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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Wiseco Piston Kit for Honda CR250R 2005-2007 66.40mm PK1381
WISECO
$309.95The Wiseco PK1381 is engineered for CR250R riders who need a proven top-end rebuild that restores or exceeds factory performance. If you're experiencing power loss, worn compression, or simply demand...09030550- SKU:
- 09030550
- Availability:
- Ships Same Business Day
- Weight:
- 1.44 LBS
- COOLING SYSTEM:
- LIQUID COOLED
- DISPLACEMENT:
- 249 CC
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- BORE SIZE METRIC:
- 66.40 MM
- MODEL:
- RACER'S CHOICE
- PISTON MATERIAL:
- ALUMINUM
- PISTON MATERIAL:
- FORGED
- UNITS:
- EACH
- PRODUCT NAME:
- REBUILD KIT
- STROKE LENGTH METRIC:
- 72.00 MM
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
$309.95Qty in Cart: 0Quantity:Price:$309.95Subtotal: -
Wiseco Honda CRF450R 2002-2008 Piston Kit PK1233
WISECO
$390.95When you're rebuilding a CRF450R top end, you need a piston kit that matches the precision your engine demands. The Wiseco PK1233 delivers the bore accuracy and compression ratio necessary for...09030552- SKU:
- 09030552
- Availability:
- Ships Same Business Day
- Weight:
- 1.55 LBS
- BORE SIZE METRIC:
- 96.00 MM
- MODEL:
- FORGED SERIES
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- DISPLACEMENT:
- 449 CC
- PISTON DIAMETER METRIC:
- 95.94 MM
- SKIRT COATING:
- ARMORGLIDE®
- UNITS:
- KIT
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- PRODUCT NAME:
- REBUILD KIT
- STROKE LENGTH METRIC:
- 62.10 MM
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- 2618 ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
$390.95 -
Wiseco Piston Kit 77mm 13.1:1 for 2004-2005 Kawasaki KX250F PK1237
WISECO
$308.95A complete top-end rebuild demands precision components that can handle sustained high RPMs and aggressive tuning. The Wiseco PK1237 delivers race-proven engineering in a bolt-together package,...09030555- SKU:
- 09030555
- Availability:
- Ships Same Business Day
- Weight:
- 1.10 LBS
- BORE - OVERSIZE METRIC:
- STANDARD
- PISTON MATERIAL:
- 2618 ALUMINUM ALLOY
- PRODUCT NAME:
- REBUILD KIT
- BORE - OVERSIZE:
- STANDARD
- BORE SIZE METRIC:
- 77.00 MM
- DISPLACEMENT:
- 250 CC
- ENGINE TYPE:
- 4-STROKE
- MODEL:
- FORGED SERIES
- SKIRT COATING:
- NON-COATED
- STROKE LENGTH METRIC:
- 53.60 MM
- COMPRESSION RATIO IMPERIAL:
- 13.1:1
- PISTON DIAMETER METRIC:
- 76.96 MM
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
$308.95 -
Wiseco Yamaha WR250F 2005-2013 Piston Kit PK1384
WISECO
$344.95When your WR250F's top end shows wear, you lose compression, reliability, and the crisp power delivery that keeps you competitive. The Wiseco PK1384 restores full performance with OEM-quality pistons...09030558- SKU:
- 09030558
- Availability:
- Ships Same Business Day
- Weight:
- 1.15 LBS
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- 2618 ALUMINUM ALLOY
- TYPE:
- TOP END
- PISTON DIAMETER METRIC:
- 76.95 MM
- PRODUCT NAME:
- REBUILD KIT
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- COMPRESSION RATIO IMPERIAL:
- 13.5:1
- RIDING STYLE:
- OFF-ROAD
- SKIRT COATING:
- ARMORGLIDE®
- UNITS:
- KIT
- BORE SIZE METRIC:
- 77.00 MM
- DISPLACEMENT:
- 250 CC
- MODEL:
- FORGED SERIES
- RIDING STYLE:
- STREET
- STROKE LENGTH METRIC:
- 53.60 MM
$344.95Qty in Cart: 0Quantity:Price:$344.95Subtotal: -
Wiseco YZ250F 2005-2007 WR250F 2005-2013 Piston Kit with Gaskets PK1401
WISECO
$299.95When your YZ250F or WR250F starts showing signs of wear—loss of compression, rough idle, or declining power—a top-end rebuild is often the most cost-effective way to restore full performance. The...09030559- SKU:
- 09030559
- Availability:
- Ships Same Business Day
- Weight:
- 1.25 LBS
- BORE - OVERSIZE:
- STANDARD
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- 2618 ALUMINUM ALLOY
- PRODUCT NAME:
- REBUILD KIT
- BORE - OVERSIZE METRIC:
- STANDARD
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- PISTON DIAMETER METRIC:
- 76.95 MM
- TYPE:
- TOP END
- BORE SIZE METRIC:
- 77.00 MM
- DISPLACEMENT:
- 250 CC
- MODEL:
- FORGED SERIES
- SKIRT COATING:
- NON-COATED
- STROKE LENGTH METRIC:
- 53.60 MM
$299.95Qty in Cart: 0Quantity:Price:$299.95Subtotal: -
Wiseco Piston Kit Standard 39mm 11:1 Compression Honda Z50R 1982-1987 4828M03900
WISECO
$119.95If you're running a Honda Z50R and want to maximize power output without sacrificing reliability, the Wiseco 4828M03900 piston kit delivers the compression ratio and material quality needed for...09100738- SKU:
- 09100738
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- PISTON MATERIAL:
- FORGED
- RIDING STYLE:
- STREET
- STROKE LENGTH METRIC:
- 41.40 MM
- COMPRESSION RATIO IMPERIAL:
- 11.0:1
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- PRODUCT NAME:
- PISTON
- BORE SIZE METRIC:
- 39.00 MM
- DISPLACEMENT:
- 49,50 CC
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- UNITS:
- EACH
$119.95Qty in Cart: 0Quantity:Price:$119.95Subtotal: -
Wiseco Piston Kit Sea-Doo 650 1993-1994 WK1118
WISECO
$392.70If you're running a Sea-Doo 650 and want to restore lost compression or build additional power, piston replacement is non-negotiable. The Wiseco WK1118 delivers the precision fit and material quality...WK1118- SKU:
- WK1118
- Availability:
- Ships Same Business Day
- Weight:
- 2.63 LBS
- BORE SIZE METRIC:
- 79.00 MM
- MODEL:
- FORGED SERIES
- PRODUCT NAME:
- REBUILD KIT
- BORE - OVERSIZE:
- +1,00 MM
- PISTON DIAMETER METRIC:
- 73.90 MM
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
- RIDING STYLE:
- WATERCRAFT
- BORE - OVERSIZE METRIC:
- +1.00 MM
- DISPLACEMENT:
- 666 CC
- UNITS:
- KIT
- ENGINE TYPE:
- 2-STROKE
- SKIRT COATING:
- NON-COATED
- TYPE:
- TOP END
$392.70 -
Wiseco Piston Kit Sea Doo XP Limited 1998-1999 951 040 WK1213
WISECO
$459.57If you're running a 1998-1999 Sea-Doo XP Limited 951, piston quality directly impacts how much power you can reliably extract from your engine. The Wiseco WK1213 delivers CNC-machined Pro-Lite...WK1213- SKU:
- WK1213
- Availability:
- Ships Same Business Day
- Weight:
- 3.25 LBS
- SKIRT COATING:
- NON-COATED
- TYPE:
- TOP END
- UNITS:
- KIT
- BORE - OVERSIZE METRIC:
- +1.00 MM
- DISPLACEMENT:
- 971 CC
- ENGINE TYPE:
- 2-STROKE
- MODEL:
- FORGED SERIES
- BORE - OVERSIZE:
- +1,00 MM
- BORE SIZE METRIC:
- 89.00 MM
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
- RIDING STYLE:
- WATERCRAFT
- PISTON DIAMETER METRIC:
- 88.90 MM
- PRODUCT NAME:
- REBUILD KIT
$459.57 -
Wiseco Piston Kit Yamaha GP1200 1997-1999 WK1313
WISECO
$594.95If you're running a Yamaha GP1200, piston wear directly impacts throttle response, fuel efficiency, and engine longevity. The Wiseco WK1313 restores—or exceeds—OEM performance with a complete...WK1313- SKU:
- WK1313
- Availability:
- Ships Same Business Day
- Weight:
- 4.70 LBS
- BORE SIZE METRIC:
- 84.50 MM
- MODEL:
- FORGED SERIES
- RIDING STYLE:
- WATERCRAFT
- BORE - OVERSIZE:
- +0,50 MM
- PISTON DIAMETER METRIC:
- 84.37 MM
- SKIRT COATING:
- NON-COATED
- UNITS:
- KIT
- BORE - OVERSIZE METRIC:
- +0.50 MM
- PRODUCT NAME:
- REBUILD KIT
- TYPE:
- TOP END
- DISPLACEMENT:
- 1142 CC
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
$594.95 -
On Sale
Wiseco Piston Kit Yamaha GP 1200 WaveRunner 1997-1999 1 mm WK1314
WISECO
