Husqvarna TC 125 [2018-2020]: A Motocross Weapon Built for Precision

Introduction

The Husqvarna TC 125 represents the pinnacle of lightweight two-stroke motocross engineering. Part of Husqvarna's race-ready TC lineup, this 125cc machine from the 2018-2020 generation delivers a thrilling mix of razor-sharp handling, explosive power delivery, and Swedish design sophistication. Designed for riders who demand precision on technical tracks, it’s a bike that rewards skill and punishes complacency. After spending time with this machine on tight MX circuits and open practice tracks, it’s clear why it remains a favorite among competitive riders and two-stroke enthusiasts.

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Engine Performance: Two-Stroke Fury Refined

At the heart of the TC 125 lies a liquid-cooled 124.8cc single-cylinder two-stroke engine producing 40 HP (29 kW). This isn’t just any 125cc mill – it’s a meticulously tuned powerplant that combines old-school two-stroke aggression with modern reliability. The 54 x 54.5 mm bore/stroke ratio prioritizes high-RPM power, while the reed valve intake and Mikuni TMX 38 carburetor (pre-2020 models) ensure crisp throttle response.

On the track, the engine character is unmistakably "light-switch" – a gentle growl at low revs that erupts into a frenzied scream as the power valve opens. The hit comes hard around 8,000 RPM, demanding precise clutch work to keep it in the meat of the powerband. Riders accustomed to four-strokes will need to recalibrate their reflexes, but those who master the TC’s delivery are rewarded with explosive overtaking potential.

Key upgrades over earlier models include:
- Magura hydraulic clutch for consistent lever feel
- 6-speed transmission with wider ratio spread
- MEDJ digital ignition for optimized timing

Fuel capacity varies slightly between model years (7-8 liters / 1.85-2.11 gallons), but all share the same philosophy: keep weight centralized and let riders focus on short, aggressive sessions.

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Chassis & Suspension: Swedish Scalpel

The TC 125’s chrome-molybdenum steel frame is a work of art, combining 25CrMo4 steel main sections with laser-cut brackets. At just 87.5 kg (193 lbs) dry, it’s 2-3 kg lighter than most competitors while maintaining exceptional torsional rigidity. Paired with the CNC-machined triple clamps and WP suspension, this creates a chassis that communicates like a nervous system extension.

Front Suspension
The WP AER 48 USD fork (48mm diameter) offers 310mm (12.2") of travel with separate air/oil chambers. Unlike traditional spring forks, the air system allows for easy preload adjustments via a Schrader valve. During hard landings, the fork maintains composure, only becoming slightly harsh on square-edge bumps at low speeds.

Rear Suspension
A WP DCC shock with 300mm (11.8") travel handles rear duties. The linkage ratio provides excellent mid-stroke support, preventing wallowing through whoops while remaining plush on small chatter.

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Handling & Ergonomics

With a 1,485mm (58.5") wheelbase and 26.1° rake, the TC 125 changes direction like a trials bike. The 950mm (37.4") seat height feels tall for shorter riders but provides crucial legroom when attacking berms. Bodywork is slim – knees grip effortlessly against the shrouds, while the flat seat profile allows easy weight shifts.

The Brembo braking system deserves special mention:
- 260mm front rotor with twin-piston caliper
- 220mm rear rotor with single-piston caliper
Stopping power is monumental for a 125, with excellent modulation that prevents endos during steep descents.

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Competition: How It Stacks Up

1. KTM 125 SX (2018-2020)
The TC’s Austrian cousin shares its engine and suspension but differs in chassis tuning. KTM’s frame is slightly stiffer, favoring aggressive riders, while Husqvarna’s setup offers more feedback on slick tracks. The TC also gains premium touches like a Pro Taper handlebar.

2. Yamaha YZ125 (2018-2020)
Yamaha’s stalwart relies on a decades-old engine design but counters with legendary reliability. The YZ feels heavier (96 kg/212 lbs) and less frantic, making it better suited for casual riders. However, the TC dominates in suspension sophistication and outright power.

3. TM MX 125
The Italian exotic boasts hand-built quality and explosive power but suffers from limited parts availability. Husqvarna’s dealer network and aftermarket support give the TC a decisive edge.

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Maintenance: Keeping the Beast Alive

1. Top-End Rebuilds
As with all high-strung two-strokes, piston replacement is critical. Monitor compression monthly:
- <120 PSI (8.3 bar): Time for a rebuild
- Use genuine Husqvarnal piston kits for optimal port matching

2. Suspension Service
WP AER forks require special attention:
- Clean air filter monthly
- Rebuild internals every 50 hours
Consider upgrading to SKF seals for muddy conditions.

3. Carburetor Tuning
The Mikuni TMX can be finicky. Keep these MOTOPARTS.store items on hand:
- Jet kit (P/N: MIK-125JET)
- Float bowl gaskets
- Adjustable air screw

4. Chain & Sprockets
The 520 chain wears quickly under hard use. Replace with DID ERVT3 chains and hardened steel sprockets for longevity.

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Conclusion: A Legacy of Precision

The 2018-2020 Husqvarna TC 125 isn’t just a motocross bike – it’s a statement. For riders willing to embrace its high-strung nature, it offers a level of tactile engagement that four-strokes can’t match. While newer fuel-injected models have since emerged, this generation remains a benchmark for analog intensity.

At MOTOPARTS.store, we carry everything to keep your TC 125 at peak performance – from WP seal kits to Pro Taper upgrades. Whether you’re chasing national titles or local bragging rights, this Husqvarna deserves to be fed the best.

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Specifications sheet

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