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
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LA Sleeve Honda CR250R 1999-2000 Cylinder Rebuild Kit LAS-5375K
LA SLEEVE
$422.95If you're rebuilding a Honda CR250R top-end, you need a sleeve and piston kit that restores—or exceeds—original compression and ring seal. The LA Sleeve kit delivers measurable gains in torque and horsepower by pairing a centrifugally-spun Moly2000...09310413- SKU:
- 09310413
- Availability:
- Ships Same Business Day
- Weight:
- 2.80 LBS
- MATERIAL:
- CAST
- MATERIAL:
- IRON
- PRODUCT NAME:
- REBUILD KIT
- TYPE:
- CYLINDER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
$422.95 -
LA Sleeve Sleeve and Piston Kit Yamaha YZ125 1999-2000 LAS-5378K
LA SLEEVE
$360.95A worn or damaged top-end compromises compression, throttle response, and overall engine reliability on your YZ125. The LA Sleeve Sleeve and Piston Kit restores your 2-stroke's performance with a complete rebuild solution, delivering renewed horsepower,...09310419- SKU:
- 09310419
- Availability:
- Ships Same Business Day
- Weight:
- 1.90 LBS
- MATERIAL:
- CAST
- PRODUCT NAME:
- REBUILD KIT
- TYPE:
- CYLINDER
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- MATERIAL:
- IRON
$360.95 -
LA Sleeve Cylinder Sleeve Kawasaki KX125 2000 KA5429
LA SLEEVE
$131.95If you're rebuilding a KX125 engine or restoring a worn cylinder, a quality sleeve is non-negotiable—it restores bore integrity and sealing while eliminating the cost of a full cylinder replacement. The LA SLEEVE KA5429 is engineered for precision fit...KA5429- SKU:
- KA5429
- Availability:
- Ships Same Business Day
- Weight:
- 0.81 LBS
- CYLINDER BORE COATING:
- CHROME-MOLY ALLOY
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- AC
- COLOR/FINISH:
- CHROME
- PRODUCT NAME:
- CYLINDER SLEEVE
- UNITS:
- EACH
- BORE SIZE METRIC:
- 54.00 MM
$131.95 -
LA Sleeve Cylinder Sleeve Kawasaki KX125 2002 KA5473
LA SLEEVE
$131.95A worn cylinder loses compression and efficiency, directly impacting throttle response and overall engine reliability. The LA SLEEVE Cylinder Sleeve KA5473 restores your Kawasaki KX125's original performance by providing a precision-fit replacement that...KA5473- SKU:
- KA5473
- Availability:
- Ships Same Business Day
- Weight:
- 0.68 LBS
- CYLINDER BORE COATING:
- CHROME-MOLY ALLOY
- PRODUCT NAME:
- CYLINDER SLEEVE
- TYPE:
- AC
- BORE SIZE METRIC:
- 54.00 MM
- COLOR/FINISH:
- CHROME
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$131.95 -
LA Sleeve Cylinder Sleeve for 2001 Honda CR125R H5450
LA SLEEVE
$127.95Your CR125R's cylinder is the heart of engine performance—when it wears, power drops and reliability suffers. The LA SLEEVE Cylinder Sleeve H5450 restores worn cylinders to like-new condition, giving you precise piston clearance, optimal ring sealing,...H5450- SKU:
- H5450
- Availability:
- Ships Same Business Day
- Weight:
- 0.74 LBS
- COLOR/FINISH:
- CHROME
- PRODUCT NAME:
- CYLINDER SLEEVE
- UNITS:
- EACH
- BORE SIZE METRIC:
- 54.00 MM
- CYLINDER BORE COATING:
- CHROME-MOLY ALLOY
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- AC
$127.95 -
LA Sleeve Cylinder Sleeve 54mm Honda CR125R 2002 H5466
LA SLEEVE
