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...09031804- SKU:
- 09031804
- Availability:
- Ships Same Business Day
- Weight:
- 14.52 LBS
$1,225.95Qty in Cart: 0Quantity:Price:$1,225.95Subtotal: -
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...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...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...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...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...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...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: $265.02 -
On Sale
ATHENA Piston Kit with Gaskets - 95.98 mm - KX450F P5F0960068007B
ATHENA
MSRP: $289.95Now: $239.00Was: $289.95A 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...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: $289.95Now: $239.00Was: $289.95 -
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...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: $269.95Now: $252.00Was: $269.95When 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...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: $269.95Now: $252.00Was: $269.95 -
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...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...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 - 87.96 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...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: $311.02Qty in Cart: 0Quantity:Price:MSRP: $311.02Now: $280.00Was: $311.02Subtotal: -
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...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: $283.95Qty in Cart: 0Quantity:Price:MSRP: $283.95Now: $256.00Was: $283.95Subtotal: -
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...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: $249.95Qty in Cart: 0Quantity:Price:MSRP: $249.95Now: $225.00Was: $249.95Subtotal: -
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...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: $289.95Now: $218.00Was: $289.95When 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...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: $289.95Now: $218.00Was: $289.95 -
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...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 -
WSM Top-End Rebuild Kit - Original Series - Standard 010-834-10
WSM
$357.62A top-end rebuild demands precision components that can withstand sustained high RPM loads without compromise. The WSM Top-End Rebuild Kit delivers OEM-quality pistons, rings, and supporting hardware...01083410- SKU:
- 01083410
- Availability:
- Ships Same Business Day
- Weight:
- 3.75 LBS
- BORE SIZE METRIC:
- 71.30 MM
- PISTON SIZE METRIC:
- STANDARD
- PISTON MATERIAL:
- ALUMINUM
- UNITS:
- EACH
- MODEL:
- ORIGINAL SERIES
- PRODUCT NAME:
- REBUILD KIT
- RIDING STYLE:
- WATERCRAFT
- TYPE:
- TOP END
$357.62Qty in Cart: 0Quantity:Price:$357.62Subtotal: -
WSM Top-End Rebuild Kit - Original Series - Standard 010-802-10
WSM
$247.87A top-end rebuild is essential maintenance for any high-performance engine, and the WSM Original Series kit delivers OEM-quality components at a fraction of full-engine rebuild costs. This...01080210- SKU:
- 01080210
- Availability:
- Ships Same Business Day
- Weight:
- 2.60 LBS
- BORE - OVERSIZE METRIC:
- STANDARD
- PRODUCT NAME:
- REBUILD KIT
- UNITS:
- EACH
- BORE SIZE METRIC:
- 77.00 MM
- MODEL:
- ORIGINAL SERIES
- TYPE:
- TOP END
- BORE - OVERSIZE:
- STANDARD
- RIDING STYLE:
- WATERCRAFT
- PISTON MATERIAL:
- ALUMINUM
$247.87
