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,...09101609- SKU:
- 09101609
- Availability:
- Ships Same Business Day
- Weight:
- 0.54 LBS
- BORE SIZE METRIC:
- 76.95 MM
- PRODUCT NAME:
- PISTON KIT
- PISTON DIAMETER METRIC:
- 76.95 MM
- PISTON SIZE METRIC:
- STANDARD SIZE A
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$179.95 -
PROX Piston Kit 01.1338.A
PROX
$185.95Manufactured 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,...09101126- SKU:
- 09101126
- Availability:
- Ships Same Business Day
- Weight:
- 0.49 LBS
- BORE SIZE METRIC:
- 77.97 MM
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 77.97 MM
- RIDING STYLE:
- OFF-ROAD
$185.95 -
PROX Piston Kit 01.1338.C
PROX
$185.95Manufactured 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,...09101128- SKU:
- 09101128
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- ENGINE TYPE:
- 4-STROKE
- BORE SIZE METRIC:
- 77.99 MM
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 77.99 MM
- PISTON SIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON KIT
$185.95 -
PROX Piston Kit 01.1339.B
PROX
$185.95Manufactured 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,...09101130- SKU:
- 09101130
- Availability:
- Ships Same Business Day
- Weight:
- 0.49 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- ENGINE TYPE:
- 4-STROKE
- PISTON DIAMETER METRIC:
- 77.98 MM
- PISTON SIZE METRIC:
- STANDARD SIZE B
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 77.98 MM
- PRODUCT NAME:
- PISTON KIT
$185.95 -
PROX Piston Kit 01.2406.C
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,...09101133- SKU:
- 09101133
- Availability:
- Ships Same Business Day
- Weight:
- 0.57 LBS
- PISTON DIAMETER METRIC:
- 76.97 MM
- BORE SIZE METRIC:
- 76.97 MM
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- PISTON SIZE METRIC:
- STANDARD SIZE A
- PRODUCT NAME:
- PISTON KIT
$179.95 -
PROX Piston Kit 01.2427.C
PROX
$185.95Manufactured 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,...09101139- SKU:
- 09101139
- Availability:
- Ships Same Business Day
- Weight:
- 0.86 LBS
- PRODUCT NAME:
- PISTON KIT
- PISTON DIAMETER METRIC:
- 94.97 MM
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 94.97 MM
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE C
- UNITS:
- EACH
$185.95 -
PROX Piston Kit 01.3338.A
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,...09101145- SKU:
- 09101145
- Availability:
- Ships Same Business Day
- Weight:
- 0.48 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- BORE SIZE METRIC:
- 76.96 MM
- PISTON SIZE METRIC:
- STANDARD SIZE A
- PISTON DIAMETER METRIC:
- 76.96 MM
- PRODUCT NAME:
- PISTON KIT
$179.95 -
PROX Piston Kit 01.3338.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,...09101146- SKU:
- 09101146
- Availability:
- Ships Same Business Day
- Weight:
- 0.48 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 76.97 MM
- PISTON SIZE METRIC:
- STANDARD SIZE B
- BORE SIZE METRIC:
- 76.97 MM
- PRODUCT NAME:
- PISTON KIT
$179.95 -
PROX Piston Kit 01.3410.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,...09101148- SKU:
- 09101148
- Availability:
- Ships Same Business Day
- Weight:
- 0.82 LBS
- BORE SIZE METRIC:
- 95.47 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 95.47 MM
- RIDING STYLE:
- OFF-ROAD
- PISTON SIZE METRIC:
- STANDARD SIZE A
- PRODUCT NAME:
- PISTON KIT
$189.95 -
PROX Piston Kit 01.3410.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,...09101149- SKU:
- 09101149
- Availability:
- Ships Same Business Day
- Weight:
- 0.83 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE B
- UNITS:
- EACH
- BORE SIZE METRIC:
- 95.48 MM
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 95.48 MM
- PRODUCT NAME:
- PISTON KIT
$189.95 -
PROX Piston Kit 01.3410.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,...09101150- SKU:
- 09101150
- Availability:
- Ships Same Business Day
- Weight:
- 0.82 LBS
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 95.49 MM
- PISTON DIAMETER METRIC:
- 95.49 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE C
- UNITS:
- EACH
$189.95