MSRP: $581.67Now: $372.00Was: $581.67Factory pistons won't survive sustained high-RPM operation in a 2-stroke watercraft—thermal stress and detonation will cause catastrophic failure. The Wiseco WK1314 kit is engineered specifically for...WK1314- SKU:
- WK1314
- Availability:
- Ships Same Business Day
- Weight:
- 4.70 LBS
- BORE SIZE METRIC:
- 85.00 MM
- DISPLACEMENT:
- 1156 CC
- MODEL:
- FORGED SERIES
- PRODUCT NAME:
- REBUILD KIT
- BORE - OVERSIZE:
- +1,00 MM
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
- RIDING STYLE:
- WATERCRAFT
- BORE - OVERSIZE METRIC:
- +1.00 MM
- ENGINE TYPE:
- 2-STROKE
- UNITS:
- KIT
- PISTON DIAMETER METRIC:
- 84.87 MM
- SKIRT COATING:
- NON-COATED
- TYPE:
- TOP END
MSRP: $581.67Now: $372.00Was: $581.67 -
Wiseco Piston Kit Honda CRF150F 2006-2017 57.5mm 10:1 Compression 40132M05750
WISECO
$154.95If you're running a Honda CRF150F and want measurable gains in power and throttle response, a high-compression piston upgrade is one of the most direct paths to performance. The Wiseco 40132M05750...09103946- SKU:
- 09103946
- Availability:
- Ships Same Business Day
- Weight:
- 0.40 LBS
- COMPRESSION RATIO IMPERIAL:
- 10.0:1
- BORE SIZE METRIC:
- 57.50 MM
- BORE - OVERSIZE METRIC:
- STANDARD
- ENGINE TYPE:
- 4-STROKE
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- PRODUCT NAME:
- PISTON
- STROKE LENGTH METRIC:
- 57.50 MM
- UNITS:
- EACH
- BORE - OVERSIZE:
- STANDARD
- RIDING STYLE:
- OFF-ROAD
$154.95Qty in Cart: 0Quantity:Price:$154.95Subtotal: -
Wiseco Piston Kit Kawasaki KX100 1995-2021 RE907M05450
WISECO
$154.95The Wiseco RE907M05450 Racer Elite Piston Kit delivers the precision engineering your KX100 demands when you're pushing hard on the track. With a 54.50 mm bore and advanced alloy construction, this...09105094- SKU:
- 09105094
- Availability:
- Ships Same Business Day
- Weight:
- 0.45 LBS
- BORE SIZE METRIC:
- 54.50 MM
- UNITS:
- KIT
- BORE - OVERSIZE:
- +2,00 MM
- BORE - OVERSIZE METRIC:
- +2.00 MM
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- PISTON KIT
- SKIRT COATING:
- ARMORFIT™
- PISTON MATERIAL:
- 2000 SERIES ALLOY
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- RACER ELITE
- PISTON MATERIAL:
- FORGED
$154.95Qty in Cart: 0Quantity:Price:$154.95Subtotal: -
Wiseco Piston Kit Kawasaki KX125 2001-2005 58.00mm RE927M05800
WISECO
$204.95If you're running a KX125 in competitive environments, piston durability and ring sealing directly impact your lap times and engine reliability. This Wiseco Racer Elite kit delivers the precision...09105096- SKU:
- 09105096
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- BORE - OVERSIZE:
- +4,00 MM
- ENGINE TYPE:
- 2-STROKE
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- RACER ELITE
- UNITS:
- KIT
- PISTON MATERIAL:
- FORGED
- PISTON MATERIAL:
- 2000 SERIES ALLOY
- BORE - OVERSIZE METRIC:
- +4.00 MM
- BORE SIZE METRIC:
- 58.00 MM
- PRODUCT NAME:
- PISTON KIT
- SKIRT COATING:
- ARMORFIT™
$204.95Qty in Cart: 0Quantity:Price:$204.95Subtotal: -
Wiseco Piston Kit for 1997-1999 Suzuki RM125 PK1137
WISECO
$212.95If you're running a 1997-1999 Suzuki RM125 and want measurable gains in acceleration and throttle response, a quality piston kit is one of the highest-ROI upgrades you can make. The Wiseco PK1137...09030290- SKU:
- 09030290
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- MODEL:
- PRO-LITE
- RIDING STYLE:
- OFF-ROAD
- SKIRT COATING:
- NON-COATED
- STROKE LENGTH METRIC:
- 54.00 MM
- UNITS:
- KIT
- BORE SIZE METRIC:
- 54.00 MM
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- REBUILD KIT
- TYPE:
- TOP END
- DISPLACEMENT:
- 123 CC
- PISTON DIAMETER METRIC:
- 53.96 MM
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
$212.95Qty in Cart: 0Quantity:Price:$212.95Subtotal: -
Wiseco Valve Kit YZ250F 2001-2013 SVKB2402
WISECO
$445.95Worn or degraded valves compromise combustion efficiency and can lead to costly engine damage. The Wiseco Valve Kit SVKB2402 restores your YZ250F's intake and exhaust flow with precision-engineered...09263065- SKU:
- 09263065
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
- MATERIAL:
- STEEL
- PRODUCT NAME:
- VALVE KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- APPLICATION:
- EXHAUST
- APPLICATION:
- INTAKE
$445.95Qty in Cart: 0Quantity:Price:$445.95Subtotal: -
Wiseco 54mm Racer Elite Piston Kit for 1995-2003 Honda CR125R RE908M05400
WISECO
$221.95If you're running a CR125R that's seeing serious track time, piston wear is inevitable—and a worn piston kills compression, throttle response, and overall power delivery. The Wiseco RE908M05400 Racer...09105078- SKU:
- 09105078
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- PRODUCT NAME:
- PISTON KIT
- SKIRT COATING:
- ARMORFIT™
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- PISTON MATERIAL:
- FORGED
- BORE SIZE METRIC:
- 54.00 MM
- PISTON MATERIAL:
- 2000 SERIES ALLOY
- ENGINE TYPE:
- 2-STROKE
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- RACER ELITE
- UNITS:
- KIT
$221.95 -
Wiseco Valve Kit for Suzuki RM-Z250 2007-2020 SVKB3338
WISECO
$365.95Stock valve assemblies on your RM-Z250 wear down quickly under aggressive riding, causing loss of compression and compromised engine response. The Wiseco SVKB3338 Valve Kit delivers a complete...09263070- SKU:
- 09263070
- Availability:
- Ships Same Business Day
- Weight:
- 0.95 LBS
- PRODUCT NAME:
- VALVE KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- APPLICATION:
- EXHAUST
- MATERIAL:
- STEEL
- APPLICATION:
- INTAKE
$365.95 -
Wiseco Piston Standard Kawasaki KX 250 1992-2001 617M06640
WISECO
$221.95If you're running a KX250 hard enough to wear out the original piston, you need a replacement that matches your commitment to performance. The Wiseco 617M06640 delivers the precision bore diameter...617M06640- SKU:
- 617M06640
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
- DISPLACEMENT:
- 249 CC
- STROKE LENGTH:
- 70,00 MM
- BORE SIZE METRIC:
- 66.40 MM
- PISTON MATERIAL:
- ALUMINUM ALLOY
- PISTON MATERIAL:
- FORGED
- PRODUCT NAME:
- PISTON
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- RIDING STYLE:
- OFF-ROAD
- STROKE LENGTH METRIC:
- 70.00 MM
- UNITS:
- EACH
$221.95 -
Wiseco Top End Bearing for Kawasaki KX250 1978-2007 B1022
WISECO
$25.95The Wiseco B1022 top end bearing is engineered to withstand the extreme RPM demands of high-performance KX250 engines, delivering the reliability needed when you're pushing your bike to its limits. A...B1022X- SKU:
- B1022X
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
- LENGTH METRIC:
- 23.5 MM
- MATERIAL:
- ALUMINUM
- OUTSIDE DIAMETER METRIC:
- 22 MM
- RIDING STYLE:
- ADVENTURE TOURING / DUAL-SPORT
- RIDING STYLE:
- STREET
- TYPE:
- TOP END
- APPLICATION:
- PISTON
- INSIDE DIAMETER METRIC:
- 18 MM
- MATERIAL:
- SILICONE
- PRODUCT NAME:
- BEARING
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- RIDING STYLE:
- WATERCRAFT
$25.95 -
WORKS CONNECTION Engine Timing Plug - Blue - Kawasaki 24-543
WORKS CONNECTION
$46.95Engine timing plugs might seem like a minor detail, but they're one of the first things visible when you open the clutch cover—and they set the tone for your entire build's attention to detail. WORKS...09500196- SKU:
- 09500196
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- PRODUCT NAME:
- PLUG
- RIDING STYLE:
- STREET
- TYPE:
- ENGINE
- UNITS:
- SET
- COLOR/FINISH:
- ANODIZED
- COLOR/FINISH:
- BLUE
- MATERIAL:
- 6061 T-6 ALUMINUM
- RIDING STYLE:
- OFF-ROAD
$46.95
