Dirt Bike Engine Rebuild Kits
Dirt Bike Engine Rebuild Kits for Kawasaki KX100, KTM XC-W 250 & Honda CRF250R at JJ Motorsports
Revive your dirt bike's engine to factory-fresh performance with premium rebuild kits from JJ Motorsports, featuring forged pistons, crankshafts, bearings, seals, and gaskets for superior compression, reduced vibration, and long-term reliability in motocross, enduro, and trail riding. Our selection includes complete top- and bottom-end kits designed for precise fitment, optimal oil flow, and enhanced power delivery without custom machining. Compatible with popular models like Kawasaki KX100, KTM XC/XC-W 250, Husqvarna TE250, and Honda CRF250R, these high-quality components from trusted brands ensure leak-free assembly, better heat management, and race-ready durability in dusty, high-RPM conditions. From Wiseco's comprehensive KX100 kits with hour meters to Vertex's all-in-one KTM rebuilds and Athena's high-performance CRF pistons, get everything needed for a pro-level refresh—pistons, rings, bearings, and gaskets—to restore throttle snap, efficiency, and confidence on every rip.
Shop brands like Wiseco, Vertex, and Athena for race-proven quality. Explore related categories such as dirt bike piston and ring kits for top-end focus or dirt bike engine for cylinders and valves.
Top Dirt Bike Engine Rebuild Kits
- Wiseco Engine Rebuild Kit 52.50 mm Kawasaki KX100 1995-2013 PWR173-100 – Comprehensive top- and bottom-end kit with high-quality crankshaft, rod assembly, main bearings, seals, gaskets, and hour meter bracket for Kawasaki KX100 models; ensures optimal performance and easy maintenance.
- VERTEX Engine Rebuild Kit - KTM XC/XC-W 250 | Husqvarna TE250 WR101-091 – All-in-one rebuild kit with Vertex piston, Hot Rods crankshaft, bearings/seals, transmission kit, and complete gaskets; perfect for professional top- and bottom-end refresh on KTM and Husqvarna 250cc models.
- ATHENA Piston Kit with Gaskets - 76.76 mm - CRF250R P5F0768245003B – High-performance 76.76 mm forged aluminum piston kit with rings, gaskets, and coatings for reduced friction; engineered for Honda CRF250R 4-stroke off-road with superior airflow and longevity.
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
-
WSM Top-End Rebuild Kit - Platinum Series - Standard 010-809-10P
WSM
$339.74A top-end rebuild demands precision components that can withstand extreme combustion pressures and sustained high RPM operation. The WSM Platinum Series kit delivers OEM-quality pistons paired with...09030746- SKU:
- 09030746
- Availability:
- Ships Same Business Day
- Weight:
- 4.00 LBS
- PRODUCT NAME:
- REBUILD KIT
- MODEL:
- PLATINUM SERIES
- PISTON SIZE METRIC:
- STANDARD
- TYPE:
- TOP END
- UNITS:
- EACH
- BORE SIZE METRIC:
- 87.91 MM
- PISTON MATERIAL:
- ALUMINUM
- RIDING STYLE:
- WATERCRAFT
$339.74 -
WSM Top-End Rebuild Kit - Platinum Series - .50 mm 010-809-12P
WSM
$339.74A top-end rebuild is the most direct path to restoring cylinder head performance and extending engine life. The WSM Platinum Series kit eliminates the guesswork by bundling OEM-quality pistons,...09030747- SKU:
- 09030747
- Availability:
- Ships Same Business Day
- Weight:
- 4.10 LBS
- MODEL:
- PLATINUM SERIES
- TYPE:
- TOP END
- PRODUCT NAME:
- REBUILD KIT
- UNITS:
- EACH
- BORE SIZE METRIC:
- 88.41 MM
- PISTON SIZE METRIC:
- +0.50 MM
- PISTON MATERIAL:
- ALUMINUM
- RIDING STYLE:
- WATERCRAFT
$339.74 -
On Sale
Wiseco Engine Rebuild Kit 66.40mm Bore Yamaha YZ250 2003-2020 PWR134-100
WISECO
MSRP: $710.95Now: $557.00Was: $710.95A worn or damaged YZ250 engine demands a complete rebuild to restore competitive performance and reliability. This Wiseco kit eliminates the guesswork by bundling OEM-specification components in one...09031519- SKU:
- 09031519
- Availability:
- Ships Same Business Day
- Weight:
- 13.30 LBS
MSRP: $710.95Now: $557.00Was: $710.95Qty in Cart: 0Quantity:Price:MSRP: $710.95Now: $557.00Was: $710.95Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 76.76 mm - CRF250R P5F0768245002B
ATHENA
MSRP: $203.95Now: $184.00Was: $203.95Stock pistons wear down and lose compression over time, robbing your CRF250R of throttle response and top-end power. This Athena piston kit restores OEM reliability while delivering the durability...09031703- SKU:
- 09031703
- Availability:
- Ships Same Business Day
- Weight:
- 1.08 LBS
MSRP: $203.95Now: $184.00Was: $203.95Qty in Cart: 0Quantity:Price:MSRP: $203.95Now: $184.00Was: $203.95Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 76.96 mm - WR/YZ250F P5F0770039007A
ATHENA
MSRP: $222.95Now: $201.00Was: $222.95If you're pushing your WR/YZ250F to its limits, your stock piston won't cut it. This ATHENA piston kit delivers the precision engineering and durability needed for aggressive off-road riding, whether...09031706- SKU:
- 09031706
- Availability:
- Ships Same Business Day
- Weight:
- 1.17 LBS
MSRP: $222.95Now: $201.00Was: $222.95Qty in Cart: 0Quantity:Price:MSRP: $222.95Now: $201.00Was: $222.95Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 77.96 mm - EC250F | FE250 | 250EXCF P5F0780093001B
ATHENA
MSRP: $217.95Now: $196.00Was: $217.95When your 4-stroke off-road engine is pushed to its limits, a worn or substandard piston compromises compression, throttle response, and overall reliability. The ATHENA Piston Kit delivers...09031727- SKU:
- 09031727
- Availability:
- Ships Same Business Day
- Weight:
- 1.15 LBS
MSRP: $217.95Now: $196.00Was: $217.95Qty in Cart: 0Quantity:Price:MSRP: $217.95Now: $196.00Was: $217.95Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 78.95 mm - CRF250R/RX P5F0790319001A
ATHENA
MSRP: $212.95Now: $192.00Was: $212.95The ATHENA Piston Kit delivers OEM-level reliability with measurably superior durability and performance for your CRF250R/RX. CNC-machined from high-silicon aluminum alloy, this piston reduces...09031728- SKU:
- 09031728
- Availability:
- Ships Same Business Day
- Weight:
- 1.21 LBS
MSRP: $212.95Now: $192.00Was: $212.95Qty in Cart: 0Quantity:Price:MSRP: $212.95Now: $192.00Was: $212.95Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 71.93 mm - KTM P4C0720083002A
ATHENA
MSRP: $220.95Now: $199.00Was: $220.95When you're pushing your KTM 2-stroke off-road machine to its limits, piston failure isn't an option. The ATHENA Piston Kit delivers OE-level reliability with superior durability through high-silicon...09031774- SKU:
- 09031774
- Availability:
- Ships Same Business Day
- Weight:
- 1.57 LBS
MSRP: $220.95Now: $199.00Was: $220.95Qty in Cart: 0Quantity:Price:MSRP: $220.95Now: $199.00Was: $220.95Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 71.94 mm - KTM P4C0720083002B
ATHENA
MSRP: $231.95Now: $199.00Was: $231.95If you're running a 2-stroke KTM off-road machine, piston wear directly impacts your power delivery and engine reliability. The ATHENA Piston Kit restores—or exceeds—OE performance with...09031775- SKU:
- 09031775
- Availability:
- Ships Same Business Day
- Weight:
- 1.54 LBS
MSRP: $231.95Now: $199.00Was: $231.95 -
On Sale
ATHENA Piston Kit with Gaskets - 66.35 mm - KTM P4C0664083001B
ATHENA
MSRP: $187.95Now: $161.00Was: $187.95When you're pushing your KTM 2-stroke to its limits, piston reliability directly impacts your performance and race consistency. The ATHENA Piston Kit delivers OE-equivalent durability while reducing...09031779- SKU:
- 09031779
- Availability:
- Ships Same Business Day
- Weight:
- 1.39 LBS
MSRP: $187.95Now: $161.00Was: $187.95 -
On Sale
ATHENA Piston Kit with Gaskets - 66.35 mm - KTM P4C0664045001B
ATHENA
MSRP: $178.95Now: $161.00Was: $178.95If you're running a 2-stroke off-road bike, piston wear directly impacts throttle response, compression, and overall reliability. The ATHENA Piston Kit delivers OE-level durability with measurably...09031781- SKU:
- 09031781
- Availability:
- Ships Same Business Day
- Weight:
- 1.42 LBS
MSRP: $178.95Now: $161.00Was: $178.95Qty in Cart: 0Quantity:Price:MSRP: $178.95Now: $161.00Was: $178.95Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 44.45 mm - Kawasaki P4C0445008001A
ATHENA
MSRP: $121.95Now: $104.00Was: $121.95Your 2-stroke off-road engine demands precision components that can handle extreme combustion pressures and rapid thermal cycling. The ATHENA Piston Kit delivers OE-equivalent reliability with...09031782- SKU:
- 09031782
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
MSRP: $121.95Now: $104.00Was: $121.95 -
On Sale
ATHENA Piston Kit with Gaskets - 44.46 mm - Kawasaki P4C0445008001B
ATHENA
MSRP: $115.95Now: $104.00Was: $115.95If you're running a 2-stroke off-road machine, piston wear directly impacts compression, power delivery, and engine longevity. The ATHENA Piston Kit delivers OE-equivalent reliability while improving...09031783- SKU:
- 09031783
- Availability:
- Ships Same Business Day
- Weight:
- 0.77 LBS
MSRP: $115.95Now: $104.00Was: $115.95Qty in Cart: 0Quantity:Price:MSRP: $115.95Now: $104.00Was: $115.95Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 53.96 mm - Yamaha P4C0540118014B
ATHENA
MSRP: $153.95Now: $131.00Was: $153.95When you're pushing a 2-stroke off-road engine to its limits, piston reliability becomes non-negotiable. The ATHENA Piston Kit delivers OE-level dependability with measurably improved durability and...09031787- SKU:
- 09031787
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
MSRP: $153.95Now: $131.00Was: $153.95 -
VERTEX Engine Rebuild Kit - Husqvarna | KTM WR00071
VERTEX
$1,225.95A complete engine rebuild demands precision components working in harmony—this kit eliminates guesswork by bundling all critical internal parts into one professionally-curated package. Whether you're...09031805- SKU:
- 09031805
- Availability:
- Ships Same Business Day
- Weight:
- 14.54 LBS
$1,225.95Qty in Cart: 0Quantity:Price:$1,225.95Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 95.98 mm - KX450F P5F0960072007B
ATHENA
MSRP: $263.07Now: $237.00Was: $263.07The ATHENA Piston Kit delivers the reliability you expect from OEM-quality engineering while pushing performance beyond stock limitations. Precision-engineered with high-silicon aluminum alloy and...09031751- SKU:
- 09031751
- Availability:
- Ships Same Business Day
- Weight:
- 1.53 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- TYPE:
- TOP END
- DISPLACEMENT:
- 450 CC
- MODEL:
- B
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 95.98 MM
- PISTON MATERIAL:
- FORGED
- UNITS:
- KIT
MSRP: $263.07Now: $237.00Was: $263.07Qty in Cart: 0Quantity:Price:MSRP: $263.07Now: $237.00Was: $263.07Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 87.95 mm - SXF350 P5F0880090001A
ATHENA
MSRP: $257.02Now: $231.00Was: $257.02Factory piston kits wear out and lose efficiency—upgrade to the ATHENA 87.95 mm to restore top-end power and extend engine life. This precision-engineered piston kit is built for 4-stroke off-road...09031760- SKU:
- 09031760
- Availability:
- Ships Same Business Day
- Weight:
- 1.36 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- BORE SIZE METRIC:
- 87.95 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- COMPRESSION RATIO IMPERIAL:
- 14.2:1
- DISPLACEMENT:
- 349 CC
- TYPE:
- TOP END
- MODEL:
- A
- PRODUCT NAME:
- PISTON KIT
MSRP: $257.02Now: $231.00Was: $257.02Qty in Cart: 0Quantity:Price:MSRP: $257.02Now: $231.00Was: $257.02Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 96.96 mm - YZ450F P5F0970197004B
ATHENA
MSRP: $229.95Now: $207.00Was: $229.95When your YZ450F's piston reaches the end of its service life, settling for a standard replacement means accepting compromised ring sealing and unnecessary friction losses. The ATHENA Piston Kit...09031769- SKU:
- 09031769
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- TOP END
- UNITS:
- KIT
- DISPLACEMENT:
- 450 CC
- MODEL:
- B
- RIDING STYLE:
- OFF-ROAD
- BORE SIZE METRIC:
- 96.96 MM
- COMPRESSION RATIO IMPERIAL:
- 12.8:1
- PISTON MATERIAL:
- FORGED
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
MSRP: $229.95Now: $207.00Was: $229.95Qty in Cart: 0Quantity:Price:MSRP: $229.95Now: $207.00Was: $229.95Subtotal: -
WSM Top-End Rebuild Kit - Original Series - .50 mm 010-810-12
WSM
$240.24A top-end rebuild demands precision components that restore your engine to factory specifications—or exceed them. The WSM Top-End Rebuild Kit supplies every critical component needed for a complete...01081012- SKU:
- 01081012
- Availability:
- Ships Same Business Day
- Weight:
- 2.50 LBS
- BORE - OVERSIZE:
- +0,50 MM
- BORE SIZE METRIC:
- 76.50 MM
- MODEL:
- ORIGINAL SERIES
- PISTON MATERIAL:
- ALUMINUM
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- TOP END
- UNITS:
- EACH
- BORE - OVERSIZE METRIC:
- +0.50 MM
- PRODUCT NAME:
- REBUILD KIT
$240.24Qty in Cart: 0Quantity:Price:$240.24Subtotal: -
WSM Top-End Rebuild Kit - Original Series - .50 mm 010-812-12
WSM
$195.81A top-end rebuild demands precision components that restore your engine to OEM specifications or beyond. The WSM Original Series kit delivers complete piston assembly hardware in one package,...01081212- SKU:
- 01081212
- Availability:
- Ships Same Business Day
- Weight:
- 2.25 LBS
- PRODUCT NAME:
- REBUILD KIT
- BORE - OVERSIZE:
- +0,50 MM
- BORE - OVERSIZE METRIC:
- +0.50 MM
- BORE SIZE METRIC:
- 75.50 MM
- MODEL:
- ORIGINAL SERIES
- PISTON MATERIAL:
- ALUMINUM
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- TOP END
- UNITS:
- EACH
$195.81Qty in Cart: 0Quantity:Price:$195.81Subtotal:
