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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Cylinder Works Standard Bore Cylinder Kit for Yamaha YZ250F 2005-2007 20002-K02
CYLINDER WORKS
$395.95If you're running a 2005-2007 Yamaha YZ250F and want to restore or upgrade cylinder performance without machine shop downtime, the Cylinder Works Standard Bore Kit is your direct solution. The nickel...09310131- SKU:
- 09310131
- Availability:
- Ships Same Business Day
- Weight:
- 2.90 LBS
- BORE SIZE METRIC:
- 77.00 MM
- STYLE:
- STANDARD
- ENGINE TYPE:
- 4-CYCLE
- CYLINDER DIAMETER METRIC:
- 77.00 MM
- UNITS:
- EACH
- CYLINDER DIAMETER:
- 77,00 MM
- PRODUCT NAME:
- CYLINDER
- RIDING STYLE:
- OFF-ROAD
$395.95 -
Cylinder Works Big Bore Kit Honda TRX450R 2004-2005 479cc 10.5:1 11003-K01
CYLINDER WORKS
$809.95A big bore upgrade is one of the most effective ways to unlock additional displacement and power from your TRX450R without compromising reliability. The Cylinder Works 479cc kit delivers a...09310133- SKU:
- 09310133
- Availability:
- Ships Same Business Day
- Weight:
- 4.47 LBS
- COMPRESSION RATIO IMPERIAL:
- 10.5:1
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER METRIC:
- 97.00 MM
- OVERBORE METRIC:
- +3.00 MM
- ENGINE TYPE:
- 4-CYCLE
- RIDING STYLE:
- ATV
- CYLINDER DIAMETER:
- 97,00 MM
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- DISPLACEMENT:
- 479 CC
- UNITS:
- KIT
$809.95 -
Cylinder Works Yamaha WR450F YFZ450R YZ450F 2007-2014 High Compression Cylinder Kit 20003-K01HC
CYLINDER WORKS
$788.95If you're running a 2007-2014 Yamaha WR450F, YFZ450R, or YZ450F, a worn or damaged cylinder directly compromises compression, throttle response, and overall engine reliability. The Cylinder Works...09310299- SKU:
- 09310299
- Availability:
- Ships Same Business Day
- Weight:
- 4.38 LBS
- COMPRESSION RATIO IMPERIAL:
- 13.5:1
- CYLINDER DIAMETER METRIC:
- 95.00 MM
- DISPLACEMENT:
- 449 CC
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- UNITS:
- KIT
- CYLINDER DIAMETER:
- 95,00 MM
- STYLE:
- HIGH COMPRESSION
$788.95 -
Cylinder Works High Compression Cylinder Kit for Suzuki LT-R450 2006-2009 40002-K01HC
CYLINDER WORKS
$743.95If you're serious about extracting more power from your LT-R450, a high-compression cylinder kit is one of the most effective bolt-on upgrades available. This Cylinder Works kit delivers a...09310303- SKU:
- 09310303
- Availability:
- Ships Same Business Day
- Weight:
- 4.30 LBS
- COMPRESSION RATIO IMPERIAL:
- 13.0:1
- DISPLACEMENT:
- 449 CC
- ENGINE TYPE:
- 4-CYCLE
- STYLE:
- HIGH COMPRESSION
- CYLINDER DIAMETER:
- 95,50 MM
- RIDING STYLE:
- ATV
- UNITS:
- KIT
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER METRIC:
- 95.50 MM
- PRODUCT NAME:
- CYLINDER KIT
$743.95Qty in Cart: 0Quantity:Price:$743.95Subtotal: -
Cylinder Works Big Bore Kit Yamaha YZ250F 2001-2013 21002-K01
CYLINDER WORKS
$836.95If you're running a YZ250F and want to unlock measurable gains in displacement and power output, a big bore kit is one of the most direct upgrades available. The Cylinder Works 21002-K01 delivers a...09310121- SKU:
- 09310121
- Availability:
- Ships Same Business Day
- Weight:
- 3.37 LBS
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- DISPLACEMENT:
- 269 CC
- OVERBORE METRIC:
- +3.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- CYLINDER DIAMETER METRIC:
- 80.00 MM
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- CYLINDER DIAMETER:
- 80,00 MM
$836.95 -
CYLINDER WORKS Cylinder - Standard 30001
CYLINDER WORKS
$410.95A worn or damaged cylinder can severely limit your engine's efficiency and reliability on the track or in the shop. The CYLINDER WORKS Standard 30001 delivers a ready-to-install replacement that...09310130- SKU:
- 09310130
- Availability:
- Ships Same Business Day
- Weight:
- 2.50 LBS
- RIDING STYLE:
- OFF-ROAD
- CYLINDER DIAMETER METRIC:
- 77.00 MM
- STYLE:
- STANDARD
- CYLINDER DIAMETER:
- 77,00 MM
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER
- BORE SIZE METRIC:
- 77.00 MM
- UNITS:
- EACH
$410.95 -
Cylinder Works Standard Bore Cylinder for Yamaha YFZ450 2004-2009 2012-2013 20001
