• $599.99
    Unit price per 

In Order to Purchase this upgrade you will first need to purchase one of our 150cc engines first.  You can then add this upgrade to that engine.

Convert your new 150cc GY6 engine into a 184cc racing engine
This listing is an upgrade to a 150cc engine that you are already purchasing. This upgrade can be installed on any of our GY6 150cc engines that we sell. If you are purchasing a 150cc GY6 engine we can install a 62mm big bore kit increasing your piston and cylinder size from 54.5mm to 62mm, adding an additional estimated 10% horsepower and a 60.8 stroker. See the difference with the GIF below. We also will upgrade your transmission installing the stage 1 and 2 transmission system with a high stall clutch and a performance variator, giving you a full high performance transmission system.




Stock GY6


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The clip above shows hill climbing ability of our flagship 184cc GY6 engine (stroked, big bore, and high compression). (This is the SAME engine being sold in this listing) The purpose of this comparison is to showcase our ability to radically (and reliably) improve the performance of the GY6 engine.

We start with your base new engine, disassemble, bore out your case, and install the larger more powerful 62 mm big bore piston and cylinder and the 60.3mm stroker crankshaft. We then fully reassemble and fully test your new engine before shipping to you.


Racing Engine
Our Buggy Depot 175 and 184cc performance engines are for off-road racing purposes only.


Engine BDX 184cc GY6
Displacement 183.56cc
Bore x Stroke 62mm x 60.8mm
Compression 10.35:1
Redline 9,000RPM
Use fuel Premium 93 Octane
Charging 100w 8-pole Upgrade



Our 184cc BRUTE MUSCLE upgrade is a massive improvement over what you're used to getting out of your old 150cc engine. Tires will spin and dirt will fly around the trail or track, even with the most aggressive tires. Want to know how it works on the inside? Read our very detailed article on the advantages of big bore and stroker builds.



This ain't an eBay kit we're throwing on your engine. This is one of OUR secret recipe builds - A BDX EXCLUSIVE. We've blown up a bunch of test engines over the years getting to this level of power for price. And have modified and tweaked components with our own in-house equipment, machinery, and ingenuity to balance power with reliability. Unlike others, this setup will last you MORE than just a couple season. When taken care of with proper filtration and lubrication, you can expect our builds to last as long or longer than stock. This build is rock solid on reliability and BACKED UP WITH OUR 1YR WARRANTY.

See that BDX 184 kicking dirt going up the hill in the video?
That 184 engine was built in 2012 and still starts on the first crank. No smoke, no oil, no nothin'.

The expensive lessons in GY6 design that we've learned at BD are what make the difference in power and reliability between our builds and other options. Other places aren't even confident enough in their own skills to provide a warranty AT ALL on their builds.

Think about it. Don't pay for someone else's Science Fair project. Or pay hundreds extra for a middleman's sticker. We machine our exclusive top-level parts HERE IN VIRGINIA, USA and offer them to you directly.

We know you can buy lesser parts elsewhere and do it yourself, but by the time you've blown it once or twice is it really worth it? And there's no way you're going to get anywhere near the power density per CC that you get from the BRUTE package.

Skip all of that hassle - Go BDX.

Premium USA Boring and Machining

Our borework is done on 4,500 pound machinery built for precision. The end result is a center bore far better than stock. We hold a tight consistent tolerance to the outer wall of the 62mm cylinder sleeve. This contributes significantly to long-term reliability and cannot be achieved with 5 pound handheld drill boreout tools the other guys are using.

Custom BDX 184cc piston. Machined in-house, Engineered in-house.

This isn't a random piston thrown into the build from whatever popular brand. We specifically engineered and tailored this piston to this exact build combination.

Critical parameters like squish band, deck height, compression ratio, ring landing thickness, all dramatically change the performance and reliability characteristics of your engine. Our specs are all calculated, known and nailed down. Ask other sellers if they even know what these terms mean!

Go ahead, we'll wait with our engineering toolkit open to check whatever fuzzy numbers they come back with!

Our perimeter dome matches the angle and contour of the cylinder head, with a tight deck height and a small squish band.

The dish of the piston is tuned to hit our target high-compression ratio of 10.35:1. We wanted you to be able to run pump gas reliably without spark knock issues. For reference, stock is 9.2:1. Generally speaking, the higher this number is, the bigger bang and power you get out of the same size CC. So no, due to this and many other factors, not all 184cc builds are created equal!


You won't find the same thing coming out of China, Taiwan, or anywhere else in the States. Our engine packages are exclusively available here at Buggy Depot.

