Posted by Slavens Racing on February 25, 2025
What are the top performance parts for a KTM TBI? We answer that question.
If you’ve got a KTM TBI—a throttle-body-injected two-stroke—you’re already on a solid machine. you know they’re solid out of the box. But “solid” ain’t enough when you’re chasing that next level of performance.
For riders looking to unlock more grunt, sharper response, and a ride that truly fits their style, Two Stroke Performance (TSP) has the goods. We’re talking about their ECU Reflash Module (ERM), High Compression Cylinder Head, Piston Kit, and Oversized Power Valve Cover.
These parts don’t mess around—they deliver real results. Let’s dive into what each one brings to your KTM TBI and why they’re worth your time.
TSP ECU Reflash Module (ERM): Fine-Tune Your Ride
The TSP ECU Reflash Module, or ERM, is where it all starts. Stock ECU tunes on a TBI are held back—lean fuel maps, sluggish low-end response, and that annoying pipe bang when you’re pushing it.
The ERM rewrites that script. It’s a plug-and-play tuner that tweaks fuel, ignition, power valve settings, and even oil delivery, with custom Green and White maps you can swap on the fly. Green’s your “scalded dog” mode—crisp throttle, max power. White’s softer, richer, perfect for technical singletrack or deep sand.
This isn’t just a gimmick. It smooths out the power curve, wakes up the throttle, and keeps your engine running strong under load. TSP’s dyno work backs it up, and the built-in diagnostics are a nice bonus. For 2024+ KTM 250/300 TBI models (XC-W, EXC), it’s a game-changer—no waiting on mail-in flashes, just instant tuning you control. Pair it with other mods, and you’ve got a bike that’s dialed in exactly how you want it.
TSP High Compression Cylinder Head: Boost the Bottom End
The TSP High Compression Cylinder Head is all about adding punch where it counts. Machined from tough 6061 T6 aluminum, this two-piece setup (shell and dome) cranks up compression for better low- and mid-range power. Think more torque out of corners and a snappier feel without sacrificing reliability. It’s got tighter squish clearance than stock, so you’re burning fuel more efficiently—less heat, more go.
You’ve got choices here: Medium Comp for sea-level riders (runs fine on 91 octane), High Comp for maximum low-end kick, and Very High Comp for high-altitude shredders above 4,900 feet. It’s a straightforward swap for ‘23+ KTM SX/XC/EXC models, and the difference is instant. Match it with the ERM for a custom tune, and your 250 or 300 TBI will feel like a whole new animal.
TSP Piston Kit: Strength Meets Performance
The TSP Piston Kit is your ticket to a tougher engine. OEM pistons are fine, but when the stock one kicks the bucket, you might as well upgrade. TSP’s kits come in A or B sizes to match your cylinder’s wear (A for under lower hours, B for older bores). For 125 TBI owners, the 12° version is a standout—its beveled edge keeps ports open longer, smoothing the fuel charge and boosting top-end pull while holding compression steady. For 250/300s, the standard kit uses gravity-cast aluminum with 18% silicon, heat-treated for durability.
What’s the payoff? Consistent performance for a long time under serious abuse. Everything’s included—piston, rings, pin, clips—for an easy install. Whether you’re on a ‘23+ 125 TBI or a ‘18-24 KTM 85 SX, this keeps your motor running strong.
TSP Oversized Power Valve Cover: Torque You’ll Notice
The TSP Oversized Power Valve Cover rounds out the lineup with a focus on low-end grunt. It increases the power valve chamber volume on your 250/300 TBI, softening exhaust pulses that rob torque at low RPMs. The result is stronger pull between 3,000-5,000 RPM—perfect for trail riders or anyone tackling technical terrain. TSP’s in-house shows a fatter torque curve and smoother delivery on the dyno. The Slavens Racing field testing confirms it as a hit.
It’s built for ‘23+ KTM SX/XC/EXC models, anodized for durability, and bolts on in minutes. This isn’t about top-end scream—it’s about usable power where most of us ride. Add it to a setup with a Medium Comp head and ERM, and you’ve got a bike that’s ready for anything.
Why It Matters
Your KTM TBI is a beast waiting to be unleashed, and Two Stroke Performance’s lineup gets it there. The ERM tunes it right, the High Compression Head and Piston Kit crank up the power, and the Oversized Power Valve Cover fills in the gaps. Together, they turn a good bike into a great one—more responsive, more durable, and flat-out more fun to ride.
At Slavens Racing, we’ve got all these parts in stock, tested by riders who live for this stuff. Ready to upgrade?
Slavens Racing Team
