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!
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- Price
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On Sale
ATHENA Piston Kit with Gaskets - 78.95 mm - CRF250R P5F0790319002A
ATHENA
MSRP: $212.95Now: $192.00Was: $212.95A worn or damaged piston directly kills your CRF250R's combustion efficiency, power output, and engine longevity. This ATHENA piston kit restores your bike to factory performance specs with precision-engineered components that handle the demands of...09031730- SKU:
- 09031730
- Availability:
- Ships Same Business Day
- Weight:
- 1.25 LBS
MSRP: $212.95Now: $192.00Was: $212.95 -
MOOSE RACING Water Pump Cover - Black - Gas Gas/Husqvarna I04-5259B
MOOSE RACING
$88.95If you're running a Gas Gas or Husqvarna machine, the factory water pump cover is vulnerable to damage and heat stress during aggressive riding. This MOOSE Racing billet aluminum cover replaces that weak point with a precision-machined component that...09402049- SKU:
- 09402049
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
$88.95 -
MOOSE RACING Clutch Cylinder Guard - Gas Gas/Husqvarna/KTM 13-1123
MOOSE RACING
$42.95Hydraulic clutch cylinders are vulnerable to impact damage during aggressive riding—a single crash can leave you stranded. This MOOSE RACING guard protects that critical component with CNC-machined aluminum construction while its integrated knockdown bar...09500993- SKU:
- 09500993
- Availability:
- Ships Same Business Day
- Weight:
- 0.31 LBS
$42.95 -
MOOSE RACING Clutch Cylinder Guard - Gas Gas/KTM/Husqvarna 13-1223
MOOSE RACING
$42.95Hydraulic clutch cylinders are vulnerable to impact and chain strikes—damage means downtime and expensive repairs. This CNC-machined guard absorbs hits that would otherwise compromise your clutch system, keeping you on the track or trail. Built for Gas...09500994- SKU:
- 09500994
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
$42.95 -
MOOSE RACING Ignition Wire Guard - Sherco 27-9013
MOOSE RACING
$29.95Debris catching on exposed ignition wires is a common cause of misfires and electrical gremlins that can sideline your bike mid-race or trail ride. This MOOSE RACING Ignition Wire Guard shields the vulnerable wire above your ignition cover, preventing...09500995- SKU:
- 09500995
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
$29.95 -
MOOSE RACING Clutch Cover - Kawasaki D70-2474MB
MOOSE RACING
$179.95Your OEM clutch cover is a thermal bottleneck—heat buildup directly compromises clutch engagement and longevity. The MOOSE RACING clutch cover replaces this weak point with aircraft-grade aluminum construction that runs cooler and outlasts the factory...09402037- SKU:
- 09402037
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
$179.95 -
MOOSE RACING Clutch Cylinder Guard - Gas Gas/KTM/Husqvarna 13-1023
MOOSE RACING
$42.95Your hydraulic clutch cylinder is exposed to constant impact and debris on the trail—one hard crash or chain slap can leave you stranded. The MOOSE RACING Clutch Cylinder Guard shields this critical component from damage while keeping your chain under...09500992- SKU:
- 09500992
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
$42.95 -
Pro Circuit Water Pump Cover with Impeller for Kawasaki KX250 2021-2024 WPK21250
PRO CIRCUIT
$239.95Keep your KX250's cooling system operating at peak efficiency with a precision-engineered water pump cover that delivers measurable gains in water flow and thermal management. Factory pump covers often create unnecessary hydraulic resistance and leave...09402061- SKU:
- 09402061
- Availability:
- Ships Same Business Day
- Weight:
- 0.65 LBS
$239.95 -
VINTCO Crankshaft Assembly - Honda CR2012
VINTCO
$423.95A crankshaft is the backbone of your engine's reliability—this VINTCO assembly delivers the durability and precision required for consistent performance under sustained load. If you're rebuilding, upgrading, or replacing a worn component, forged steel...09210926- SKU:
- 09210926
- Availability:
- Ships Same Business Day
- Weight:
- 11.00 LBS
$423.95Qty in Cart: 0Quantity:Price:$423.95Subtotal: -
VINTCO Crankshaft Assembly - Honda CR2013
VINTCO
$423.95A failing or worn crankshaft compromises engine reliability and power delivery—replacing it with a precision-engineered assembly restores the structural integrity your Honda needs for consistent performance. The VINTCO CR2013 is forged for durability and...09210927- SKU:
- 09210927
- Availability:
- Ships Same Business Day
- Weight:
- 10.93 LBS
$423.95 -
VINTCO Crankshaft Assembly - Kawasaki CR2015
VINTCO
$416.95A crankshaft assembly is the backbone of your engine's reciprocating motion—it converts combustion force into rotational power that drives your wheels. The VINTCO CR2015 pairs precision engineering with heavy-duty materials designed to handle sustained...09210928- SKU:
- 09210928
- Availability:
- Ships Same Business Day
- Weight:
- 10.73 LBS
$416.95 -
VINTCO Crankshaft Assembly - Maico CR2011
VINTCO
$416.95A quality crankshaft assembly is the foundation of engine reliability and power delivery—especially in high-stress racing applications where failure isn't an option. The VINTCO CR2011 combines precision forging with heavy-duty construction to handle...09210925- SKU:
- 09210925
- Availability:
- Ships Same Business Day
- Weight:
- 11.96 LBS
$416.95 -
JE PISTONS Piston Kit 362954
JE PISTONS
$299.99Building a high-revving engine demands pistons engineered for the abuse that competition delivers. JE's 362954 kit combines precision forging with meticulous design to handle extreme boost, nitrous, and sustained RPM without compromise. When your...09106544- SKU:
- 09106544
- Availability:
- Ships Same Business Day
- Weight:
- 0.75 LBS
$299.99 -
JE PISTONS Piston Kit 373034
JE PISTONS
$389.99If you're building an engine for competition or extreme duty applications, piston quality directly impacts reliability and performance under peak loads. The JE PISTONS 373034 Kit delivers the strength and precision needed to withstand high RPM and...09106551- SKU:
- 09106551
- Availability:
- Ships Same Business Day
- Weight:
- 0.60 LBS
$389.99 -
JE PISTONS Piston Kit 373035
JE PISTONS
$389.99When you're pushing your engine to the limit in competition, stock pistons won't cut it. The JE Piston Kit 373035 is purpose-built for extreme applications where reliability and performance are non-negotiable—delivering the strength and precision you...09106552- SKU:
- 09106552
- Availability:
- Ships Same Business Day
- Weight:
- 0.79 LBS
$389.99 -
MOOSE RACING Piston Kit - 78.00 mm - Honda MP2000C
MOOSE RACING
$326.95If you're pushing your Honda MP2000C to its limits, stock pistons become your weak point. The MOOSE RACING Piston Kit delivers the strength and precision you need to run aggressive boost levels and high RPMs without sacrificing reliability. Built with...09106465- SKU:
- 09106465
- Availability:
- Ships Same Business Day
- Weight:
- 0.90 LBS
$326.95 -
MOOSE RACING Piston Kit - 96.00 mm - Honda MP2029
MOOSE RACING
$326.95A quality piston kit is fundamental to reliable engine performance and longevity. The MOOSE Racing MP2029 combines precision forging with thoughtful internal engineering to deliver consistent power output while resisting detonation and wear. Whether...09106467- SKU:
- 09106467
- Availability:
- Ships Same Business Day
- Weight:
- 1.00 LBS
$326.95Qty in Cart: 0Quantity:Price:$326.95Subtotal: -
MOOSE RACING Piston Kit - 97.00 mm - Yamaha MPX1111
MOOSE RACING
$421.95When you're pushing your Yamaha to the limit, a quality piston kit is non-negotiable. The MOOSE RACING 97.00 mm Piston Kit delivers the strength and precision needed for reliable high-RPM performance, with forged construction that resists detonation and...09106521- SKU:
- 09106521
- Availability:
- Ships Same Business Day
- Weight:
- 1.10 LBS
$421.95 -
MOOSE RACING Piston Kit - 77.00 mm - Kawasaki M3023C
MOOSE RACING
$177.95If you're rebuilding a high-revving Kawasaki engine or looking to restore OEM performance, piston integrity is non-negotiable. The MOOSE RACING Piston Kit delivers forged strength and precision engineering to handle sustained power delivery without...09106470- SKU:
- 09106470
- Availability:
- Ships Same Business Day
- Weight:
- 0.80 LBS
$177.95Qty in Cart: 0Quantity:Price:$177.95Subtotal: -
MOOSE RACING Piston Kit - 96.00 mm - Honda MP2009
MOOSE RACING
$326.95High-performance pistons are critical to engine reliability under extreme conditions—cheap alternatives fail catastrophically. The MOOSE RACING Piston Kit delivers the strength and precision engineering required for sustained high-RPM operation, whether...09106466- SKU:
- 09106466
- Availability:
- Ships Same Business Day
- Weight:
- 1.15 LBS
$326.95