$127.95If your CR125R is losing compression, bogging on acceleration, or showing signs of cylinder wear, a fresh sleeve restores the sealed bore surface that two-stroke performance demands. The LA SLEEVE H5466 gives you a cost-effective alternative to sourcing...H5466- SKU:
- H5466
- Availability:
- Ships Same Business Day
- Weight:
- 0.74 LBS
- BORE SIZE METRIC:
- 54.00 MM
- COLOR/FINISH:
- CHROME
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- CYLINDER SLEEVE
- UNITS:
- EACH
- CYLINDER BORE COATING:
- CHROME-MOLY ALLOY
- TYPE:
- AC
$127.95 -
KIBBLEWHITE Spring Kit 30-30015
KIBBLEWHITE
$156.91Valve spring integrity is critical to engine reliability, especially in high-RPM applications where stock springs can't handle sustained load cycles. The KIBBLEWHITE Spring Kit 30-30015 delivers precise spring rates and titanium upper collars engineered...KW3030015- SKU:
- KW3030015
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- APPLICATION:
- EXHAUST
- PRODUCT NAME:
- SPRING KIT
- SPRING OPEN PRESSURE:
- 185 LB
- TYPE:
- VALVE
- APPLICATION:
- INTAKE
- RIDING STYLE:
- OFF-ROAD
- MATERIAL:
- TITANIUM
- SPRING LIFT IMPERIAL:
- 0.400'
- UNITS:
- KIT
$156.91 -
KIBBLEWHITE Intake Valve 30-3003
KIBBLEWHITE
$37.55If you're building a high-revving engine or restoring a race-proven platform, intake valve quality directly impacts combustion efficiency, thermal management, and long-term reliability. KIBBLEWHITE's Black Diamond™ valves are engineered to withstand...KW303003- SKU:
- KW303003
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
- HEAD DIAMETER METRIC:
- 36.00 MM
- LENGTH IMPERIAL:
- 4.165'
- MODEL:
- BLACK DIAMOND™
- TULIP ANGLE:
- 23°
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- APPLICATION:
- INTAKE
- PRODUCT NAME:
- VALVE
- STEM DIAMETER IMPERIAL:
- 0.2590'
$37.55 -
KIBBLEWHITE Exhaust Valve 30-3004
KIBBLEWHITE
$37.55Valve degradation directly impacts combustion efficiency, throttle response, and engine longevity—especially under sustained high-RPM operation. The KIBBLEWHITE Black Diamond™ Exhaust Valve (30-3004) combats this with precision engineering and material...KW303004- SKU:
- KW303004
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
- MATERIAL:
- STEEL
- PRODUCT NAME:
- VALVE
- STEM DIAMETER IMPERIAL:
- 0.2585'
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- APPLICATION:
- EXHAUST
- HEAD DIAMETER METRIC:
- 31.00 MM
- LENGTH IMPERIAL:
- 4.095'
- MODEL:
- BLACK DIAMOND™
- TULIP ANGLE:
- 29°
$37.55 -
KIBBLEWHITE Spring Kit 30-30077
KIBBLEWHITE
$130.65A quality valve spring kit is fundamental to reliable engine performance, and the KIBBLEWHITE Spring Kit 30-30077 delivers the precision engineering required for consistent valve train operation across a wide range of applications. Whether you're...KW3030077- SKU:
- KW3030077
- Availability:
- Ships Same Business Day
- Weight:
- 0.38 LBS
- APPLICATION:
- INTAKE
- PRODUCT NAME:
- SPRING KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- APPLICATION:
- EXHAUST
- SPRING LIFT IMPERIAL:
- 0.355'
- SPRING OPEN PRESSURE:
- 150 LB
- TYPE:
- VALVE
- MATERIAL:
- TITANIUM
$130.65 -
KIBBLEWHITE Cast Iron Valve Seat 10-SC320
KIBBLEWHITE
$8.62Valve seat recession and microwelding failures can compromise engine reliability and performance in high-demand applications. The KIBBLEWHITE Cast Iron Valve Seat 10-SC320 uses advanced powdered metal technology to deliver exceptional hardness and...09261633- SKU:
- 09261633
- Availability:
- Ships Same Business Day
- Weight:
- 0.07 LBS
- INSIDE DIAMETER METRIC:
- 24.00 MM
- PRODUCT NAME:
- VALVE SEAT
- RIDING STYLE:
- ATV
- UNITS:
- EACH
- HEAD DIAMETER METRIC:
- 32.00 MM
- OUTSIDE DIAMETER METRIC:
- 32.00 MM
- APPLICATION:
- INTAKE
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- VALVE SEAT HEIGHT METRIC:
- 9.50 MM
$8.62 -
KIBBLEWHITE Cast Iron Valve Seat 10-SC330
KIBBLEWHITE
$8.75Valve seat recession and microwelding are silent killers in high-rpm applications—they compromise combustion sealing and accelerate wear, especially under boost or alternative fuels. The KIBBLEWHITE Cast Iron Valve Seat 10-SC330 is engineered with a...09261634- SKU:
- 09261634
- Availability:
- Ships Same Business Day
- Weight:
- 0.07 LBS
- HEAD DIAMETER METRIC:
- 33.00 MM
- INSIDE DIAMETER METRIC:
- 24.00 MM
- APPLICATION:
- EXHAUST
- OUTSIDE DIAMETER METRIC:
- 33.00 MM
- PRODUCT NAME:
- VALVE SEAT
- UNITS:
- EACH
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- VALVE SEAT HEIGHT METRIC:
- 9.50 MM
$8.75 -
KIBBLEWHITE Cast Iron Valve Seat 10-SC340
KIBBLEWHITE
$8.89Valve seat recession and microwelding are silent killers of engine durability, especially in high-rpm and forced induction applications. Kibblewhite's cast iron valve seats use advanced powdered metal technology to deliver uniform hardness and...09261635- SKU:
- 09261635
- Availability:
- Ships Same Business Day
- Weight:
- 0.06 LBS
- APPLICATION:
- EXHAUST
- UNITS:
- EACH
- OUTSIDE DIAMETER METRIC:
- 34.00 MM
- PRODUCT NAME:
- VALVE SEAT
- INSIDE DIAMETER METRIC:
- 26.00 MM
- MATERIAL:
- STEEL
- HEAD DIAMETER METRIC:
- 34.00 MM
- RIDING STYLE:
- OFF-ROAD
- VALVE SEAT HEIGHT METRIC:
- 9.50 MM
$8.89 -
KIBBLEWHITE Intake Valve 30-30221
KIBBLEWHITE
$31.01Intake valve performance directly impacts combustion efficiency, throttle response, and overall engine reliability—especially under high RPM conditions where factory valves often fall short. The KIBBLEWHITE Black Diamond™ 30-30221 delivers superior...20080221- SKU:
- 20080221
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- LENGTH IMPERIAL:
- 3.325'
- MODEL:
- BLACK DIAMOND™
- PRODUCT NAME:
- VALVE
- APPLICATION:
- INTAKE
- STEM DIAMETER IMPERIAL:
- 0.2158'
- UNITS:
- EACH
- HEAD DIAMETER METRIC:
- 37.00 MM
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- TULIP ANGLE:
- 20°
$31.01 -
KIBBLEWHITE Exhaust Valve 30-30223
KIBBLEWHITE
$31.01Exhaust valves are critical to engine reliability and performance—they're exposed to extreme heat and wear cycles that demand uncompromising durability. The KIBBLEWHITE Black Diamond™ valve delivers the precision engineering and material quality required...20080223- SKU:
- 20080223
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- HEAD DIAMETER METRIC:
- 31.00 MM
- LENGTH IMPERIAL:
- 3.310'
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- STEM DIAMETER IMPERIAL:
- 0.1957'
- TULIP ANGLE:
- 20°
- APPLICATION:
- EXHAUST
- PRODUCT NAME:
- VALVE
- UNITS:
- EACH
- MODEL:
- BLACK DIAMOND™
$31.01 -
KIBBLEWHITE Spring Kit 40-40100
KIBBLEWHITE
$220.26A valve spring kit is fundamental to any serious engine build—weak or worn springs compromise valve timing, reduce horsepower, and accelerate component wear. The KIBBLEWHITE Spring Kit 40-40100 delivers the precision engineering and durability required...09260167- SKU:
- 09260167
- Availability:
- Ships Same Business Day
- Weight:
- 0.34 LBS
- APPLICATION:
- INTAKE
- RIDING STYLE:
- OFF-ROAD
- SPRING OPEN PRESSURE:
- 155 LB
- TYPE:
- VALVE
- MATERIAL:
- TITANIUM
- PRODUCT NAME:
- SPRING KIT
- UNITS:
- KIT
- APPLICATION:
- EXHAUST
- SPRING LIFT IMPERIAL:
- 0.445'
$220.26 -
KIBBLEWHITE Intake Valve - KX/RMZ - Standard 40-40140H
KIBBLEWHITE
$37.55Intake valve performance directly impacts combustion efficiency and engine responsiveness—particularly critical on KX/RMZ platforms where precision tolerances demand uncompromising quality. KIBBLEWHITE's Black Diamond™ valves combine superior metallurgy...09260170- SKU:
- 09260170
- Availability:
- Ships Same Business Day
- Weight:
- 0.07 LBS
- MODEL:
- BLACK DIAMOND™
- STEM DIAMETER IMPERIAL:
- 0.1765'
- APPLICATION:
- INTAKE
- LENGTH IMPERIAL:
- 3.120'
- UNITS:
- EACH
- HEAD DIAMETER METRIC:
- 31.00 MM
- MATERIAL:
- STAINLESS STEEL
- PRODUCT NAME:
- VALVE
- TULIP ANGLE:
- 20°
- RIDING STYLE:
- OFF-ROAD
$37.55 -
KIBBLEWHITE Exhaust Valve - KX/RMZ - Standard 40-40143H
KIBBLEWHITE
$37.55Exhaust valves are engineered for extreme abuse—constant thermal cycling, combustion pressures, and high RPMs demand materials that won't degrade. The Kibblewhite Black Diamond™ valve gives you factory-proven durability with measurably reduced friction,...09260172- SKU:
- 09260172
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- TULIP ANGLE:
- 25°
- STEM DIAMETER IMPERIAL:
- 0.1756'
- APPLICATION:
- EXHAUST
- LENGTH IMPERIAL:
- 3.125'
- MODEL:
- BLACK DIAMOND™
- HEAD DIAMETER METRIC:
- 25.00 MM
- MATERIAL:
- STAINLESS STEEL
- PRODUCT NAME:
- VALVE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$37.55 -
KIBBLEWHITE Intake Valve 80-80214H
KIBBLEWHITE
$37.55Intake valve performance directly impacts your engine's breathing efficiency, combustion timing, and overall power output. KIBBLEWHITE's White Diamond™ valves eliminate the weak link in your cylinder head with precision engineering and superior materials...09260107- SKU:
- 09260107
- Availability:
- Ships Same Business Day
- Weight:
- 0.06 LBS
- HEAD DIAMETER METRIC:
- 28.00 MM
- MATERIAL:
- STAINLESS STEEL
- PRODUCT NAME:
- VALVE
- APPLICATION:
- INTAKE
- RIDING STYLE:
- ATV
- TULIP ANGLE:
- 15°
- UNITS:
- EACH
- MODEL:
- WHITE DIAMOND™
- RIDING STYLE:
- OFF-ROAD
- STEM DIAMETER IMPERIAL:
- 0.1765'
- LENGTH IMPERIAL:
- 3.030'
- SIZE METRIC:
- OVERSIZE
$37.55 -
KIBBLEWHITE Intake Valve 80-80215H
KIBBLEWHITE
$37.55When you're pushing peak RPMs on track, valve integrity becomes non-negotiable. KIBBLEWHITE's White Diamond™ intake valves are precision-forged from premium EV8 stainless steel or Inconel-751, then hard chrome plated to withstand extreme heat cycles and...09260108- SKU:
- 09260108
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- STEM DIAMETER IMPERIAL:
- 0.1765'
- HEAD DIAMETER METRIC:
- 27.00 MM
- MATERIAL:
- STAINLESS STEEL
- PRODUCT NAME:
- VALVE
- RIDING STYLE:
- OFF-ROAD
- SIZE METRIC:
- STANDARD
- APPLICATION:
- CENTER INTAKE
- LENGTH IMPERIAL:
- 3.000'
- RIDING STYLE:
- ATV
- UNITS:
- EACH
- MODEL:
- WHITE DIAMOND™
- TULIP ANGLE:
- 15°
$37.55
