Out of the box, KTM’s 4-stroke enduro models (and their Husky and GasGas cousins) look the part — but once you start riding, it’s obvious:
They’re corked up, restricted, and way too polite.
Lean fuel maps, heavy engine braking, sluggish throttle — it’s like the bike’s begging to be let loose.
That’s where Two Stroke Performance’s (TSP) new ERM (ECU Reflash Module) comes in.
If you want that instant throttle hit, smoother decel, and real usable power, keep reading. This is the Four Stroke Performance upgrade your 350 or 500 has been dying for.
What’s Wrong With Stock?
KTM’s stock ECU settings are built to meet emissions regs, not rider expectations. That means:
- Lean fuel mapping = Boggy throttle and soft bottom end.
- Aggressive engine braking = Jerky slowdowns, harder to carry flow in the woods.
- Throttle snatch = Rough on/off transitions that kill confidence in technical stuff.
- Timing neutered for emissions = Power left sitting on the table.
If you’ve ever twisted the throttle in 2nd gear and thought, “Where’s the hit?” — this is why.
What the TSP ERM Does (And Why It Matters)
The TSP ERM isn’t just another “plug it in and hope” tuner.
It reflashes your stock ECU with TSP’s proven performance maps — the same kind of tuning you’d get if you mailed your ECU off, except now you can do it yourself in minutes.
Here’s what the ERM puts at your fingertips:
- Flash between multiple maps: Stock and TWO different TSP performance tunes — dial it for terrain, weather, or mood.
- Adjust engine braking: Tame it down so you can brake when you want to, not when the motor grabs.
- Sharpen throttle response: Smooth, instant pull instead of that herky-jerky stock hesitation.
- Monitor live engine data: Throttle position, RPMs, temps, battery voltage — all real time.
- Read and clear fault codes: Diagnose issues without a trip to the dealer.
And if you want full control? Unlock Pro or Pro+ Mode and you can fine-tune individual fuel and ignition tables like a factory race team — no laptop needed.
What It Feels Like After Flashing
- Stronger low-end grunt
- Cleaner mid-range pull
- More predictable throttle everywhere
- Lighter, freer-feeling bike overall
Throttle transitions feel buttery.
Engine braking becomes manageable — no more pitching forward every time you chop the throttle.
And the bike finally rips like a proper KTM should.
What You’ll Need
The TSP ERM works on:
- 2017+ KTM 350 EXC-F / XCF-W
- 2017+ KTM 500 EXC-F / XCF-W
- 2017+ Husqvarna FE 350 / FE 501
- 2021+ GasGas EC-F 350 / 500
👉 Heads Up: If you’re running a USA EXC or FE, you’ll need to de-restrict the bike (pull the reed block, swap the muffler) to get the full benefit. Otherwise, you’re still bottlenecked.
What’s In the Box
- TSP ERM Device
- Handlebar mount
- USB power cable
- Rain/dust cover
- Free download of the TSP performance map
Software updates? No problem. TSP’s ERM Portal lets you stay current as new maps and features roll out.
Why Slavens Racing Backs It
We’ve been tuning these 4-strokes for years.
We know a restricted EXC when we ride one — and we know what they can become once you open them up.
The TSP ERM is hands-down one of the cleanest, most rider-friendly tuning options we’ve ever seen.
You don’t need to ship your ECU. You don’t need a dyno. You just need a T-handle and about 10 minutes.
Once you flash it, you’ll wonder why you didn’t do it sooner.
