Dirt Bike Engine
Dirt Bike Engine Parts at JJ Motorsports
Discover a full range of dirt bike engine components for rebuilding or upgrading your performance from JJ Motorsports. From crankshafts to cylinder heads and piston kits, these precision-engineered components ensure reliable performance. For additional upgrades, check out our full selection of off-road dirt bike parts to keep your engine running at peak efficiency on the track or trails.
Shop trusted brands like Wiseco for forged piston kits and K&N for high-flow oil filters. Explore related categories such as Dirt Bike Air and Fuel for intake upgrades or Dirt Bike Exhaust for complete systems.
Browse our in-stock inventory below with same-day shipping and expert support. Questions? Contact us for fitment advice!
- Product
- Qty in Cart
- Quantity
- Price
- Subtotal
-
On Sale
PROX Piston Kit 01.1339.A
PROX
MSRP: $185.95Now: $158.00Was: $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,...09101129- SKU:
- 09101129
- Availability:
- Ships Same Business Day
- Weight:
- 0.49 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON DIAMETER METRIC:
- 77.97 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- PRODUCT NAME:
- PISTON KIT
- PISTON SIZE METRIC:
- STANDARD SIZE A
- BORE SIZE METRIC:
- 77.97 MM
MSRP: $185.95Now: $158.00Was: $185.95Qty in Cart: 0Quantity:Price:MSRP: $185.95Now: $158.00Was: $185.95Subtotal: -
On Sale
PROX Piston Kit 01.6343.A
PROX
MSRP: $139.95Now: $119.00Was: $139.95Manufactured 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,...09101163- SKU:
- 09101163
- Availability:
- Ships Same Business Day
- Weight:
- 0.67 LBS
- PISTON SIZE METRIC:
- STANDARD SIZE A
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 66.35 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- EACH
- BORE SIZE METRIC:
- 66.35 MM
MSRP: $139.95Now: $119.00Was: $139.95 -
On Sale
PROX Piston Kit 01.6324.C
PROX
MSRP: $139.95Now: $119.00Was: $139.95Manufactured 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,...09101165- SKU:
- 09101165
- Availability:
- Ships Same Business Day
- Weight:
- 0.66 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON SIZE METRIC:
- STANDARD SIZE C
- BORE SIZE METRIC:
- 66.36 MM
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- 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 01.6338.A
PROX
MSRP: $209.99Now: $178.00Was: $209.99Manufactured 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,...09101167- SKU:
- 09101167
- Availability:
- Ships Same Business Day
- Weight:
- 0.51 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
- BORE SIZE METRIC:
- 75.96 MM
- PISTON SIZE METRIC:
- STANDARD SIZE A
- RIDING STYLE:
- OFF-ROAD
- PISTON DIAMETER METRIC:
- 75.96 MM
- PRODUCT NAME:
- PISTON KIT
MSRP: $209.99Now: $178.00Was: $209.99 -
On Sale
PROX Piston Kit 01.4325.C
PROX
MSRP: $139.95Now: $119.00Was: $139.95Manufactured 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,...09100601- SKU:
- 09100601
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
- BORE SIZE METRIC:
- 66.36 MM
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- PISTON DIAMETER METRIC:
- 66.36 MM
- PISTON SIZE METRIC:
- STANDARD SIZE C
- 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 01.3122.C
PROX
MSRP: $94.95Now: $81.00Was: $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,...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
MSRP: $94.95Now: $81.00Was: $94.95Qty in Cart: 0Quantity:Price:MSRP: $94.95Now: $81.00Was: $94.95Subtotal: -
On Sale
PROX Piston Kit 01.3224.C
PROX
MSRP: $105.95Now: $90.00Was: $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,...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
MSRP: $105.95Now: $90.00Was: $105.95Qty in Cart: 0Quantity:Price:MSRP: $105.95Now: $90.00Was: $105.95Subtotal: -
On Sale
PROX Piston Kit 01.1343.A
PROX
MSRP: $185.95Now: $158.00Was: $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,...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
MSRP: $185.95Now: $158.00Was: $185.95Qty in Cart: 0Quantity:Price:MSRP: $185.95Now: $158.00Was: $185.95Subtotal: -
On Sale
PROX Piston Kit 01.1346.B
PROX
MSRP: $185.95Now: $158.00Was: $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,...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
MSRP: $185.95Now: $158.00Was: $185.95Qty in Cart: 0Quantity:Price:MSRP: $185.95Now: $158.00Was: $185.95Subtotal: -
On Sale
PROX Piston Kit 01.3341.B
PROX
MSRP: $179.95Now: $153.00Was: $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,...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
MSRP: $179.95Now: $153.00Was: $179.95 -
On Sale
PROX Piston Kit 01.4342.C
PROX
MSRP: $179.95Now: $153.00Was: $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,...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
MSRP: $179.95Now: $153.00Was: $179.95Qty in Cart: 0Quantity:Price:MSRP: $179.95Now: $153.00Was: $179.95Subtotal: -
On Sale
PROX Piston Kit 01.6226.D
PROX
MSRP: $124.95Now: $106.00Was: $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,...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
MSRP: $124.95Now: $106.00Was: $124.95Qty in Cart: 0Quantity:Price:MSRP: $124.95Now: $106.00Was: $124.95Subtotal: -
On Sale
PROX Piston Kit 01.1232.B
PROX
MSRP: $159.95Now: $136.00Was: $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,...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
MSRP: $159.95Now: $136.00Was: $159.95 -
On Sale
PROX Piston Kit 01.1413.A
PROX
MSRP: $195.95Now: $167.00Was: $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,...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
MSRP: $195.95Now: $167.00Was: $195.95Qty in Cart: 0Quantity:Price:MSRP: $195.95Now: $167.00Was: $195.95Subtotal: -
On Sale
PROX Piston Kit 01.6394.C
PROX
MSRP: $189.95Now: $161.00Was: $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,...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
MSRP: $189.95Now: $161.00Was: $189.95Qty in Cart: 0Quantity:Price:MSRP: $189.95Now: $161.00Was: $189.95Subtotal: -
On Sale
PROX Piston Kit 01.2414.C
PROX
MSRP: $179.95Now: $153.00Was: $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,...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
MSRP: $179.95Now: $153.00Was: $179.95Qty in Cart: 0Quantity:Price:MSRP: $179.95Now: $153.00Was: $179.95Subtotal: -
On Sale
PROX Piston Kit 01.6228.B
PROX
MSRP: $139.95Now: $119.00Was: $139.95Manufactured 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,...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
MSRP: $139.95Now: $119.00Was: $139.95Qty in Cart: 0Quantity:Price:MSRP: $139.95Now: $119.00Was: $139.95Subtotal: -
On Sale
PROX Piston Kit 01.6228.C
PROX
MSRP: $139.95Now: $119.00Was: $139.95Manufactured 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,...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
MSRP: $139.95Now: $119.00Was: $139.95Qty in Cart: 0Quantity:Price:MSRP: $139.95Now: $119.00Was: $139.95Subtotal: -
On Sale
PROX Piston Kit - 300EXC TPI 01.6388.B
PROX
MSRP: $189.95Now: $161.00Was: $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,...09106267- SKU:
- 09106267
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $189.95Now: $161.00Was: $189.95Qty in Cart: 0Quantity:Price:MSRP: $189.95Now: $161.00Was: $189.95Subtotal: -
On Sale
PROX Piston Kit - Standard - Yamaha PW80 01.2008.000
PROX
MSRP: $79.95Now: $68.00Was: $79.95Piston Kit for offroad applications09106098- 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
MSRP: $79.95Now: $68.00Was: $79.95Qty in Cart: 0Quantity:Price:MSRP: $79.95Now: $68.00Was: $79.95Subtotal:
