The GAS GAS MC 85 [2021-2023]: A Youthful Beast with Spanish Flair

When you first lay eyes on the GAS GAS MC 85, it’s clear this isn’t a bike that plays by half-measures. Designed for young riders transitioning from mini-bikes to full-sized motocross machines, the MC 85 carries the torch of GAS GAS’s off-road legacy with a distinctly Spanish flair. Between 2021 and 2023, this model solidified its reputation as a fierce competitor in the 85cc class—a bike that balances raw two-stroke power with surprising refinement. Let’s dive into what makes this machine tick.

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Engine Performance: Two-Stroke Thunder

At the heart of the MC 85 lies a liquid-cooled, single-cylinder two-stroke engine displacing 84.9cc (5.18 cubic inches). For riders raised on the scream of small-bore two-strokes, this motor is pure adrenaline. The carbureted fuel system might feel old-school compared to modern fuel-injected rivals, but it delivers a crisp throttle response that’s hard to fault.

The engine’s character is classic two-stroke: a punchy mid-range that transitions into a wild top-end rush. With a six-speed gearbox and Formula hydraulic clutch, shifting is butter-smooth, letting riders exploit every bit of the powerband. The MEDJ digital ignition ensures reliable starts (via kickstarter, of course) and consistent performance, even when the bike is leaned over in corners.

What’s impressive is how manageable the power feels. Unlike some 85cc bikes that overwhelm with abrupt hits, the MC 85’s delivery is linear enough for developing riders but still packs enough snap to keep veterans entertained. On tight MX tracks, the engine’s willingness to rev pairs perfectly with the lightweight chassis.

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Handling: Lightweight Agility Meets Stability

Weighing in at just 67–68 kg (147.7–149.9 lbs) dry, the MC 85 is a featherweight fighter. The steel central-tube frame with double-cradle design strikes a balance between rigidity and flex, giving the bike a planted feel in ruts while remaining supple over jumps.

The wheelbase sits at 1,137 mm (44.8 inches), which contributes to stability at speed without sacrificing cornering agility. Throw it into a berm, and the bike carves with minimal effort—a trait helped by the Maxxis tires (sizes vary slightly between model years, with front tires ranging from 1.6-17 to 1.6-19 and rears from 2.15-14 to 2.15-16). Ground clearance ranges from 336–377 mm (13.2–14.8 inches), letting you tackle deep ruts or rocky sections without hesitation.

Seat height varies between 865–890 mm (34.1–35.0 inches), accommodating growing riders. Even at its tallest setting, the narrow profile makes it accessible for shorter legs. The real magic, though, is how the bike disappears beneath you mid-ride. It’s flickable yet predictable—a rare combination in this class.

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Suspension & Brakes: WP’s Track-Ready Setup

GAS GAS didn’t cut corners here. The 43 mm WP XACT upside-down fork offers 278 mm (10.9 inches) of travel, while the rear WP XACT monoshock (with linkage on later models) delivers 305–315 mm (12.0–12.4 inches) of wheel travel. Both ends are adjustable for compression and rebound, letting dial in the setup for everything from hardpack to loamy soil.

Out of the box, the suspension is tuned for aggressive riding. Smaller riders might find it stiff initially, but for those pushing the limits, it’s a confidence-inspiring package. The front fork absorbs braking bumps effortlessly, and the rear stays composed under acceleration—even on choppy exit lines.

Braking duties are handled by single discs front and rear. While not as powerful as larger setups, the Formula hydraulics provide ample stopping power for the bike’s weight. The rear brake, in particular, offers excellent modulation for controlling slides.

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Competition: How Does It Stack Up?

In the 85cc motocross segment, the MC 85 faces stiff rivals:

• KTM 85 SX: The Austrian benchmark shares similar WP suspension but edges ahead with a slightly more aggressive powerband. However, the KTM’s seating position feels taller, which some riders find less forgiving.
• Husqvarna TC 85: Essentially a white-and-yellow KTM with a linkage rear suspension, the TC 85 is smoother in mid-corner transitions but lacks the GAS GAS’s playful character.
• Yamaha YZ85: A carbureted holdout like the MC 85, the YZ85 is cheaper but heavier (73 kg / 161 lbs) and lacks modern suspension adjustments.

Where the GAS GAS shines is in its balance. It’s not the outright fastest or lightest, but it blends power, handling, and adjustability into a package that feels race-ready out of the crate.

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Maintenance: Keeping the Fire Alive

Two-strokes thrive on attention, and the MC 85 is no exception. Here’s how to keep it in peak condition:

1. Carburetor Care: The Mikuni carb demands regular cleaning, especially after dusty rides. Consider upgrading to an aftermarket air filter (available at MOTOPARTS.store) for better debris protection.
2. Top-End Rebuilds: Plan for piston replacements every 20–30 hours of hard riding. Keep spare gaskets and rings on hand.
3. Clutch Checks: The Formula hydraulic clutch is robust, but fluid changes (DOT 4) every six months prevent sponginess.
4. Chain & Sprockets: The 1/2 x 5/16´ chain wears quickly under race conditions. Swap in a high-quality O-ring chain and steel sprockets for longevity.

Pro tip: The liquid-cooling system holds ~1.3L of coolant. Use a 50/50 mix of antifreeze and distilled water to prevent overheating during summer motos.

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Final Thoughts

The GAS GAS MC 85 [2021–2023] is a testament to the brand’s off-road DNA. It’s a bike that rewards skill without punishing mistakes—a rare quality in the hyper-competitive 85cc class. Whether you’re blasting out of corners or fine-tuning suspension clickers, this machine makes every ride feel like a podium chase.

And when it’s time to upgrade or replace worn components, MOTOPARTS.store has you covered. From WP fork seals to Maxxis tire sets, we’ve got the parts to keep your GAS GAS biting at the competition’s heels.

Now, go get dirty.

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Specifications sheet

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