CYLINDER WORKS
$410.95Your YFZ450's cylinder is the foundation of reliable power delivery—when it wears, you lose compression, efficiency, and overall engine performance. The Cylinder Works Standard Bore Cylinder (20001)...09310132- SKU:
- 09310132
- Availability:
- Ships Same Business Day
- Weight:
- 3.30 LBS
- CYLINDER DIAMETER:
- 95,00 MM
- OVERBORE METRIC:
- STANDARD
- STYLE:
- STANDARD
- COMPRESSION RATIO IMPERIAL:
- 12.0:1
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- DISPLACEMENT:
- 449 CC
- PRODUCT NAME:
- CYLINDER
- CYLINDER DIAMETER METRIC:
- 95.00 MM
- RIDING STYLE:
- ATV
- UNITS:
- EACH
- ENGINE TYPE:
- 4-CYCLE
$410.95 -
Cylinder Works Big Bore Kit for Suzuki DR-Z400 2000-2004 41001-K01
CYLINDER WORKS
$837.95If you're running a stock DR-Z400, you're leaving power on the table. The Cylinder Works Big Bore Kit delivers a straightforward displacement increase with zero guesswork—everything you need arrives...09310135- SKU:
- 09310135
- Availability:
- Ships Same Business Day
- Weight:
- 4.44 LBS
- COMPRESSION RATIO IMPERIAL:
- 11.3:1
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- STREET
- STYLE:
- BIG BORE
- CYLINDER DIAMETER:
- 94,00 MM
- DISPLACEMENT:
- 434 CC
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- OVERBORE METRIC:
- +4.00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- CYLINDER DIAMETER METRIC:
- 94.00 MM
- RIDING STYLE:
- ATV
$837.95 -
Cylinder Works Standard Bore Cylinder Kit for Suzuki DR-Z400S 2000-2022 40001-K01
CYLINDER WORKS
$440.95The stock cylinder on your DR-Z400S will eventually wear, leading to lost compression, increased blow-by, and sluggish performance. The Cylinder Works Standard Bore Cylinder Kit restores your engine...09310139- SKU:
- 09310139
- Availability:
- Ships Same Business Day
- Weight:
- 3.61 LBS
- CYLINDER DIAMETER METRIC:
- 90.00 MM
- RIDING STYLE:
- ATV
- UNITS:
- EACH
- CYLINDER DIAMETER:
- 90,00 MM
- PRODUCT NAME:
- CYLINDER
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- STANDARD
- ENGINE TYPE:
- 4-CYCLE
- RIDING STYLE:
- STREET
$440.95 -
Cylinder Works Big Bore Cylinder Kit for Honda CRF150R 2012-2020 11004-K02
CYLINDER WORKS
$694.95If you're running a Honda CRF150R and want measurable gains in displacement and power output, a big bore kit is one of the most direct paths forward. The Cylinder Works 11004-K02 delivers bolt-on...09310485- SKU:
- 09310485
- Availability:
- Ships Same Business Day
- Weight:
- 2.80 LBS
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- CYLINDER DIAMETER:
- 68,00 MM
- DISPLACEMENT:
- 159 CC
- OVERBORE METRIC:
- +2.00 MM
- PRODUCT NAME:
- CYLINDER KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- COMPRESSION RATIO IMPERIAL:
- 11.7:1
- STYLE:
- BIG BORE
- CYLINDER DIAMETER METRIC:
- 68.00 MM
- ENGINE TYPE:
- 4-CYCLE
$694.95 -
Cylinder Works Big Bore Cylinder Kit for 2009-2015 Kawasaki KX450F 31011-K01
CYLINDER WORKS
$786.95If you're serious about extracting maximum displacement from your KX450F, the Cylinder Works Big Bore Kit delivers tangible power gains without the machine shop hassle. This bolt-on upgrade pairs a...09310603- SKU:
- 09310603
- Availability:
- Ships Same Business Day
- Weight:
- 3.95 LBS
- DISPLACEMENT:
- 469 CC
- OVERBORE METRIC:
- +2.00 MM
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
- UNITS:
- KIT
- COMPRESSION RATIO IMPERIAL:
- 12.5:1
- RIDING STYLE:
- OFF-ROAD
- CYLINDER DIAMETER:
- 98,00 MM
- CYLINDER DIAMETER METRIC:
- 98.00 MM
- ENGINE TYPE:
- 4-CYCLE
$786.95 -
Cylinder Works Standard Bore Cylinder Kit for Polaris RZR XP 900 2011-2013 60001-K02
CYLINDER WORKS
$1,204.95When your RZR XP 900's engine is ready for more, a complete cylinder kit eliminates the guesswork and delivers measurable gains in displacement and reliability. This Cylinder Works kit arrives as a...09310657- SKU:
- 09310657
- Availability:
- Ships Same Business Day
- Weight:
- 10.00 LBS
- COMPRESSION RATIO IMPERIAL:
- 10.6:1
- CYLINDER DIAMETER:
- 93,00 MM
- ENGINE TYPE:
- 4-CYCLE
- PRODUCT NAME:
- CYLINDER KIT
- CYLINDER BORE COATING:
- NICKEL-SILICON CARBIDE
- DISPLACEMENT:
- 875 CC
- UNITS:
- KIT
