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
-
On Sale
ATHENA Complete Gasket Kit - Suzuki P400510850069
ATHENA
MSRP: $63.95Now: $58.00Was: $63.95Superior-quality gasket sets from Athena, Head gaskets feature rubber-coated spring steel construction, Soft steel base gaskets are rubber coated, Steel core materials feature high springback and superior tensile strength, Revolutionary transparent...09342005- SKU:
- 09342005
- Availability:
- Ships Same Business Day
- Weight:
- 0.32 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
MSRP: $63.95Now: $58.00Was: $63.95 -
On Sale
ATHENA Complete Gasket Kit - Yamaha P400485850072
ATHENA
MSRP: $69.95Now: $63.00Was: $69.95Superior-quality gasket sets from Athena, Head gaskets feature rubber-coated spring steel construction, Soft steel base gaskets are rubber coated, Steel core materials feature high springback and superior tensile strength, Revolutionary transparent...09342008- SKU:
- 09342008
- Availability:
- Ships Same Business Day
- Weight:
- 0.23 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
MSRP: $69.95Now: $63.00Was: $69.95Qty in Cart: 0Quantity:Price:MSRP: $69.95Now: $63.00Was: $69.95Subtotal: -
On Sale
ATHENA Complete Gasket Kit - Yamaha P400485850162
ATHENA
MSRP: $46.50Now: $42.00Was: $46.50Superior-quality gasket sets from Athena, Head gaskets feature rubber-coated spring steel construction, Soft steel base gaskets are rubber coated, Steel core materials feature high springback and superior tensile strength, Revolutionary transparent...09342011- SKU:
- 09342011
- Availability:
- Ships Same Business Day
- Weight:
- 0.31 LBS
- TYPE:
- COMPLETE
- UNITS:
- KIT
- ENGINE TYPE:
- -
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- STREET
MSRP: $46.50Now: $42.00Was: $46.50Qty in Cart: 0Quantity:Price:MSRP: $46.50Now: $42.00Was: $46.50Subtotal: -
On Sale
ATHENA Race Gasket Kit - KTM/Husqvarna R2706-045
ATHENA
MSRP: $27.95Now: $25.00Was: $27.95Specifically designed for the pro, semi-pro and amateur rider who freshens up their engine prior to a race or during mid-season, Kits include a top-of-the line MLSS head gasket and two or more premium-quality base gaskets of different thicknesses to...09342828- SKU:
- 09342828
- Availability:
- Ships Same Business Day
- Weight:
- 0.14 LBS
- PRODUCT NAME:
- GASKET KIT
- STYLE:
- RACE
- TYPE:
- TOP END
- MATERIAL:
- RUBBER
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $27.95Now: $25.00Was: $27.95 -
On Sale
ATHENA Race Gasket Kit - Yamaha R4856-039
ATHENA
MSRP: $53.95Now: $49.00Was: $53.95Specifically designed for the pro, semi-pro and amateur rider who freshens up their engine prior to a race or during mid-season, Kits include a top-of-the line MLSS head gasket and two or more premium-quality base gaskets of different thicknesses to...09342839- SKU:
- 09342839
- Availability:
- Ships Same Business Day
- Weight:
- 0.24 LBS
- STYLE:
- RACE
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET KIT
- MATERIAL:
- RUBBER
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $53.95Now: $49.00Was: $53.95Qty in Cart: 0Quantity:Price:MSRP: $53.95Now: $49.00Was: $53.95Subtotal: -
On Sale
ATHENA Race Gasket Kit - YZ250 R4856-267
ATHENA
MSRP: $18.95Now: $17.00Was: $18.95Specifically designed for the pro, semi-pro and amateur rider who freshens up their engine prior to a race or during mid-season, Kits include a top-of-the line MLSS head gasket and two or more premium-quality base gaskets of different thicknesses to...09342845- SKU:
- 09342845
- Availability:
- Ships Same Business Day
- Weight:
- 0.14 LBS
- STYLE:
- RACE
- MATERIAL:
- RUBBER
- UNITS:
- KIT
- MATERIAL:
- STEEL
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
MSRP: $18.95Now: $17.00Was: $18.95Qty in Cart: 0Quantity:Price:MSRP: $18.95Now: $17.00Was: $18.95Subtotal: -
On Sale
ATHENA Top End Gasket Kit - 50SX P400270600049
ATHENA
MSRP: $72.95Now: $66.00Was: $72.95Specifically designed for the pro, semi-pro and amateur rider who freshens up their engine prior to a race or during midseason. Gives the rider a choice of using standard gas with stock compression, or race gas with a higher compression. Kits do not...09342856- SKU:
- 09342856
- Availability:
- Ships Same Business Day
- Weight:
- 0.12 LBS
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
MSRP: $72.95Now: $66.00Was: $72.95 -
On Sale
ATHENA Race Gasket Kit - YZ450F R4856-188
ATHENA
MSRP: $91.95Now: $83.00Was: $91.95Specifically designed for the pro, semi-pro and amateur rider who freshens up their engine prior to a race or during mid-season, Kits include a top-of-the line MLSS head gasket and two or more premium-quality base gaskets of different thicknesses to...09343163- SKU:
- 09343163
- Availability:
- Ships Same Business Day
- Weight:
- 0.24 LBS
- MATERIAL:
- RUBBER
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
- STYLE:
- RACE
MSRP: $91.95Now: $83.00Was: $91.95 -
On Sale
ATHENA Top End Gasket Kit - Kawasaki P400250600065
ATHENA
MSRP: $50.95Now: $46.00Was: $50.95Specifically designed for the pro, semi-pro and amateur rider who freshens up their engine prior to a race or during midseason. Gives the rider a choice of using standard gas with stock compression, or race gas with a higher compression. Kits do not...09343164- SKU:
- 09343164
- Availability:
- Ships Same Business Day
- Weight:
- 0.05 LBS
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- TOP END
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 2-STROKE
- UNITS:
- KIT
MSRP: $50.95Now: $46.00Was: $50.95 -
On Sale
ATHENA Top End Gasket Kit - Kawasaki P400250600030
ATHENA
MSRP: $47.95Now: $43.00Was: $47.95Specifically designed for the pro, semi-pro and amateur rider who freshens up their engine prior to a race or during midseason. Gives the rider a choice of using standard gas with stock compression, or race gas with a higher compression. Kits do not...09343166- SKU:
- 09343166
- Availability:
- Ships Same Business Day
- Weight:
- 0.20 LBS
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- TOP END
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $47.95Now: $43.00Was: $47.95 -
On Sale
ATHENA Top End Gasket Kit - KTM P400270600072
ATHENA
MSRP: $147.95Now: $133.00Was: $147.95Specifically designed for the pro, semi-pro and amateur rider who freshens up their engine prior to a race or during midseason. Gives the rider a choice of using standard gas with stock compression, or race gas with a higher compression. Kits do not...09343169- SKU:
- 09343169
- Availability:
- Ships Same Business Day
- Weight:
- 0.26 LBS
- PRODUCT NAME:
- GASKET KIT
- UNITS:
- KIT
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
MSRP: $147.95Now: $133.00Was: $147.95 -
On Sale
ATHENA Complete Gasket Kit - Yamaha P400485900188
ATHENA
MSRP: $182.95Now: $165.00Was: $182.95Superior-quality gasket sets from Athena, Head gaskets feature rubber-coated spring steel construction, Soft steel base gaskets are rubber coated, Steel core materials feature high springback and superior tensile strength, Revolutionary transparent...09343174- SKU:
- 09343174
- Availability:
- Ships Same Business Day
- Weight:
- 0.52 LBS
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
- TYPE:
- COMPLETE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $182.95Now: $165.00Was: $182.95 -
On Sale
ATHENA Water Pump Gasket Kit - Suzuki P400510470005
ATHENA
MSRP: $42.95Now: $39.00Was: $42.95Include water pump gasket, clutch cover gasket, water pump shaft oil seals and washers, Kit contents will vary slightly based on application, Kits do not contain replacement bearings09345162- SKU:
- 09345162
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- TYPE:
- WATER PUMP
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET KIT
MSRP: $42.95Now: $39.00Was: $42.95Qty in Cart: 0Quantity:Price:MSRP: $42.95Now: $39.00Was: $42.95Subtotal: -
On Sale
ATHENA Cylinder Kit - YZ125 - 58mm P400485100030
ATHENA
MSRP: $1,223.95Now: $1,102.00Was: $1,223.95Kits include aluminum cylinder with nickel-carbide coating designed with larger water jackets, Forged piston with molybdenum coating, Special gasket kit, Easy-to-follow step-by-step installation instructions, All are bolt-on; no machining required09310146- SKU:
- 09310146
- Availability:
- Ships Same Business Day
- Weight:
- 5.16 LBS
- CYLINDER BORE COATING:
- NICKEL-CARBIDE
- DISPLACEMENT:
- 144 CC
- ENGINE TYPE:
- 2-STROKE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE SIZE METRIC:
- 58.00 MM
- MATERIAL:
- ALUMINUM
- PRODUCT NAME:
- CYLINDER KIT
- STYLE:
- BIG BORE
MSRP: $1,223.95Now: $1,102.00Was: $1,223.95 -
On Sale
ATHENA Piston Kit - Yamaha/Malaguti S4C04760006A
ATHENA
MSRP: $61.95Now: $56.00Was: $61.95Piston kits include piston, rings, wrist pin, and circlips09100581- SKU:
- 09100581
- Availability:
- Ships Same Business Day
- Weight:
- 0.24 LBS
- BORE - OVERSIZE:
- STANDARD
- BORE - OVERSIZE METRIC:
- STANDARD
- RIDING STYLE:
- STREET
- BORE SIZE METRIC:
- 47.66 MM
- PISTON MATERIAL:
- ALUMINUM
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- KIT
MSRP: $61.95Now: $56.00Was: $61.95 -
On Sale
ATHENA Piston Kit S4F06640018A
ATHENA
MSRP: $187.95Now: $169.00Was: $187.95Two-stroke pistons are made from 4032 silicium, Four-stroke pistons are made from 2618 silicium - the same material used to produce Formula 1 pistons, Both include 3% copper in materials for better heat resistance, All pistons are forged using a...09100627- SKU:
- 09100627
- Availability:
- Ships Same Business Day
- Weight:
- 0.67 LBS
- BORE SIZE METRIC:
- 66.34 MM
- COMPRESSION RATIO IMPERIAL:
- STOCK
- DISPLACEMENT:
- 250 CC
- PRODUCT NAME:
- PISTON KIT
- RIDING STYLE:
- STREET
- TYPE:
- A
- ENGINE TYPE:
- 2-STROKE
- PISTON HEAD SHAPE:
- DOMED
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $187.95Now: $169.00Was: $187.95Qty in Cart: 0Quantity:Price:MSRP: $187.95Now: $169.00Was: $187.95Subtotal: -
On Sale
ATHENA Piston Kit S4F06640019A
ATHENA
MSRP: $173.95Now: $157.00Was: $173.95Two-stroke pistons are made from 4032 silicium, Four-stroke pistons are made from 2618 silicium - the same material used to produce Formula 1 pistons, Both include 3% copper in materials for better heat resistance, All pistons are forged using a...09100641- SKU:
- 09100641
- Availability:
- Ships Same Business Day
- Weight:
- 0.69 LBS
- BORE SIZE METRIC:
- 66.34 MM
- COMPRESSION RATIO IMPERIAL:
- STOCK
- PRODUCT NAME:
- PISTON KIT
- UNITS:
- KIT
- PISTON HEAD SHAPE:
- DOMED
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- ENGINE TYPE:
- 2-STROKE
- DISPLACEMENT:
- 249 CC
- TYPE:
- A
MSRP: $173.95Now: $157.00Was: $173.95Qty in Cart: 0Quantity:Price:MSRP: $173.95Now: $157.00Was: $173.95Subtotal: -
On Sale
ATHENA Piston Kit S5F08200001A
ATHENA
MSRP: $245.95Now: $221.00Was: $245.95Includes rings, clips and pin, Easy-to-follow step-by-step installation instructions09100646- SKU:
- 09100646
- Availability:
- Ships Same Business Day
- Weight:
- 0.56 LBS
- PISTON DIAMETER METRIC:
- 81.95 MM
- STYLE:
- BIG BORE
- PISTON SIZE METRIC:
- STANDARD SIZE A
- PRODUCT NAME:
- PISTON
- COMPRESSION RATIO IMPERIAL:
- 13.1:1
- ENGINE TYPE:
- 4-STROKE
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
MSRP: $245.95Now: $221.00Was: $245.95 -
On Sale
ATHENA Piston Kit S4C05800001A
ATHENA
MSRP: $242.95Now: $219.00Was: $242.95Includes rings, clips and pin, Easy-to-follow step-by-step installation instructions09100648- SKU:
- 09100648
- Availability:
- Ships Same Business Day
- Weight:
- 0.42 LBS
- STYLE:
- BIG BORE
- ENGINE TYPE:
- 2-STROKE
- PISTON DIAMETER METRIC:
- 57.94 MM
- PISTON SIZE METRIC:
- STANDARD SIZE A
- COMPRESSION RATIO IMPERIAL:
- 14.0:1
- PRODUCT NAME:
- PISTON
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- EACH
MSRP: $242.95Now: $219.00Was: $242.95Qty in Cart: 0Quantity:Price:MSRP: $242.95Now: $219.00Was: $242.95Subtotal: -
On Sale
ATHENA Piston Kit S4C04850001B
ATHENA
MSRP: $89.95Now: $81.00Was: $89.95Two-stroke pistons are made from 4032 silicium, Four-stroke pistons are made from 2618 silicium - the same material used to produce Formula 1 pistons, Both include 3% copper in materials for better heat resistance, All pistons are forged using a...09101418- SKU:
- 09101418
- Availability:
- Ships Same Business Day
- Weight:
- 0.32 LBS
- DISPLACEMENT:
- 85 CC
- ENGINE TYPE:
- 2-STROKE
- PISTON HEAD SHAPE:
- DOMED
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- BORE SIZE METRIC:
- 48.46 MM
- COMPRESSION RATIO IMPERIAL:
- STOCK
- PRODUCT NAME:
- PISTON KIT
- TYPE:
- B
MSRP: $89.95Now: $81.00Was: $89.95Qty in Cart: 0Quantity:Price:MSRP: $89.95Now: $81.00Was: $89.95Subtotal:
