BBR Tuning Racing Series Stage 4 66/80cc 2-Stroke Engine Kit

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FREE SHIPPING to Continental US
FREE 6-Month Warranty

Engine Color: Silver
Exhaust: Expansion Chamber - Chrome
Sale price $220.46 Regular price $244.95


When you’re in need of an engine with some serious power, the BBR Tuning Stage 4 Performance Engine Kit is the engine kit for you. With this performance package, you’ll get everything you need to get tons of power, from top-end speed to bottom-end torque. Outfitted with an Expansion Chamber for a smooth ride, and NGK spark plug and a high-performance head for major compression, and a high-performance carburetor for optimum speed, you’ve got a motor that’s ready to perform and more importantly, a motor that’ll last.

Compression of a Performance Motor with the Carburetor to Back it Up

With the BBR Tuning High-Performance head leading the way, this engine will give you more compression than ever. More compression means an increase in speed and pulling power, so not only will you go faster but those hills and inclines won’t give you a problem anymore. And if that wasn’t good enough, its tall heat syncs let your engine cool faster, letting your ride longer than ever.

Add to that the High-Performance Carburetor, and you’ve got yourself a speed machine. Its bigger jets will give your engine more fuel, and its air filter will let your carburetor breathe better than ever. You’ll definitely need a performance carburetor if you’re looking to run a high-performance head, and we made sure that this BBR Tuning package had that standard.

The Smoothest Running Engine You’ve Ever Felt

With an Expansion Chamber on this motor you can count on a smooth ride. Ever wonder why it feels so rough when you ride? That’s partially because the stock muffler restricts airflow coming out of your engine, and if you’re using performance parts you’ll need something that won’t limit your motor from expelling all that exhaust it creates.

Enter the Expansion Chamber. With no baffle in the chamber, there’s nothing limiting airflow except at the exhaust port. However, the banana shape of this muffler helps circulate air around the chamber so that instead of a large amount of smoke trying to go through a small hole, there’s a smooth flow of air coming from the chamber itself. Not only will you get a little bit of torque of this muffler, but you’ll also get a smoother ride, too.

PLEASE NOTE: Top end assembly required for this engine kit.

Product Details

The BBR Tuning 66/80cc bike engine kit is about 8.5" height 7" length 5" width. The bike engine kit fits on standard, male frames with tubing of 25mm to 29mm in diameter. Larger frame sizes require drilling into the bike frame with a stationary bolt and use the universal face plate to mount the front of the engine.

2.75+ HP (horsepower)

25 to 40 mph depending on the gear ratio and weight

Fuel Economy: 100-125 miles per gallon

Product Requirements

Installation is a breeze! The rider only needs some basic hardware skills, tools, and around 2-3 hours for installation and fine-tuning adjustments (Note: Seller is not responsible for misuse or this kit or any warranty after installation).

Fits Most 26" Wheeled Bikes (Mountain, Cruiser, Chopper, Road) with V-frame. The frame should have 9-11” of clearance between the bottom bracket and top bar, and the diameter of the frame tubes should be 25-29mm (around a 1”).

Complete Digital Installation Guide

Each BBR Tuning bicycle engine kit comes with a digital installation guide that takes you step by step through installing, adjusting, and fueling your brand new engine kit for the ride of your life.

Package Includes:


  1. Silver BBR Tuning 66/80cc 2-Stroke Engine
  2. Bonus- BBR Tuning Billet Aluminum High-Performance Cylinder Head 66/80cc
  3. Bonus - 66/80cc High-Performance Carburetor
  4. Bonus – Expansion Chamber, Expansion Chamber with Muffler, or High Performance Expansion Chamber
  5. Bonus - NGK B5HS Spark Plug
  6. Complete Clutch Cable Assembly with Clutch Wire Clip
  7. Drive Chain Idler Pulley
  8. Top Quality Japanese 202 Main Bearings
  9. 415 Bike Engine Drive Chain
  10. Drive Chain Guard
  11. 2-Stroke Spark Plug
  12. Locking Alloy Clutch Lever
  13. Upgraded Twist Throttle and Cable With Grip
  14. Updated 1.5L Black Teardrop Gas Tank (approx. Γàû of a gallon)
  15. Fuel Line
  16. Throttle Cable
  17. Gasoline Tank Switch
  18. Sprocket Clamp Assembly
  19. 44 Tooth Chrome Drive Sprocket with 9 Holes
  20. Large Spring (Heat Shield Spring)
  21. Extension Spring (Recoil Spring)
  22. High-Quality Japanese Bearings on Both Ends of Crank
  23. Required Hardware and Gaskets
  24. Magneto
  25. Kill Switch
  26. Complete Digital Installation Guide
  27. Spark Plug Removal Tool (While Supplies Last)!
  28. Standard Universal Mounting Bracket

On top of our strict quality assurance measures, we also back our engines with an industry-leading 6-month warranty

Disclaimer: Operating a motorized bicycle and/or bicycle engine kit carries a risk of serious bodily injury. The rider accepts responsibility for any and all vehicle operation that may lead to personal injury, economic loss, social distress, other losses, costs, and damages. is not responsible for injuries and/or damages resulting from operating this motorized bicycle or bicycle engine kit.

** Please note: Sprocket Clamp Assemblies included with BBR Tuning 2-Stroke 48cc and 66/80cc, and 4-Stroke 49cc bike engine kits come with only 1x set of metal plates. Older production of these assemblies included 2x sets, but from testing and redesigning, existing engine kits and engine kits in the future will only require 1x set. This redesigned assembly helps secure your rear wheel sprocket better than in the previous production.

Disclosure of accurate engine size: While we have chosen to use the long-standing factory branding engine size of "80cc", the true displacement of the bicycle engine is 66cc. Down through the years, China bicycle engine manufactures have advertised their biggest engine as 80cc, therefore we have listed them in the same way on our website. However, the bore and stroke of an 80cc being 47x38mm equal 66cc. Therefore the true displacement of the 80cc bike motor is 66cc. In the west, the volume of a cylinder is calculated by using the formula Volume = Pi x Radius Squared x Stroke. However, in the east, the displacement of an engine includes the area of the cylinder head's combustion chamber as well as the volume of the cylinder. Therein lies a discrepancy between measuring standards by the manufactures in China with those in the United States. However, all "80cc" engine kits on the market today are actually 66cc in displacement size if measuring by US standards.

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Customer Reviews

Based on 104 reviews

Waiting for the rain to stop so I can do some riding through the back roads

Anthony Migliaccio
What an improvement over my China doll !!!!0

At first I was struggling with the price. I am glad I made the purchase tho. Man does this thing haul. Especially after I put on a reed valve kit. I am loving this thing. Still in break in but it is worlds better than my old China. 🤙🤙🤙🤙🤙


Works great

Aaron Wieler
Best quality EVER!

I bought this engine kit so that I would have a quick way to get around the yard (We have a big yard), and it has served me well! Although it is not as fuel efficient as they say, it is still a GREAT machine! Would recommend it to everyone.

Daniel Miller

Fun little kit. Had to attach the piston to the con rod and bolt down the jug and head. No big deal but could be intimidating to someone who hasnt done it before. All the parts fit. Started on the first try. The clutch was a little rattley at first but quieted down as I broke it in. I was just expecting enough power for an "assisted" pedal power but it will accellerate my 240lb ass uphill. Burns clean and is quieter than I expected. I see problems with the chain tensioner as mileage increases so will probably upgrade that. Chain is good quality and seems like it wont stretch much.

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