Yamaha XS1100RH #000299
The Yamaha XS1100 Legacy
When Yamaha introduced the XS1100 (popularly known as the "XS Eleven") in late 1977 for the 1978 model year (E model), it sent shockwaves through the motorcycle industry. Powered by an air-cooled, DOHC 1,101cc inline-four engine delivering a staggering (for the time) 95 horsepower, the XS Eleven was built to reclaim top-tier performance honors in the hyper-competitive Japanese superbike arms race. Utilising a heavy-duty Hy-Vo primary drive chain and a virtually indestructible shaft final drive, it quickly earned a reputation as an unstoppable muscle bike capable of scorching quarter-mile times in the mid-11-second range straight off the showroom floor.
As the model line progressed through the late 1970s and early 1980s, Yamaha broadened the XS1100 family across multiple designations (E, F, G, and H models). Alongside the standard roadster versions, Yamaha pioneered the factory-custom aesthetic with the "Special" models, featuring teardrop fuel tanks, stepped seats, pullback handlebars, and shorty exhaust pipes. Despite its significant weight and a chassis that prioritised high-speed stability over tight-fisted agility, the XS Eleven proved remarkably versatile—dominant in endurance racing victories like the Australian Castrol Six Hour and beloved by cross-country touring riders for its effortless power and low-maintenance shaft drive.
By the turn of the decade, the superbike landscape was evolving toward lighter, sharper-handling sports machines. Rather than retiring the platform, Yamaha gave the XS Eleven a grand finale for 1981, culminating in the H-series. This generation represented the absolute peak of the model's development, refining the rock-solid electronics, electronic ignition with vacuum advance, and bulletproof bottom-end architecture into the most polished version of the 1,101cc engine Yamaha ever produced.
The 1981 XS1100RH: The Black Beast of Excess
Naming conventions preface:
The motorcycle was marketed in the Oceania region (primarily Australia and New Zealand) as the XS1100R, but it was also referred to in official Yamaha customer facing documents such as service manuals, and part lists, as the XS1100RH. To complicate things further Yamaha also used an engine and chassis prefix of 5N5. For the purpose of consistency within this document, we will use the term XS1100RH.
Sitting at the very pinnacle of this evolution was the 1981 Yamaha XS1100RH which was also positioned in European markets as the XS1100S (Sport) or "Bête Noire". Unlike the standard touring-oriented XS1100H or the laid-back Midnight Special, the RH was engineered as a dark, aggressive factory cafe-racer that embraced a somberly clad aesthetic. Drenched almost entirely in black—from the engine block, frame, and side panels to the mudguards, seat, and twin-exhaust pipes—the RH was visually relieved only by subtle gold highlighting on the cast wheels and brake discs, a bright cover on the air filter box, and a tinted flyscreen veil across its front cowling.
Mechanically, the XS1100RH set itself apart from the standard XS1100H with targeted engine modifications designed for punchier, lower-end punch. Yamaha fitted the RH cylinder head with significantly larger intake valves—stepping up to 36mm inlets compared to the 31mm valves on the standard XS. This alteration boosted low-rpm cylinder filling, shifting peak torque down to 66.5 lb-ft at just 4,000 rpm (compared to the standard model's 6,000 rpm peak). While top-end power remained rated at 95 bhp at 8,500 rpm, the RH’s revised breathing gave it unmatched roll-on overtaking ability in top gear, allowing riders to effortlessly surge past traffic with a simple wrist twist without needing to step down through the gearbox.
The chassis and geometry of the XS1100RH received an equally extensive overhaul to transform its road manners. Yamaha altered the steering head angle to a steeper 29 degrees of castor, sharpening front-end turn-in and giving the bike a considerably less ponderous feel in corners than its predecessors. To manage the 600lb wet weight under spirited riding, the suspension was upgraded to air-assisted telescopic front forks (pressurised up to 36 psi) and rear swingarm shocks featuring five-way adjustable spring preload collars alongside four-way adjustable rebound damping. Braking duties were handled by three heavy-duty 11.75-inch hydraulically operated discs featuring three slotted cutouts per rotor for enhanced cooling and progressive, fade-free retardation.
Ergonomically and functionally, the XS1100RH was built specifically for high-speed sport-touring. It came equipped with a compact, handlebar-mounted flyscreen fairing that took the wind blast off the rider's chest, fully adjustable handlebars, and a sporty dual seat flanked by robust grab bars. It swapped the standard model's float based fuel gauge for a thermistor based low-fuel warning light that flashed approximately 15 kilometers before reserve. Although fitted with a smaller 3.3-gallon fuel tank to maintain its sleek profile (though interchangeable with the standard 5.3-gallon tank), the RH was comprehensively fitted with two steering locks, and a hidden padlock chain (Yellow on the RH, Black on the "S").
