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 Water Pump Gasket Kit - Yamaha P400485475009
ATHENA
MSRP: $39.95Now: $36.00Was: $39.95Include 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 bearings09346091- SKU:
- 09346091
- Availability:
- Ships Same Business Day
- Weight:
- 0.25 LBS
- TYPE:
- WATER PUMP
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $39.95Now: $36.00Was: $39.95 -
On Sale
ATHENA Water Pump Gasket Kit - Yamaha P400485475010
ATHENA
MSRP: $39.95Now: $36.00Was: $39.95Include 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 bearings09346092- SKU:
- 09346092
- Availability:
- Ships Same Business Day
- Weight:
- 0.10 LBS
- TYPE:
- WATER PUMP
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
MSRP: $39.95Now: $36.00Was: $39.95Qty in Cart: 0Quantity:Price:MSRP: $39.95Now: $36.00Was: $39.95Subtotal: -
On Sale
ATHENA Complete Gasket Kit - Kawasaki/Suzuki P400250850016
ATHENA
MSRP: $132.95Now: $120.00Was: $132.95Superior-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...09340352- SKU:
- 09340352
- Availability:
- Ships Same Business Day
- Weight:
- 0.28 LBS
- ENGINE TYPE:
- -
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
MSRP: $132.95Now: $120.00Was: $132.95Qty in Cart: 0Quantity:Price:MSRP: $132.95Now: $120.00Was: $132.95Subtotal: -
On Sale
ATHENA Gasket Kit - KX250F/RMZ250 P400510160004
ATHENA
MSRP: $104.95Now: $94.00Was: $104.95Kits 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 required09340359- SKU:
- 09340359
- Availability:
- Ships Same Business Day
- Weight:
- 0.12 LBS
- BORE SIZE:
- 83,00 MM
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- GASKET KIT
- BORE SIZE METRIC:
- 83.00 MM
- TYPE:
- TOP END
MSRP: $104.95Now: $94.00Was: $104.95 -
On Sale
ATHENA Complete Gasket Kit - KTM P400270850220/1
ATHENA
MSRP: $91.95Now: $83.00Was: $91.95Superior-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...09340221- SKU:
- 09340221
- Availability:
- Ships Same Business Day
- Weight:
- 0.50 LBS
- ENGINE TYPE:
- 2-STROKE
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- UNITS:
- KIT
- RIDING STYLE:
- STREET
- PRODUCT NAME:
- GASKET KIT
MSRP: $91.95Now: $83.00Was: $91.95Qty in Cart: 0Quantity:Price:MSRP: $91.95Now: $83.00Was: $91.95Subtotal: -
On Sale
ATHENA Top End Gasket Kit - Husqvarna P400220600252
ATHENA
MSRP: $63.95Now: $58.00Was: $63.95Specifically 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...09341789- SKU:
- 09341789
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- TYPE:
- TOP END
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET KIT
MSRP: $63.95Now: $58.00Was: $63.95 -
On Sale
ATHENA Top End Gasket Kit - Honda P400210600207
ATHENA
MSRP: $67.95Now: $61.00Was: $67.95Specifically 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...09341969- SKU:
- 09341969
- Availability:
- Ships Same Business Day
- Weight:
- 0.18 LBS
- PRODUCT NAME:
- GASKET KIT
- MATERIAL:
- RUBBER
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
MSRP: $67.95Now: $61.00Was: $67.95Qty in Cart: 0Quantity:Price:MSRP: $67.95Now: $61.00Was: $67.95Subtotal: -
On Sale
ATHENA Top End Gasket Kit - Honda P400210600192
ATHENA
MSRP: $54.95Now: $49.00Was: $54.95Specifically 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...09341972- SKU:
- 09341972
- Availability:
- Ships Same Business Day
- Weight:
- 0.13 LBS
- TYPE:
- TOP END
- UNITS:
- KIT
- MATERIAL:
- RUBBER
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET KIT
MSRP: $54.95Now: $49.00Was: $54.95 -
On Sale
ATHENA Complete Gasket Kit - Kawasaki P400250850047
ATHENA
MSRP: $204.95Now: $184.00Was: $204.95Superior-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...09341997- SKU:
- 09341997
- Availability:
- Ships Same Business Day
- Weight:
- 0.41 LBS
- ENGINE TYPE:
- -
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
- PRODUCT NAME:
- GASKET KIT
MSRP: $204.95Now: $184.00Was: $204.95Qty in Cart: 0Quantity:Price:MSRP: $204.95Now: $184.00Was: $204.95Subtotal: -
On Sale
ATHENA Race Gasket Kit - YZ 125 R4856-118
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...09342840- SKU:
- 09342840
- Availability:
- Ships Same Business Day
- Weight:
- 0.15 LBS
- STYLE:
- RACE
- TYPE:
- TOP END
- PRODUCT NAME:
- GASKET KIT
- MATERIAL:
- RUBBER
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
MSRP: $18.95Now: $17.00Was: $18.95 -
On Sale
ATHENA Race Gasket Kit - YZ80/85 R4856-089
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...09342843- SKU:
- 09342843
- Availability:
- Ships Same Business Day
- Weight:
- 0.14 LBS
- MATERIAL:
- RUBBER
- MATERIAL:
- STEEL
- RIDING STYLE:
- OFF-ROAD
- PRODUCT NAME:
- GASKET KIT
- STYLE:
- RACE
- UNITS:
- KIT
- TYPE:
- TOP END
MSRP: $18.95Now: $17.00Was: $18.95Qty in Cart: 0Quantity:Price:MSRP: $18.95Now: $17.00Was: $18.95Subtotal: -
On Sale
ATHENA Gasket Kit P400270160059
ATHENA
MSRP: $68.95Now: $62.00Was: $68.95Kits 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 required09342898- SKU:
- 09342898
- Availability:
- Ships Same Business Day
- Weight:
- 0.17 LBS
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
- DISPLACEMENT:
- 277 CC
- BORE SIZE:
- 80,00 MM
- BORE SIZE METRIC:
- 80.00 MM
- PRODUCT NAME:
- GASKET KIT
MSRP: $68.95Now: $62.00Was: $68.95Qty in Cart: 0Quantity:Price:MSRP: $68.95Now: $62.00Was: $68.95Subtotal: -
On Sale
ATHENA Complete Gasket Kit - Kawasaki P400250900065
ATHENA
MSRP: $131.95Now: $119.00Was: $131.95Superior-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...09343165- SKU:
- 09343165
- Availability:
- Ships Same Business Day
- Weight:
- 0.30 LBS
- UNITS:
- KIT
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- COMPLETE
MSRP: $131.95Now: $119.00Was: $131.95Qty in Cart: 0Quantity:Price:MSRP: $131.95Now: $119.00Was: $131.95Subtotal: -
On Sale
ATHENA Top End Gasket Kit - Yamaha P400485600188
ATHENA
MSRP: $71.95Now: $65.00Was: $71.95Specifically 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...09343173- SKU:
- 09343173
- Availability:
- Ships Same Business Day
- Weight:
- 0.23 LBS
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- GASKET KIT
- RIDING STYLE:
- OFF-ROAD
- TYPE:
- TOP END
- UNITS:
- KIT
MSRP: $71.95Now: $65.00Was: $71.95 -
On Sale
ATHENA Piston Kit S4F06600002A
ATHENA
MSRP: $109.95Now: $99.00Was: $109.95Two-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...09100450- SKU:
- 09100450
- Availability:
- Ships Same Business Day
- Weight:
- 0.62 LBS
- DISPLACEMENT:
- 198 CC
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- PISTON HEAD SHAPE:
- FLAT TOP
- BORE SIZE METRIC:
- 65.94 MM
- COMPRESSION RATIO IMPERIAL:
- STOCK
- PRODUCT NAME:
- PISTON KIT
- TYPE:
- A
- UNITS:
- KIT
MSRP: $109.95Now: $99.00Was: $109.95Qty in Cart: 0Quantity:Price:MSRP: $109.95Now: $99.00Was: $109.95Subtotal: -
On Sale
ATHENA Piston Kit S4F06600002B
ATHENA
MSRP: $109.95Now: $99.00Was: $109.95Two-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...09100451- SKU:
- 09100451
- Availability:
- Ships Same Business Day
- Weight:
- 0.62 LBS
- BORE SIZE METRIC:
- 65.95 MM
- COMPRESSION RATIO IMPERIAL:
- STOCK
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- UNITS:
- KIT
- PRODUCT NAME:
- PISTON KIT
- DISPLACEMENT:
- 198 CC
- PISTON HEAD SHAPE:
- FLAT TOP
- TYPE:
- B
MSRP: $109.95Now: $99.00Was: $109.95Qty in Cart: 0Quantity:Price:MSRP: $109.95Now: $99.00Was: $109.95Subtotal: -
On Sale
ATHENA Piston Kit S4F090000050
ATHENA
MSRP: $273.95Now: $247.00Was: $273.95Two-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...09102764- SKU:
- 09102764
- Availability:
- Ships Same Business Day
- Weight:
- 0.93 LBS
- TYPE:
- REPLACEMENT FORGED PISTON
- PISTON DIAMETER METRIC:
- 89.96 MM
- PISTON MATERIAL:
- FORGED 2618 ALUMINUM
- BORE SIZE METRIC:
- 89.96 MM
- COMPRESSION RATIO IMPERIAL:
- 13.5:1
- ENGINE TYPE:
- 4-STROKE
- PRODUCT NAME:
- PISTON
- UNITS:
- KIT
- RIDING STYLE:
- OFF-ROAD
MSRP: $273.95Now: $247.00Was: $273.95Qty in Cart: 0Quantity:Price:MSRP: $273.95Now: $247.00Was: $273.95Subtotal: -
On Sale
ATHENA Piston Kit S4F07200006A
ATHENA
MSRP: $259.95Now: $234.00Was: $259.95Includes rings, clips and pin, Easy-to-follow step-by-step installation instructions09102666- SKU:
- 09102666
- Availability:
- Ships Same Business Day
- Weight:
- 0.96 LBS
- ENGINE TYPE:
- 2-STROKE
- PRODUCT NAME:
- PISTON
- UNITS:
- EACH
- COMPRESSION RATIO IMPERIAL:
- 16.0:1
- PISTON SIZE METRIC:
- STANDARD SIZE A
- PISTON DIAMETER METRIC:
- 71.95 MM
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- BIG BORE
MSRP: $259.95Now: $234.00Was: $259.95Qty in Cart: 0Quantity:Price:MSRP: $259.95Now: $234.00Was: $259.95Subtotal: -
On Sale
ATHENA Piston Kit S4F07200006B
ATHENA
MSRP: $228.95Now: $206.00Was: $228.95Includes rings, clips and pin, Easy-to-follow step-by-step installation instructions09102667- SKU:
- 09102667
- Availability:
- Ships Same Business Day
- Weight:
- 0.95 LBS
- ENGINE TYPE:
- 2-STROKE
- PISTON SIZE METRIC:
- STANDARD SIZE B
- PRODUCT NAME:
- PISTON
- UNITS:
- EACH
- RIDING STYLE:
- OFF-ROAD
- STYLE:
- BIG BORE
- COMPRESSION RATIO IMPERIAL:
- 16.0:1
- PISTON DIAMETER METRIC:
- 71.96 MM
MSRP: $228.95Now: $206.00Was: $228.95Qty in Cart: 0Quantity:Price:MSRP: $228.95Now: $206.00Was: $228.95Subtotal: -
On Sale
ATHENA Piston Kit S4F05400017B
ATHENA
MSRP: $130.95Now: $118.00Was: $130.95Two-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...09103892- SKU:
- 09103892
- Availability:
- Ships Same Business Day
- Weight:
- 0.55 LBS
- DISPLACEMENT:
- 124 CC
- ENGINE TYPE:
- 2-STROKE
- PISTON MATERIAL:
- 4032 ALUMINUM ALLOY
- RIDING STYLE:
- OFF-ROAD
- PISTON HEAD SHAPE:
- FLAT TOP
- UNITS:
- KIT
- BORE SIZE METRIC:
- 53.96 MM
- COMPRESSION RATIO IMPERIAL:
- STOCK
- PRODUCT NAME:
- PISTON KIT
- TYPE:
- B
MSRP: $130.95Now: $118.00Was: $130.95Qty in Cart: 0Quantity:Price:MSRP: $130.95Now: $118.00Was: $130.95Subtotal:
