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
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WSM Top-End Rebuild Kit - Original Series - 1 mm 010-817-14
WSM
$223.48A top-end rebuild demands precision components that restore your engine to factory specifications or better. The WSM Original Series kit consolidates everything you need in one package—pistons, rings, pins, and gaskets—eliminating the risk of mixing...09030036- SKU:
- 09030036
- Availability:
- Ships Same Business Day
- Weight:
- 3.50 LBS
- PRODUCT NAME:
- REBUILD KIT
- BORE SIZE METRIC:
- 83.00 MM
- PISTON SIZE METRIC:
- +1.00 MM
- TYPE:
- TOP END
- UNITS:
- EACH
- MODEL:
- ORIGINAL SERIES
- PISTON MATERIAL:
- ALUMINUM
- RIDING STYLE:
- WATERCRAFT
$223.48Qty in Cart: 0Quantity:Price:$223.48Subtotal: -
WSM Top-End Rebuild Kit - Platinum Series - .50 mm 010-808-12P
WSM
$250.31A top-end rebuild demands precision components that can withstand extreme combustion pressures and sustained RPM loads. The WSM Platinum Series kit eliminates the guesswork by pairing OEM-quality pistons with premium racing needle bearings and a complete...09030744- SKU:
- 09030744
- Availability:
- Ships Same Business Day
- Weight:
- 3.40 LBS
- PISTON SIZE METRIC:
- +0.50 MM
- PRODUCT NAME:
- REBUILD KIT
- MODEL:
- PLATINUM SERIES
- BORE SIZE METRIC:
- 82.50 MM
- PISTON MATERIAL:
- ALUMINUM
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- TOP END
- UNITS:
- KIT
$250.31 -
WSM Top-End Rebuild Kit - Platinum Series - 1 mm 010-808-14P
WSM
$250.31A complete top-end rebuild requires precision-matched components that work in concert—mismatched or worn parts will compromise compression, increase blow-by, and kill your power output. The WSM Platinum Series kit eliminates guesswork by pairing...09030745- SKU:
- 09030745
- Availability:
- Ships Same Business Day
- Weight:
- 3.40 LBS
- MODEL:
- PLATINUM SERIES
- PISTON SIZE METRIC:
- +1.00 MM
- TYPE:
- TOP END
- UNITS:
- EACH
- PRODUCT NAME:
- REBUILD KIT
- BORE SIZE METRIC:
- 83.00 MM
- PISTON MATERIAL:
- ALUMINUM
- RIDING STYLE:
- WATERCRAFT
$250.31 -
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 premium racing needle bearings and complete gasket...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, rings, and bearing components into one complete package—no...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 package, saving you time sourcing individual parts and...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 and performance gains you need for consistent lap times...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 you're chasing lap times or tackling demanding terrain...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 OE-equivalent dependability while offering superior durability...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 friction and wear while maintaining precise combustion...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 aluminum alloy construction, keeping your engine...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: $220.95Now: $199.00Was: $220.95If 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 precision-manufactured components designed to handle the demands of...09031775- SKU:
- 09031775
- Availability:
- Ships Same Business Day
- Weight:
- 1.54 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 - 66.35 mm - KTM P4C0664083001B
ATHENA
MSRP: $178.95Now: $161.00Was: $178.95When 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 friction and improving combustion efficiency—giving you...09031779- SKU:
- 09031779
- Availability:
- Ships Same Business Day
- Weight:
- 1.39 LBS
MSRP: $178.95Now: $161.00Was: $178.95 -
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 improved sealing efficiency and reduced friction—critical...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: $115.95Now: $104.00Was: $115.95Your 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 enhanced durability through advanced metallurgy and CNC...09031782- SKU:
- 09031782
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 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 - 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 durability and performance through high-silicon...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: $145.95Now: $131.00Was: $145.95When 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 combustion efficiency, allowing you to maintain peak...09031787- SKU:
- 09031787
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
MSRP: $145.95Now: $131.00Was: $145.95Qty in Cart: 0Quantity:Price:MSRP: $145.95Now: $131.00Was: $145.95Subtotal: -
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 restoring a worn powerplant or refreshing after...09031805- SKU:
- 09031805
- Availability:
- Ships Same Business Day
- Weight:
- 14.54 LBS
$1,225.95 -
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 CNC-manufactured for exact tolerances, this kit reduces...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 bikes that demand reliable performance in demanding...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:
