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
-
VERTEX Engine Rebuild Kit - KTM WR00069
VERTEX
$1,225.95A complete engine rebuild demands precision and reliability—cutting corners on component quality will compromise performance and longevity. The VERTEX Engine Rebuild Kit for KTM consolidates nearly every critical internal component into one carefully...09031804- SKU:
- 09031804
- Availability:
- Ships Same Business Day
- Weight:
- 14.52 LBS
$1,225.95 -
On Sale
ATHENA Piston Kit with Gaskets - 95.97 mm - KX450F P5F0960072007A
ATHENA
MSRP: $263.07Now: $237.00Was: $263.07Stock pistons wear, lose compression, and rob you of the responsiveness your KX450F demands on technical terrain. This ATHENA piston kit restores full performance potential while engineering in durability for repeat heat cycles—ideal if you're running...09031750- SKU:
- 09031750
- Availability:
- Ships Same Business Day
- Weight:
- 1.55 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE SIZE METRIC:
- 95.97 MM
- DISPLACEMENT:
- 450 CC
- TYPE:
- TOP END
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- MODEL:
- A
- PRODUCT NAME:
- PISTON 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 - 95.95 mm - CRF450R P5F0960322006A
ATHENA
MSRP: $259.07Now: $233.00Was: $259.07A worn or stock piston limits your CRF450R's combustion efficiency and reliability—especially under sustained high-RPM riding or aggressive trail conditions. The ATHENA Piston Kit delivers precision-engineered performance with CNC-machined construction...09031744- SKU:
- 09031744
- Availability:
- Ships Same Business Day
- Weight:
- 1.53 LBS
- BORE SIZE METRIC:
- 95.95 MM
- DISPLACEMENT:
- 450 CC
- PRODUCT NAME:
- PISTON KIT
- COMPRESSION RATIO IMPERIAL:
- 13.5:1
- PISTON MATERIAL:
- FORGED
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- MODEL:
- A
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
MSRP: $259.07Now: $233.00Was: $259.07 -
On Sale
ATHENA Piston Kit with Gaskets - 95.96 mm - CRF450R P5F0960322006B
ATHENA
MSRP: $259.07Now: $233.00Was: $259.07A worn or damaged piston directly compromises your CRF450R's compression, power delivery, and engine longevity. The ATHENA Piston Kit delivers OE-equivalent reliability with superior wear resistance and thermal performance, ensuring consistent high-RPM...09031745- SKU:
- 09031745
- Availability:
- Ships Same Business Day
- Weight:
- 1.55 LBS
- BORE SIZE METRIC:
- 95.96 MM
- COMPRESSION RATIO IMPERIAL:
- 13.5:1
- MODEL:
- B
- PRODUCT NAME:
- PISTON KIT
- DISPLACEMENT:
- 450 CC
- TYPE:
- TOP END
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
MSRP: $259.07Now: $233.00Was: $259.07Qty in Cart: 0Quantity:Price:MSRP: $259.07Now: $233.00Was: $259.07Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 95.95 mm - CRF450R P5F0960320006A
ATHENA
MSRP: $261.07Now: $235.00Was: $261.07When your CRF450R's piston shows wear, combustion efficiency drops and power delivery suffers—this ATHENA piston kit restores that performance with precision-engineered components built to OEM specifications. The high-performance aluminum alloy...09031746- SKU:
- 09031746
- Availability:
- Ships Same Business Day
- Weight:
- 1.53 LBS
- BORE SIZE METRIC:
- 95.95 MM
- PRODUCT NAME:
- PISTON KIT
- COMPRESSION RATIO IMPERIAL:
- 13.5:1
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- MODEL:
- A
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- DISPLACEMENT:
- 450 CC
- TYPE:
- TOP END
MSRP: $261.07Now: $235.00Was: $261.07 -
On Sale
ATHENA Piston Kit with Gaskets - 95.96 mm - CRF450R P5F0960320006B
ATHENA
MSRP: $261.07Now: $235.00Was: $261.07A worn or damaged piston directly compromises combustion efficiency, power output, and engine longevity—especially in high-demand off-road riding. The ATHENA 95.96 mm Piston Kit restores your CRF450R to factory specifications with OEM-quality materials...09031747- SKU:
- 09031747
- Availability:
- Ships Same Business Day
- Weight:
- 1.50 LBS
- COMPRESSION RATIO IMPERIAL:
- 13.5:1
- PISTON MATERIAL:
- FORGED
- BORE SIZE METRIC:
- 95.96 MM
- DISPLACEMENT:
- 450 CC
- MODEL:
- B
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
MSRP: $261.07Now: $235.00Was: $261.07 -
On Sale
ATHENA Piston Kit with Gaskets - 95.97 mm - KX450F P5F0960068007A
ATHENA
MSRP: $265.02Now: $239.00Was: $265.02When you're pushing a KX450F to its limits, a worn or stock piston becomes your bottleneck—restricting flow, sapping power, and threatening reliability under sustained load. The ATHENA Piston Kit delivers a precision-engineered replacement that restores...09031752- SKU:
- 09031752
- Availability:
- Ships Same Business Day
- Weight:
- 1.50 LBS
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- ENGINE TYPE:
- 4-STROKE
- MODEL:
- A
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- DISPLACEMENT:
- 450 CC
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 95.97 MM
- TYPE:
- TOP END
MSRP: $265.02Now: $239.00Was: $265.02Qty in Cart: 0Quantity:Price:MSRP: $265.02Now: $239.00Was: $265.02Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 95.98 mm - KX450F P5F0960068007B
ATHENA
MSRP: $265.02Now: $239.00Was: $265.02A worn or damaged piston directly kills your engine's compression, throttle response, and overall reliability—especially critical in high-demand 4-stroke off-road applications. The ATHENA Piston Kit delivers precision-engineered internals that restore...09031753- SKU:
- 09031753
- Availability:
- Ships Same Business Day
- Weight:
- 1.51 LBS
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- DISPLACEMENT:
- 450 CC
- TYPE:
- TOP END
- MODEL:
- B
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 95.98 MM
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
MSRP: $265.02Now: $239.00Was: $265.02 -
On Sale
ATHENA Piston Kit with Gaskets - 95.95 mm - KX450F P5F0960066002A
ATHENA
MSRP: $273.07Now: $246.00Was: $273.07When your KX450F is pushing peak RPMs on the track or trail, a worn piston compromises compression, power delivery, and engine longevity. The ATHENA Piston Kit delivers OE-equivalent reliability with enhanced durability—engineered for riders who demand...09031754- SKU:
- 09031754
- Availability:
- Ships Same Business Day
- Weight:
- 1.60 LBS
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- MODEL:
- A
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- BORE SIZE METRIC:
- 95.95 MM
- PRODUCT NAME:
- PISTON KIT
- DISPLACEMENT:
- 450 CC
- TYPE:
- TOP END
MSRP: $273.07Now: $246.00Was: $273.07 -
On Sale
ATHENA Piston Kit with Gaskets - 94.95 mm - SXF450 P5F0950081002A
ATHENA
MSRP: $279.95Now: $252.00Was: $279.95When you're pushing your SXF450 to its limits, your piston needs to deliver reliability under extreme heat and pressure. The ATHENA Piston Kit combines OE-equivalent durability with enhanced material strength, giving you the performance gains you're...09031756- SKU:
- 09031756
- Availability:
- Ships Same Business Day
- Weight:
- 1.54 LBS
- BORE SIZE METRIC:
- 94.95 MM
- TYPE:
- TOP END
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- MODEL:
- A
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
- COMPRESSION RATIO IMPERIAL:
- 12.8:1
- PISTON MATERIAL:
- FORGED
- DISPLACEMENT:
- 449 CC
- RIDING STYLE:
- OFF-ROAD
MSRP: $279.95Now: $252.00Was: $279.95 -
On Sale
ATHENA Piston Kit with Gaskets - 94.95 mm - SXF450 P5F0950081001A
ATHENA
MSRP: $265.95Now: $239.00Was: $265.95When your 4-stroke off-road machine demands peak combustion efficiency and ring seal integrity, OE pistons become the limiting factor. The ATHENA Piston Kit delivers the durability of stock components while introducing superior material...09031758- SKU:
- 09031758
- Availability:
- Ships Same Business Day
- Weight:
- 1.55 LBS
- DISPLACEMENT:
- 450 CC
- TYPE:
- TOP END
- BORE SIZE METRIC:
- 94.95 MM
- MODEL:
- A
- PRODUCT NAME:
- PISTON KIT
- COMPRESSION RATIO IMPERIAL:
- 12.6:1
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $265.95Now: $239.00Was: $265.95Qty in Cart: 0Quantity:Price:MSRP: $265.95Now: $239.00Was: $265.95Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 94.96 mm - SXF450 P5F0950081001B
ATHENA
MSRP: $279.95Now: $252.00Was: $279.95If you're rebuilding a top-end on your 4-stroke off-road machine, piston selection directly impacts reliability under load and throttle response across the RPM band. The ATHENA Piston Kit delivers the precision engineering and material science needed to...09031759- SKU:
- 09031759
- Availability:
- Ships Same Business Day
- Weight:
- 1.54 LBS
- BORE SIZE METRIC:
- 94.96 MM
- DISPLACEMENT:
- 450 CC
- MODEL:
- B
- PRODUCT NAME:
- PISTON KIT
- PISTON MATERIAL:
- FORGED
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- COMPRESSION RATIO IMPERIAL:
- 12.6:1
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- TYPE:
- TOP END
MSRP: $279.95Now: $252.00Was: $279.95Qty in Cart: 0Quantity:Price:MSRP: $279.95Now: $252.00Was: $279.95Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 87.96 mm - SXF350 P5F0880090001B
ATHENA
MSRP: $257.02Now: $231.00Was: $257.02If you're running a KTM SXF350 at the edge of its limits, piston wear directly impacts combustion efficiency, power delivery, and engine longevity. The ATHENA Piston Kit delivers OE-equivalent reliability with measurably superior durability—critical when...09031761- SKU:
- 09031761
- Availability:
- Ships Same Business Day
- Weight:
- 1.38 LBS
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- PISTON KIT
- BORE SIZE METRIC:
- 87.96 MM
- COMPRESSION RATIO IMPERIAL:
- 14.2:1
- DISPLACEMENT:
- 349 CC
- TYPE:
- TOP END
- MODEL:
- B
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- 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 - 87.95 mm - SXF350 P5F0880079001A
ATHENA
MSRP: $295.95Now: $266.00Was: $295.95The ATHENA Piston Kit delivers the reliability of OEM components with measurably better durability and performance for your SXF350. CNC-machined from high-silicon aluminum alloy, this kit resists wear and maintains consistent combustion dynamics under...09031762- SKU:
- 09031762
- Availability:
- Ships Same Business Day
- Weight:
- 1.39 LBS
- PISTON MATERIAL:
- FORGED
- RIDING STYLE:
- STREET
- BORE SIZE METRIC:
- 87.95 MM
- RIDING STYLE:
- OFF-ROAD
- COMPRESSION RATIO IMPERIAL:
- 14.2:1
- TYPE:
- TOP END
- UNITS:
- KIT
- DISPLACEMENT:
- 349 CC
- ENGINE TYPE:
- 4-STROKE
- MODEL:
- A
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PRODUCT NAME:
- PISTON KIT
MSRP: $295.95Now: $266.00Was: $295.95Qty in Cart: 0Quantity:Price:MSRP: $295.95Now: $266.00Was: $295.95Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 87.96 mm - SXF350 P5F0880079001B
ATHENA
MSRP: $311.02Now: $280.00Was: $311.02A worn or damaged piston directly compromises combustion efficiency, throttle response, and engine longevity—particularly critical in 4-stroke off-road applications where reliability matters. The ATHENA Piston Kit delivers precision-engineered...09031763- SKU:
- 09031763
- Availability:
- Ships Same Business Day
- Weight:
- 1.39 LBS
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- STREET
- COMPRESSION RATIO IMPERIAL:
- 14.2:1
- DISPLACEMENT:
- 349 CC
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- BORE SIZE METRIC:
- 87.96 MM
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
- MODEL:
- B
MSRP: $311.02Now: $280.00Was: $311.02 -
On Sale
ATHENA Piston Kit with Gaskets - 95.96 mm - RMZ450 P5F0960061004B
ATHENA
MSRP: $283.95Now: $256.00Was: $283.95Whether you're rebuilding after a season of hard racing or upgrading to restore lost compression, the ATHENA Piston Kit delivers the reliability you need without compromise. This Japanese-engineered piston maintains OE fitment while offering superior...09031765- SKU:
- 09031765
- Availability:
- Ships Same Business Day
- Weight:
- 1.50 LBS
- BORE SIZE METRIC:
- 95.96 MM
- DISPLACEMENT:
- 450 CC
- MODEL:
- B
- PRODUCT NAME:
- PISTON KIT
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- TYPE:
- TOP END
MSRP: $283.95Now: $256.00Was: $283.95 -
On Sale
ATHENA Piston Kit with Gaskets - 96.95 mm - YZ450F P5F0970213005A
ATHENA
MSRP: $249.95Now: $225.00Was: $249.95OEM reliability meets measurable performance gains. The ATHENA Piston Kit delivers the durability you need for sustained high-RPM operation while reducing friction losses that cost you power. If you're serious about YZ450F performance, this is the...09031766- SKU:
- 09031766
- Availability:
- Ships Same Business Day
- Weight:
- 1.54 LBS
- BORE SIZE METRIC:
- 96.95 MM
- PRODUCT NAME:
- PISTON KIT
- COMPRESSION RATIO IMPERIAL:
- 13.7:1
- TYPE:
- TOP END
- ENGINE TYPE:
- 4-STROKE
- MODEL:
- A
- PISTON MATERIAL:
- ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- DISPLACEMENT:
- 449 CC
- PISTON MATERIAL:
- FORGED
- UNITS:
- KIT
MSRP: $249.95Now: $225.00Was: $249.95 -
On Sale
ATHENA Piston Kit with Gaskets - 96.96 mm - YZ450F P5F0970213005B
ATHENA
MSRP: $249.95Now: $225.00Was: $249.95Factory pistons wear out—especially under aggressive riding conditions—and a worn piston compromises compression, power delivery, and fuel efficiency. The ATHENA Piston Kit gives your YZ450F a complete refresh with OEM-quality construction and precision...09031767- SKU:
- 09031767
- Availability:
- Ships Same Business Day
- Weight:
- 1.51 LBS
- COMPRESSION RATIO IMPERIAL:
- 13.7:1
- MODEL:
- B
- DISPLACEMENT:
- 449 CC
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- BORE SIZE METRIC:
- 96.96 MM
- PRODUCT NAME:
- PISTON KIT
- TYPE:
- TOP END
MSRP: $249.95Now: $225.00Was: $249.95Qty in Cart: 0Quantity:Price:MSRP: $249.95Now: $225.00Was: $249.95Subtotal: -
On Sale
ATHENA Piston Kit with Gaskets - 96.95 mm - YZ450F P5F0970197004A
ATHENA
MSRP: $242.15Now: $218.00Was: $242.15When your YZ450F's piston is nearing the end of its service life, installing OEM-equivalent replacement parts is critical to maintaining reliability and power delivery. This ATHENA piston kit delivers the durability and performance characteristics of...09031768- SKU:
- 09031768
- Availability:
- Ships Same Business Day
- Weight:
- 1.55 LBS
- TYPE:
- TOP END
- BORE SIZE METRIC:
- 96.95 MM
- ENGINE TYPE:
- 4-STROKE
- MODEL:
- A
- PRODUCT NAME:
- PISTON KIT
- COMPRESSION RATIO IMPERIAL:
- 12.8:1
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- DISPLACEMENT:
- 450 CC
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $242.15Now: $218.00Was: $242.15 -
WSM Top-End Rebuild Kit - Original Series - .50 mm 010-834-12
WSM
$357.62A complete top-end rebuild demands precision components that restore your engine to OEM specifications without compromise. The WSM Original Series kit delivers factory-quality pistons, rings, and bearings in one package—eliminating the guesswork of...01083412- SKU:
- 01083412
- Availability:
- Ships Same Business Day
- Weight:
- 4.00 LBS
- PISTON SIZE METRIC:
- +0.50 MM
- UNITS:
- EACH
- BORE SIZE METRIC:
- 71.80 MM
- MODEL:
- ORIGINAL SERIES
- PISTON MATERIAL:
- ALUMINUM
- RIDING STYLE:
- WATERCRAFT
- PRODUCT NAME:
- REBUILD KIT
- TYPE:
- TOP END
$357.62
