79cc Monster 90 Bike Engine Kit – Complete 4-Stroke Kit


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SKU: 4EK-001 Categories: ,




This monster is upgraded to make the overall size smaller. A Large 79cc engine with a CNC single speed transmission featuring a  ⅝ shaft keyed centrifugal clutch. Replacing the on motor gas tank with a standard 2.0 lier frame mount tank. Also included is an upgraded exhaust adapter and chrome exhaust pipe, with this setup all 2 stroke pipes can be bolted up.

4 Stroke engine kits are very different from 2 stroke kits in many ways. Building a 4 stroke bike is a little more involved then the two strokes, the extra effort is worth it. Pull start engine, not push start like the 2 strokes. Overall this type of engine is more reliable with more power and torque. With some of the larger cc motors, the top speeds far exceed the 2 strokes. Since these motors are larger in cc they are also larger in size and weight. Almost all bicycles will need to use a wider crank setup to clear the motor, the stock arms and pedals will hit the motor when pedaled as a regular bike. One piece cranks will also require a bottom bracket conversion set as well (not included).

This style of the engine might need slight modification to the bikes and will not fit all frames. 

Advantages of 4 Stroke Bicycle engine kits:

  • Use straight gas (no mixing oil with gas)
  • More Horsepower
  • More Torque
  • Quieter Engine

This complete kit includes:

  • 78.5cc – 79cc 3HP OHV GasBike Horizontal Shaft Gas Engine
  • Transmission for 78.5cc – 79cc OHV GasBike Horizontal Shaft Engines
  • Heavy Duty Bicycle Mounting Kit for 78.5cc – 79cc or 212cc OHV Predator Horizontal Shaft Engines
  • 79cc Muffler with Adapter – Chrome
  • 2.0L Gas Tank
  • Tank Switch
  • Fuel Filter
  • Fuel Line #2
  • Transmission Cover
  • Throttle Handle
  • Throttle Cable – 50″
  • 44 Tooth Sprocket
  • Pineapple Bushing Kit
  • 415 Heavy Duty Chain
  • Idler Pullet Chain Tensioner with 2 Bolts
  • Throttle Linkage

The construction and engineering on this unit have been upgraded for improved durability and service life. This tough gas engine features a durable cast iron cylinder that withstands wear and abuse, fuel shut off for safe transport and gas-saving overhead valves for a cooler, cleaner performance. The horizontal shaft design makes this an ideal all-purpose gas engine.

  • Upgraded engineering and construction for improved lifespan
  • Durable cast iron cylinder withstands wear and abuse
  • User-friendly controls for easy starting and operation
  • Fuel shut off for safe transport
  • Ball bearing support shaft for long life
  • Recoil start


  • Engine displacement: 78.5cc – 79cc
  • Horsepower: 3 HP
  • Maximum speed: 3600 RPM
  • Maximum Torque: 3.5 ft. lbs. @ 2500 RPM
  • Mounting pattern: 102mm L x 104mm W – 61.5mm W (4 in. L x 4.9 in. W – 2.4 in. W )
  • Mounting type: Horizontal
  • Shaft rotation direction: Counterclockwise
  • Sound rating: 104 dB
  • Start type: Recoil start
  • Product Height: 8.5 in.
  • Product Length: 12-1/4 in.
  • Product Weight: 24.25 lbs / 11 kg
  • Product Width: 11-1/2 in.
  • Shaft length: 2.4 in. (60.1mm)
  • Shipping Weight: 26 lbs
  • Stroke length: 37 mm


  • 79cc Transmission plate with complete sprocket and shaft assembly (Sprocket = 22T and 9T)
  • 11 tooth, #415 sprocket Centrifugal Clutch
  • Complete hardware for mounting the transmission plate on the engine (Screw thread size is 5/16-24)
  • #415 Chain, 41 Link with a master link

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.