Zeda Bicycle Engine Showdown: 80cc vs 100cc vs 85cc – Which One Fits Your Build?
Dec 11th 2025
If you’re looking at Zeda bicycle engines for your next motorized bike build, you’ve probably seen debates about which size is “the best.” The truth? They’re all great engines—it just depends on your riding style and what kind of performance you want.
Whether you’re brand-new to motorized bikes or you’ve already got a few builds under your belt, understanding the difference between the Firestorm Series Zeda 80, Zeda 100, and Zeda 85 will help you pick the right match for your ride.
Understanding the Lingo
Lets define a couple terms to help you understand all the details:
Engine Stroke: The distance travelled by one complete movement of the piston inside the engine cylinder—either up or down.
Cylinder Bore: The bore is the diameter of the hole in the engine cylinder. This directly corresponds to the size of the piston which is just a tiny bit smaller to allow it to move freely inside the cylinder.
First Things First – What’s With the “/” in 66cc/80cc or 80cc/100cc?
You’ve probably noticed labels like 66cc/80cc or 80cc/100cc and wondered what’s up with the slash. Here’s the deal:
- In the U.S., engine size is measured by bore and stroke (the true displacement inside the cylinder).
- In other countries, the measurement is often rounded up or based on estimated volume.
So, what we call an 80cc might technically measure around 66cc here in the States, but that doesn’t change how well it performs. For the full rundown let’s take a look at each Firestorm bike engine kit.
Firestorm Zeda 80 – The Classic Favorite
47mm bore | Lightweight & quick | Huge aftermarket support
The Zeda 80 is the engine that started it all. It’s quick-revving, reliable, and easy to work with, making it a favorite for first-time builders and seasoned riders alike.
- Perfect for daily rides, commuting, or experimenting with mods.
- Tons of aftermarket parts and tutorials available.
- Lightweight build keeps it fun and responsive.
Why choose it: If you want a snappy, dependable engine that’s easy to customize and grow with, the Zeda 80 is always a solid choice.
Zeda 100 – Torque and Versatility
50mm bore | More low-end power | Still rev-happy
The Zeda 100 takes everything riders love about the 80 and adds more torque and climbing power. It’s built for heavier riders, bigger bikes, and anyone who wants that extra muscle.
Available in two versions:
Zeda 100 Firestorm
Classic one-piece head/cylinder design for better cooling, strong and reliable.
Zeda 100 Firestorm MAX
Two-piece head and cylinder allows for easy access and customization.
Pair either model with the ZDX65 expansion chamber and you’ll unleash a whole new level of performance.
Why choose it: If you want stronger uphill pull, more torque, and the ability to handle bigger builds, the Zeda 100 is the way to go.
Zeda 85 – Race-Ready Power
52mm bore | Race-inspired ports | Performance-focused
Unlike engines that just bump displacement numbers, the Zeda 85 is a true 85cc design with racing DNA baked in.
- 52mm bore delivers serious low-end power.
- Redesigned ports maximize top-end speed.
- Upgradable head lets you push performance even further.
- Note: This one doesn’t pair with the ZDX exhaust, but it has plenty of output on its own.
Why choose it: If you want a motorized bike that feels more like a race machine, the Zeda 85 is built for raw performance.
Which Zeda Engine Is Right for You?
At the end of the day, it’s all about matching the engine to your style:
| Engine | Best For | Bore/Pistion Size | Key Notes |
|---|---|---|---|
| Zeda 80 | Beginners, modders, everyday riders | 47mm | Lightweight, quick-revving, huge aftermarket |
| Zeda 100 | Heavy riders, hills, power seekers | 50mm | Extra torque, Firestorm & Firestorm MAX options |
| Zeda 85 | Speed chasers, custom builds | 52m | Race-insipired design, upgradable head |
Final Thoughts
Zeda Firestorm series bicycle engine kits offer something for every kind of rider. Whichever bike engine you choose, you’re getting a motor that’s built to perform—and built to thrill.
Need help figuring out which one fits your setup best? Reach out to our team. We’re riders too, and we’ll help you get the right engine on the right bike.