The NR200 Is Back as the SEMTO ST-FL2: What's New in the 8.6cc Water-Cooled 2-Cylinder Engine
If you owned an NR200, you'll recognize the SEMTO ST-FL2 straight away. That's because it's the NR200's successor, rebuilt around years of owner feedback.
SEMTO restarted the NR200 project and, together with Stirlingkit, kept the 8.6cc water-cooled layout builders already trust, then improved the parts that mattered most: more power, better-lubricated connecting rods, a built-in belt tensioner and a kit you build yourself.
In this article, we'll walk you through why the engine came back, what stayed the same, what changed and why, how it compares with the NR200 and the Toyan FS-L200AC, and whether it's the right engine for you.
Why SEMTO Brought It Back
The NR200 was never just another engine on our shelves. You put it in RC cars and boats, bolted it to test benches, and gave it turbochargers, clutches and custom exhausts. Then production stopped in 2024, and there was simply nothing else like it: a compact 8.6cc water-cooled twin-cylinder engine that fits a 1/8-scale build.
SEMTO felt the same way. SEMTO invested to restart the project, and together we decided not to just reissue the old engine. If we were bringing it back, it had to be better.
Backed by SEMTO
SEMTO invested in new production and development to give this engine a second life.
A layout you already trust
The same 8.6cc water-cooled twin-cylinder engine that you and many other builders have already run hard.
Shaped by your feedback
Your emails, reviews and questions over the years decided what we changed.
From NR200 to ST-FL2
Then and Now
NR200
The blue-and-silver original. Supplied fully assembled, nitro or gasoline.
SEMTO ST-FL2
The new green-and-black generation. A kit you build, upgraded where it counts.
The Good Details We Kept
If you've run an NR200, a lot of this will feel like home. We kept everything you liked:
- The same 8.6cc inline twin four-stroke layout, with an 18.0 mm bore and 17.0 mm stroke
- Water cooling, with the centrifugal water pump driven by the timing belt
- An overhead camshaft (SOHC) and a single carburetor, so there's still only one mixture to tune
- Push-button electric start through a belt-driven flywheel
- CNC-machined, anodized aluminum, sized for 1/8-scale RC projects
The Best of Both: Toyan FS-L200AC Meets NR200
The SEMTO ST-FL2 didn't come from a blank sheet. It brings together the best of two engines many of you already know: the red Toyan FS-L200AC (also sold as the SEMTO ST-NF2), loved for being easy to build and run, and the NR200, loved for its power and water cooling. Then it adds a few improvements neither of them had.
 Toyan FS-L200AC(SEMTO ST-NF2) |
 NR200 |
 SEMTO ST-FL2 |
|
|---|---|---|---|
| Build and setup | |||
| Build it yourself as a kit | ✓ | – | ✓ |
| Full assembly video and printed manual | ✓ | – | ✓ |
| Single carburetor, easy to tune | ✓ | ✓ | ✓ |
| Push-button electric start | ✓ | ✓ | ✓ |
| All-in-one 3-in-1 start, ignition and power module | Optional | – | ✓ |
| Matching starter kit | ✓ | ✓ | ✓ |
| Power and performance | |||
| Displacement | 7cc | 8.6cc | 8.6cc |
| Power | 0.6 PS | More than 1 PS | ✓ About 30% more than NR200 |
| Normal RPM range | Up to 16,000 | Up to 18,000 | ✓ Up to 20,000 |
| Higher compression | – | – | ✓ New |
| Cooling | |||
| Water cooling with built-in pump | – (air-cooled) | ✓ | ✓ |
| Radiator works without a fan | – | – (fan needed) | ✓ New |
| Reliability and maintenance | |||
| Hooked connecting rods for better lubrication | – | – | ✓ New |
| Two oil holes in each connecting rod | – | – | ✓ New |
| Easy-to-remove connecting rods | – | – | ✓ New |
| Built-in belt tensioner | – | – | ✓ New |
| Installation and RC use | |||
| Sized for 1/8-scale RC cars | – | ✓ | ✓ |
| Room for clutch and transmission | ✓ | ✓ | ✓ |
| Starter motor on either side | – | – | ✓ New |
| Two separate exhaust pipes | ✓ | – | ✓ |
Compared with the Toyan FS-L200AC, the SEMTO ST-FL2 gives you about twice the power, a higher RPM range, water cooling for steadier temperatures on longer runs and a size made for 1/8-scale RC cars, while keeping the build-it-yourself experience that made the FS-L200AC so popular.
Compared with the NR200, it keeps the 8.6cc power and water cooling, then makes life easier: one 3-in-1 module instead of separate parts, a radiator that works without a fan, connecting rods that are better lubricated and easier to service, a belt you can tension yourself and a starter motor you can mount on either side.
7 Upgrades, Straight from Your Feedback
Before restarting production, SEMTO and Stirlingkit went back through years of NR200 feedback: support emails, reviews and the questions you sent us mid-build. If something came up again and again, it went on the list. Here's what changed, and why.
Higher compression, about 30% more power
Higher cylinder pressure means stronger combustion on every stroke, so you get more power from the same 8.6cc.
You told us: "I'd love a bit more pull for heavier cars."
A higher normal RPM range
The ST-FL2 is rated for 3,000–20,000 rpm in normal running, up from 3,000–18,000 rpm on the NR200, and can still reach up to 22,000 rpm.
More usable speed, without pushing the engine to its limit.
Hooked connecting rods
A small hook on each connecting rod splashes oil from the fuel onto the crankshaft and bearings as the engine turns.
Better lubrication means less wear, run after run.
Two oil holes in each connecting rod
Oil now reaches both ends of the rod, right where the load is highest.
You told us connecting rods were a worry at high RPM. This is our answer.
Easy-to-remove connecting rods
You can now check or replace a connecting rod without taking the whole engine apart.
Remember stripping the whole engine just to look at one rod? Not anymore.
Starter motor on either side
Mount the starter motor on the left or the right, whichever suits your chassis.
Because no two RC builds are the same.
Built-in belt tensioner
If the timing belt loosens over time, a quick adjustment brings it back to the right tension.
You told us about belts slipping at high RPM. Now you can fix it in a couple of minutes.
Design Changes You Can See
Put the two side by side and you'll see the family resemblance. Up close, though, the SEMTO ST-FL2 has a look of its own:
| NR200 | SEMTO ST-FL2 | What it means for you | |
|---|---|---|---|
| Exhaust | One combined pipe | Two separate straight pipes | A look closer to a real car engine. |
| Valve cover | Flat cover with NR-200 logo | Finned cover with SEMTO ENGINE logo | A more detailed, mechanical look on top. |
| Color | Blue and silver | Green and black | A fresh look that sets the new generation apart. |
| Timing pulleys | Gold | Silver | Matches the new color scheme. |
| Starter motor | One fixed side | Left or right | Fit it to your chassis, not the other way round. |
| Belt tensioner | None | Built in | Keep the timing belt snug yourself. |
| Size and weight | approx. 105 × 100 × 95 mm, 800 g | approx. 113 × 92 × 103 mm, 900 g | A very similar footprint, slightly taller and about 100 g heavier. |
Now a Kit You Build Yourself
Your NR200 arrived ready-made. The SEMTO ST-FL2 arrives in pieces, and that was a deliberate choice.
When SEMTO launched its first twin-cylinder engine, the SEMTO ST-NF2, as a kit, builders told us the build was their favorite part. Putting the engine together themselves meant they understood it, trusted it and enjoyed it more every time it ran.
The NR200 left a different feeling. Because it came fully assembled, many owners never saw what was inside. When something needed attention, opening it up for the first time felt daunting, and some told us they wished they had built it themselves. That was one of the NR200's real regrets.
So this time, SEMTO and Stirlingkit decided to keep the green twin-cylinder engine as a kit. We think it gives you a better experience from day one:
- You'll know your engine inside out. Putting it together shows you exactly how the crankshaft, connecting rods, camshaft and valves work together.
- Maintenance gets less scary. Once you've built it, you know how it comes apart. Add the easy-to-remove connecting rods, and servicing it is no big deal.
- You won't be on your own. A full assembly video, a printed manual and a basic tool are included, so you can take it one step at a time.
- That first start hits differently. Hearing an engine you built yourself fire up for the first time is a feeling you won't forget.
NR200 vs SEMTO ST-FL2: Specs Side by Side
| NR200 | SEMTO ST-FL2 | What this means for you | |
|---|---|---|---|
| Status | Discontinued | Pre-order, ships mid-November 2026 | Order now to secure yours, with parts and support for years to come. |
| Displacement | 8.6cc (2 × 4.3cc) | 8.6cc (2 × 4.3cc) | Same size engine. |
| Bore × stroke | 18.0 × 17.0 mm | 18.0 × 17.0 mm | Same cylinder dimensions, so the power gain comes from the upgrades inside. |
| Power | More than 1 PS | About 30% more | Noticeably more pull, especially in heavier RC cars. |
| Normal RPM range | 3,000–18,000 rpm | 3,000–20,000 rpm | More usable speed in everyday running. |
| Max RPM | Up to 22,000 rpm | Up to 22,000 rpm | Same top speed. Keep full-speed runs short on both. |
| Connecting rods | Standard | Hooked, two oil holes, easy to remove | Better lubrication, less wear and much easier servicing. |
| Starter motor position | Fixed | Left or right | More freedom to fit the engine into your chassis. |
| Belt tensioner | No | Yes | A loose timing belt takes minutes to fix yourself. |
| Supplied as | Fully assembled | Kit, you build it | You learn how it works and find maintenance easier later. |
| Fuel | Nitro or gasoline | Nitro | Gasoline fans should look at the Toyan FS-L200AC / SEMTO ST-NF2 gasoline version. |
| Weight | approx. 800 g | approx. 900 g | About 100 g heavier, still sized for 1/8-scale cars. |
▲ marks an upgrade on the SEMTO ST-FL2. Rows without ▲ are the same on both engines, or simply different.
Watch the SEMTO ST-FL2
Turn the sound up. Here's the ST-FL2 firing up, followed by the full build from the first part to the first start.
So, Is It Worth It?
Here's our honest take:
- If you loved your NR200 and wished it had a little more power and was easier to look after, the ST-FL2 is exactly that engine.
- If you missed out on the NR200, this is your chance to get the same proven layout, now in its best version yet.
- If you only run gasoline, the ST-FL2 isn't for you, as it's nitro only. Take a look at the SEMTO ST-NF2 gasoline version instead.
Pre-Order Launch Offer
Now on pre-order. Expected to ship mid-November 2026.
Engine: use code E50 for $50 off. $399.99 → $349.99
Starter Kit: use code M2026 for 10% off. $109.99 → $98.99
First 10 orders: after delivery, we refund $20 on the engine plus half of what you paid for the Starter Kit, to your original payment method.
Pre-order launch offer for a limited time. Please check the product page for current details.
Already own an NR200? A few things for you
- A thank-you, from us: 2 free glow plugs. You helped make this engine better. When you order the SEMTO ST-FL2, just add your NR200 order number in the order note at checkout, or email it to us at service@stirlingkit.com after you order. Our team will add 2 spare F-type glow plugs to your parcel before it ships. That's a full spare set for both cylinders, so a worn plug never ends a running session.
- Your old parts won't fit. We'd rather tell you now: because the ST-FL2 has redesigned connecting rods and other changes, NR200 starter kits, spare parts and accessories won't fit it. Keep them for your NR200.
- Get the matching starter kit. To run the ST-FL2, you'll need the ST-FL2 Starter Kit, an 11.1V 3S LiPo battery (T-plug) and 25% nitro fuel.
- Clutch on the way. A dedicated SEMTO ST-FL2 clutch is in development. Tap "Notify Me" on the product page and we'll let you know when it's ready.
NR200 and SEMTO ST-FL2: Common Questions
Is the SEMTO ST-FL2 the same engine as the NR200?
Close, but not quite. The SEMTO ST-FL2 is the NR200's next generation. It keeps the same 8.6cc water-cooled inline twin layout, bore and stroke, and adds higher compression, about 30% more power, a higher normal RPM range, redesigned connecting rods, a starter motor that can go on either side and a built-in belt tensioner.
Why did SEMTO bring back the NR200 as the SEMTO ST-FL2?
Because builders loved it, and once it was gone there was nothing quite like it. SEMTO invested to restart the project, and together with Stirlingkit went through years of NR200 customer feedback. The result keeps the layout you know and improves power, lubrication, maintenance and belt tension.
Is the NR200 still available?
No, the NR200 has been discontinued. The SEMTO ST-FL2 is its upgraded successor.
Do NR200 parts fit the SEMTO ST-FL2?
Unfortunately not. The SEMTO ST-FL2 and NR200 use different parts, so starter kits, spare parts and accessories don't swap between them. If you're unsure about a specific part, email us at service@stirlingkit.com before ordering and we'll check for you.
Does the SEMTO ST-FL2 come assembled like the NR200?
No. The NR200 came fully assembled, while the SEMTO ST-FL2 is a kit you build yourself. Don't worry if you've never built an engine: the full assembly video and printed manual walk you through every step.
Is there a gasoline version of the SEMTO ST-FL2?
No, the SEMTO ST-FL2 is a nitro engine that runs on 25% nitro fuel. If you prefer gasoline, the SEMTO ST-NF2 comes in a gasoline version.
Thinking about moving from your NR200 to the SEMTO ST-FL2, or just have a question? Drop us a line at service@stirlingkit.com. We'd love to hear from you.
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