- CYLINDER DIAMETER METRIC:
- 93.00 MM
- RIDING STYLE:
- UTV
- STYLE:
- STANDARD
$1,204.95 -
DEL WEST Intake Valves CRF250RIV10NDHF
DEL WEST
$155.95If you're building a CRF250R engine that demands maximum flow and rpm capability, DEL WEST intake valves are engineered for zero compromises. The 50-degree seat angle and flat valve face eliminate...09262469- SKU:
- 09262469
- Availability:
- Ships Same Business Day
- Weight:
- 0.06 LBS
- MATERIAL:
- TITANIUM
- APPLICATION:
- INTAKE
- PRODUCT NAME:
- VALVE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
$155.95 -
On Sale
DEL WEST Exhaust Valves CRF250REV10NDHF
DEL WEST
MSRP: $155.95Now: $100.00Was: $155.95If you're building an engine that demands maximum airflow and can handle higher RPMs, the DEL WEST Exhaust Valves are engineered for serious competitors who refuse compromise. The 50-degree seat...09262470- SKU:
- 09262470
- Availability:
- Ships Same Business Day
- Weight:
- 0.11 LBS
- MATERIAL:
- TITANIUM
- APPLICATION:
- EXHAUST
- PRODUCT NAME:
- VALVE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
MSRP: $155.95Now: $100.00Was: $155.95 -
On Sale
DEL WEST Exhaust Valve DWCRF450REV09ND
DEL WEST
MSRP: $155.95Now: $100.00Was: $155.95Off-road racing demands exhaust components that can withstand extreme conditions without sacrificing performance or reliability. The DEL WEST Exhaust Valve DWCRF450REV09ND is engineered specifically...09262471- SKU:
- 09262471
- Availability:
- Ships Same Business Day
- Weight:
- 0.06 LBS
- MATERIAL:
- TITANIUM
- PRODUCT NAME:
- VALVE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
- APPLICATION:
- EXHAUST
MSRP: $155.95Now: $100.00Was: $155.95 -
DEL WEST Valve Spring Retainer DW-H-RX01-S
DEL WEST
$71.95When you're pushing your engine to the limit, valve spring retainers become a critical failure point. The DEL WEST DW-H-RX01-S is engineered from premium titanium to withstand extreme RPMs and valve...09262472- SKU:
- 09262472
- Availability:
- Ships Same Business Day
- Weight:
- 0.06 LBS
- APPLICATION:
- INTAKE
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- RETAINER
- TYPE:
- VALVE SPRING
- UNITS:
- EACH
- APPLICATION:
- EXHAUST
$71.95 -
DEL WEST Valve Spring Retainer DW-H-RX02-S
DEL WEST
$48.95Del West valve spring retainers are engineered for maximum durability in high-RPM racing applications where standard components fail. Built by the same manufacturer trusted by NASCAR, Formula One,...09262473- SKU:
- 09262473
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- APPLICATION:
- INTAKE
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- VALVE SPRING
- APPLICATION:
- EXHAUST
- PRODUCT NAME:
- RETAINER
- UNITS:
- EACH
$48.95Qty in Cart: 0Quantity:Price:$48.95Subtotal: -
DEL WEST Exhaust Valve DW-CRF250R-EV08
DEL WEST
$155.95If you're running a CRF250R in competition or high-stress riding conditions, valve reliability directly impacts your engine's performance window and race-day consistency. DEL WEST exhaust valves are...09261042- SKU:
- 09261042
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- MATERIAL:
- TITANIUM
- UNITS:
- EACH
- APPLICATION:
- EXHAUST
- PRODUCT NAME:
- VALVE
- RIDING STYLE:
- OFF-ROAD
$155.95 -
DEL WEST Exhaust Valve DW-CRF250R-EV10
DEL WEST
$155.95If you're serious about off-road performance, your exhaust valve needs to match your ambition. DEL WEST has built its reputation on valves that survive the punishing conditions of competition—high...09261043- SKU:
- 09261043
- Availability:
- Ships Same Business Day
- Weight:
- 0.07 LBS
- APPLICATION:
- EXHAUST
- UNITS:
- EACH
- PRODUCT NAME:
- VALVE
- MATERIAL:
- TITANIUM
- RIDING STYLE:
- OFF-ROAD
$155.95 -
DEL WEST Intake Valve DW-CRF250R-IV04
DEL WEST
$171.95Competition-proven intake valves are the foundation of reliable top-end performance, especially in high-RPM off-road environments where factory components fall short. DEL WEST's CRF250R intake valve...09261044- SKU:
- 09261044
- Availability:
- Ships Same Business Day
- Weight:
- 0.07 LBS
- UNITS:
- EACH
- APPLICATION:
- INTAKE
- MATERIAL:
- TITANIUM
- PRODUCT NAME:
- VALVE
- RIDING STYLE:
- OFF-ROAD
$171.95
