Bimota YB4 (1988-1989): A Timeless Dance of Italian Flair and Japanese Precision
Introduction
The Bimota YB4 isn’t just a motorcycle—it’s a statement. Born from the marriage of Italian design audacity and Yamaha’s engineering prowess, this late-’80s exotic machine remains a fever dream for collectors and riding purists. With only two years of production, the YB4 is a rare gem that combines track-focused aggression with artisanal craftsmanship. Having recently spent time with a meticulously preserved example, it’s clear why this bike still commands reverence in garage-queen circles and café racer debates alike.
Design: Rolling Sculpture Meets Function
The YB4’s design is a masterclass in pre-digital-era motorcycle aesthetics. The tubular steel trellis frame isn’t just structural—it’s the bike’s exoskeleton, proudly visible beneath the minimalist bodywork. The 42mm Marzocchi telescopic forks (a rarity in an era of rising upside-down designs) give the front end a clean, industrial look, while the single-sided swingarm—a Bimota signature—turns routine parking into a photo op.
The bodywork, draped in period-typical angular lines, hides a 20-liter fuel tank (5.3 gallons) that’s surprisingly svelte for its capacity. The seat? A thinly padded affair that whispers, "You’ll stop when the fuel runs out." Every vent, duct, and fastener feels purpose-built, yet the overall effect is less "factory racer" and more "Michelangelo’s David in carbon fiber."
Performance: 120 Horses, Zero Compromises
At its heart lies Yamaha’s FZ750-derived, 749cc inline-four engine—tuned to a staggering 120 PS (88 kW) at 10,500 RPM. For context, that’s 118 horsepower in a machine weighing just 185 kg (408 lbs) dry. Modern riders used to turbocharged torque might find the power delivery quaintly analog: a crescendo building from 6,000 RPM to a stratospheric 12,500 RPM redline.
Throttle response is immediate, thanks to Bimota’s proprietary intake and exhaust tuning. The engine’s 16-valve DOHC architecture, paired with Keihin CV carburetors, delivers a linear surge rather than a binary switch—a trait that rewards skilled wrists. Top speed? A claimed 255 km/h (158 mph), though surviving period reviews suggest 240 km/h (149 mph) was more realistic. Either way, it’s a number that still raises eyebrows.
Handling: Telepathic, If You’re Worthy
The YB4’s chassis is where Bimota’s genius shines. The steel trellis frame, paired with a fully adjustable Sachs monoshock and those 42mm Marzocchi forks, creates a ride that’s taut but never punishing. At lean, the bike feels like it’s pivoting around an invisible axis—a combination of the 54.5-inch wheelbase and near-perfect 50/50 weight distribution.
Push hard into a corner, and the 130/70-16 front tire (a period-specific oddity) telegraphs grip levels with surprising clarity. The Brembo brakes—dual 300mm discs up front—lack modern ABS but offer a raw, progressive bite. This isn’t a bike that tolerates ham-fisted inputs, but for riders who’ve mastered the art of smooth, it’s a ballet partner in leathers.
Competition: David Among Goliaths
The late ’80s sportbike arena was a thunderdome. Here’s how the YB4 stacked up:
- Ducati 851 (1988-1990): The Italian rival boasted fuel injection and an 851cc V-twin, delivering 93 PS (68 kW). While the Ducati’s desmo valves were maintenance-heavy, its torquier engine made it friendlier on bumpy B-roads. The YB4, however, dominated in outright speed and track precision.
- Honda RC30 (1987-1990): Honda’s VFR750R homologation special had 112 PS (82 kW) and a legendary V4. The RC30 was more reliable and easier to live with, but the YB4’s bespoke chassis offered purer handling.
- Yamaha FZR 1000 (1987-1991): Sharing DNA with the YB4’s engine, the FZR packed 135 PS (99 kW) from a 1002cc mill. It was faster in a straight line but weighed 30 kg (66 lbs) more, feeling portly by comparison.
The YB4’s Achilles’ heel? Exclusivity. With only ~400 units built, finding parts was—and still is—a treasure hunt.
Maintenance: Keeping the Legend Alive
Owning a YB4 today is equal parts privilege and project. Here’s what to watch:
- Spark Plugs: The twin-plug head uses NGK DR8EA (standard) or DR8EIX (iridium). Gap them to 0.7mm (0.028 in) for optimal combustion. Iridiums last longer but lack the vintage “authenticity.”
- Cooling System: The “Wasser+” coolant specification translates to a 50/50 ethylene glycol mix. Overheating is rare, but check the radiators for corrosion—they’re unobtanium if damaged.
- Brake Fluid: DOT 4 is a must. Upgrade to a high-temperature racing fluid if you’re tracking the bike.
- Carb Tuning: Keihin CVs are reliable but sensitive to ethanol-blended fuels. Consider a MOTOPARTS.store ethanol-resistant rebuild kit.
Pro Tip: The single-sided swingarm’s pivot bearings wear faster than expected. Lubricate annually with lithium-based grease.
Conclusion: The Uncompromised Dream
The Bimota YB4 isn’t a motorcycle for the faint of wallet or mechanical aptitude. It’s a time capsule from an era when "homologation special" meant actual race tech, not marketing fluff. Riding it today feels like unearthing a lost Stradivarius—every input resonates with purpose, every glance at the garage sparks joy.
For MOTOPARTS.store shoppers, the YB4 represents a golden opportunity: a chance to own a legend while knowing our catalog has the NGK plugs, Brembo pads, and chassis upgrades to keep it singing. After all, maintaining exotic history is just another ride in the twisties.
“Perfection is achieved not when there is nothing more to add, but when there is nothing left to take away.” Bimota’s engineers clearly took Antoine de Saint-Exupéry to heart.