We carry our own brand. Others can't do the math and don't understand the underlying design principles. If you see a builder riding the coat tails of overseas companies and throwing a bunch of brand names in your face to sell their work, watch your wallet! We cut out the middle man and provide badass purpose-driven builds for far less.


Every BDX build begins by doing the math right from the very start. Firmly understanding how turn the optimal numbers into physical parts, we use these calculations to inform and direct development of the final pieces. This allows us get bigger and more dependable results for a smaller asking price.



1. How many times can you afford to rebuild in order to get it right? or "right enough"
2. How much downtime will you have sending your engine back and forth to your "builder"?

Think you can avoid hassle by using a "no machining" big bore kit?


We've been there and done all of that, and have paid for our share of R&D so you don't have to.

Do it right the first time!

Variator BDX S2 115mm Variator
Clutch BDX S2 Clutch
CVT Action Sliders x S1 Spring
Crankcase Oil 800ml 10w40
Gear Oil 125ml 80w90
This is a HIGH COMPRESSION engine, so you'll want to learn how to start the engine correctly. No special starters or batteries are needed.

When starting cold, if the crank slows down on the compression stroke, simply "bump" the key. Turn the key back to "Run", then forward to "Start" within about 1/2 second. This will bump the piston past the compression stroke and keep the crankshaft moving. This will ease with breakin.
Use a genuine UNI FILTER only. No K&N filters, No cheap Chinese foam filters. Absolutely no stock filters.
Break-in information is in our 184cc manual. Download it here.

Adjusting valve lash is not required and not recommended during or after break-in.
Please note: We will also install other performance parts not listed here if you purchase them from us at the same time as this service.

Every BDX Speed Shop engine build is covered under warranty.

Other "builders" try to slide out from under their own work and avoid warranty by telling you "race engines" aren't covered. That's some BS.

BDX 12-Month/2,000 Mile Limited Parts Warranty

The new components of your engine are warrantied for 1 year (365 days) from the date of delivery or 2,000 miles, whichever condition is met first. The warranty covers issues with the parts that arise due to defects in material or factory workmanship.

Conditions and exclusions:

IMPORTANT! You must use a genuine UNI Air Filter as a condition of this warranty.

-If the engine is run for any period of time without an air filter, the warranty will be terminated.
-If the engine is run for any period of time without proper lubrication, the warranty will be terminated.
-Belts, CVT weights, and clutches are not covered under warranty.

Buggy Depot does not accept returns or refunds on engine builds under any circumstances.

Question: Can I modify my engine without voiding the warranty?
No. Each component was chosen to match with other parts of the build. Changing parts of this build will most likely reduce performance, or cause damage. If you're going to do it anyway and sacrifice your warranty, contact us before modifying the engine for advice.

Warranty Procedure
If you think a component should be covered under warranty, please contact us online and submit a warranty request.

IMPORTANT! Buggy Depot does not operate through 3rd party repair shops, thus under no circumstance shall Buggy Depot be liable for service costs by any 3rd party shop or service provider.


Issues are going to happen anywhere.
Read what people say about us.

"The short version of my story is that my 1 year old upgraded performance engine with less than 10 hours of use began to have serious oil leak issues... I reached out to BD and eventually connected with Travis to explain my dilemma via e-mail as that is the approach. I halfway expected the reply to be "we are really sorry but your engine is beyond the warranty period, so best of luck to you". Instead, Travis and I had a real discussion about some of the issues my engine was having... he agreed to pay for the entire cost of shipping and repairing my GY6 engine...

I just want to let others know that contacting BD via the methods defined on the website certainly does work and that you will get the help you have come to expect from the folks at BD. ... be calm and patient as the folks at BD work to make things right so they can continue to be a valued business to all of us. Well Done BD and Travis!!"

- William J. (175cc Engine Build) Read the full review

William's engine was 10-months past a 2-month warranty. However, it was clear that the original error was on our end. If you have a legitimate problem, we'll make the situation right. When others would give excuses and hang you on technicalities.





Read our article on how displacement relates to more power.
How big bore kits & strokers work




Don't be tricked by "200cc" and "180cc" engines on the internet that are actually 171cc. Our engine uses a high quality 62mm piston for exactly 174.5cc actual displacement.




Arrives with Large Valves Installed
The large 27mm/24mm valves allow the engine to breathe better at high RPM, allowing for higher top speeds. This is a very noticeable improvement if your original engine came with the smaller 24/23 valves.