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Thunder Shark Pro Racing 66cc/80cc Bicycle Engine Kit - 5.0 HP

  • $ 38900
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NOTE: Top end assembly required for this engine kit.

How to Install The Top End of a 80cc 66cc 48cc 2-Stroke Bicycle Engine Kit


This kit is for the serious racer. With almost every upgrade from the cylinder up, it does require assembly.

Convert your bicycle to a motorized bicycle by adding a 2 stroke engine kit to it. The kit fits best on bikes with 25 to 30mm diameter front down tube and 70 degree Vee type frame like a mountain bike but can be installed on larger diameter tube frames with modifications. “Looks Cool” on the older beach cruiser type coaster brake bikes. The motor bolts to the bicycle frame in the center of the frame (additional mounting options available). A second Heavy Duty chain is attached from the motor to the rear wheel via a second sprocket attached to the rear wheel.


2 stroke motor kits are started by “bump” starting them. While holding in the clutch, pedal the bike quickly. When you release the clutch after the bike gets to speed, it push starts the motor.

The kit will average around 25-35 M.P.H depending on rider weight and rear sprocket gear ratio.

Gas Mixture

This bike motor kit comes with everything that you'll need except gas and oil since this is a 2 stroke, 2 stroke oil needs to be added to the fuel. Always mix gas in a gas can, not the gas tank. When the engine is new, it would need to be broken in with a richer mixture, after at least 1 tank of gas, then the mix can be “leaned out” (less oil). Never go less than 32:1 ratio (4oz of oil per Gallon).

  • New Motor - 16:1 (8 oz of oil per gallon)
  • After Broken in - 32:1 (4 oz of oil per gallon)

You will be able to stop or start the engine as you ride. This kit gets maximum fuel efficiency stock at around 100 miles per gallon.

The Motor will require some assembly, the top end of the motor must be installed.

5.0 HP Engine Kit Includes: 

  1. Thunder Shark Pro Racing 66cc/80cc Bicycle Engine - 5.0 HP
  2. Dio Reed Valve Zeda Racing Cylinder and Carburetor Assembly
  3. Shark Racing CNC Cylinder Head - High Performance
  4. CNC High Sprocket Assembly - High Performance
  5. CNC Universal Mount - High Performance
  6. Boost Expansion Chamber Muffler - High Performance
  7. Supercharge CDI - High Performance
  8. Spring Chain Tensioner - High Performance
  9. Stainless Steel Heavy Duty 66cc / 80cc Engine Screw Set
  10. Friction Clutch, Pedal Start
  11. Magneto With Solid State New Design Capacitive Discharge (CD) Ignition
  12. 2 Cycle air cooled gas / oil mix engine.
  13. 2.0 Liter/0.66 Gallon Fuel Tank, Tear Drop Shape (Black Color)
  14. Push Button Clutch Lever And Cable
  15. Twist Throttle With Engine Kill Switch
  16. Fuel Line
  17. Improved Gas Valve
  18. Drive Chain Idler
  19. Improved NT Carburetor
  20. Chrome Lined Cylinder Wall
  21. Head With Center Fire Spark Plug
  22. 202 Crankcase Bearings
  23. Needle Bearings On Piston Wrist Pin
  24. 415 Heavy Duty Chain
  25. Chain Guard
  26. Steel Tube Intake
  27. Fuel Filter
  28. Pulling Tool Kit
  29. Universal Motor Mount
  30. All The Mounting Brackets, Gaskets, And Hardware Including Nylon Locking Nuts
  31. 6-Month Limited Warranty Included - FREE
  32. Free technical support within one (1) week after receiving the kit

How to Install 80cc 66cc 48cc 2-Stroke Bicycle Engine Kit

 Orders received Monday - Friday by 3:00PM EST are eligible for 
Same Day Shipping! Except for USPS which ships the next business day.

Same Day Shipping Available 

Gas And Oil Mixture For Fuel Ratio: (Use of a synthetic 2 stroke oil is recommended.)

This bicycle motor engine kit is a 2 cycle/2 stroke design, therefore, a gasoline/oil mixture is necessary as follows:
  • When New: 16 to 1 (8oz per Gallon)
  • After 2 Tanks Of Break In: 32 to 1 (4oz per Gallon)
The engine crankshaft bearings are lubricated from the oil in the gas mix. A rich break in oil mixture ensures bearings will not cease during engine break in period.

Our gasoline operated products are NOT compliant with Environmental Protection Agency ( E.P.A. ) or California Air Resources Board (C.A.R.B) for the use on/off Public roads. Upon purchase, the buyer agrees to use products for racing (closed-course competition) only and NOT for on/off public roads.


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If you need help with installation or troubleshooting, kindly use our Builder Locator to find builders near you. Builders are experts with motorized bicycles.

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