Ultimately, the 1981 XS1100RH stands as a rare and captivating chapter in Yamaha's history—a machine that combined the proven, bulletproof brute force of the original XS Eleven with sophisticated chassis tuning and an unmistakable, head-turning style.
References & Historical Sources
-
1981 Factory Road Test & Technical Review: "Bête Noire: The Black Beast of Excess," Motorcycle Magazine (UK Edition, November 1981). Covers performance metrics, 36mm valve modifications, 29° steering geometry, air-assisted front forks, 4-way rebound adjustable rear shocks, fuel system thermistor operation, and physical equipment specifications.
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Yamaha Factory Technical Documentation: Yamaha XS1100RH Supplementary Service Manual (Yamaha Motor Co., Ltd., Publication No. 5N5-28197-60) and Yamaha Global Model Identification Index. Details model prefix 5N5, regional nomenclature variations (XS1100R / XS1100RH), and chassis/engine serial ranges.
-
Model Lineage & Racing History: "Yamaha XS1100 — Cycle World Classics Remembered" (Cycle World Magazine) and "The Days of XS: Everything You Need to Know About the Yamaha XS1100" (Old Bike Barn). Covers global model development (E through H series), "Special" styling lineage, and Australian Castrol Six Hour endurance racing achievements.
The Yamaha XS1100 Legacy
When Yamaha introduced the XS1100 (popularly known as the "XS Eleven") in late 1977 for the 1978 model year (E model), it sent shockwaves through the motorcycle industry. Powered by an air-cooled, DOHC 1,101cc inline-four engine delivering a staggering (for the time) 95 horsepower, the XS Eleven was built to reclaim top-tier performance honors in the hyper-competitive Japanese superbike arms race. Utilising a heavy-duty Hy-Vo primary drive chain and a virtually indestructible shaft final drive, it quickly earned a reputation as an unstoppable muscle bike capable of scorching quarter-mile times in the mid-11-second range straight off the showroom floor.
As the model line progressed through the late 1970s and early 1980s, Yamaha broadened the XS1100 family across multiple designations (E, F, G, and H models). Alongside the standard roadster versions, Yamaha pioneered the factory-custom aesthetic with the "Special" models, featuring teardrop fuel tanks, stepped seats, pullback handlebars, and shorty exhaust pipes. Despite its significant weight and a chassis that prioritised high-speed stability over tight-fisted agility, the XS Eleven proved remarkably versatile—dominant in endurance racing victories like the Australian Castrol Six Hour and beloved by cross-country touring riders for its effortless power and low-maintenance shaft drive.
By the turn of the decade, the superbike landscape was evolving toward lighter, sharper-handling sports machines. Rather than retiring the platform, Yamaha gave the XS Eleven a grand finale for 1981, culminating in the H-series. This generation represented the absolute peak of the model's development, refining the rock-solid electronics, electronic ignition with vacuum advance, and bulletproof bottom-end architecture into the most polished version of the 1,101cc engine Yamaha ever produced.
The 1981 XS1100RH: The Black Beast of Excess
Naming conventions preface:
The motorcycle was marketed in the Oceania region (primarily Australia and New Zealand) as the XS1100R, but it was also referred to in official Yamaha customer facing documents such as service manuals, and part lists, as the XS1100RH. To complicate things further Yamaha also used an engine and chassis prefix of 5N5. For the purpose of consistency within this document, we will use the term XS1100RH.
Sitting at the very pinnacle of this evolution was the 1981 Yamaha XS1100RH which was also positioned in European markets as the XS1100S (Sport) or "Bête Noire". Unlike the standard touring-oriented XS1100H or the laid-back Midnight Special, the RH was engineered as a dark, aggressive factory cafe-racer that embraced a somberly clad aesthetic. Drenched almost entirely in black—from the engine block, frame, and side panels to the mudguards, seat, and twin-exhaust pipes—the RH was visually relieved only by subtle gold highlighting on the cast wheels and brake discs, a bright cover on the air filter box, and a tinted flyscreen veil across its front cowling.
Mechanically, the XS1100RH set itself apart from the standard XS1100H with targeted engine modifications designed for punchier, lower-end punch. Yamaha fitted the RH cylinder head with significantly larger intake valves—stepping up to 36mm inlets compared to the 31mm valves on the standard XS. This alteration boosted low-rpm cylinder filling, shifting peak torque down to 66.5 lb-ft at just 4,000 rpm (compared to the standard model's 6,000 rpm peak). While top-end power remained rated at 95 bhp at 8,500 rpm, the RH’s revised breathing gave it unmatched roll-on overtaking ability in top gear, allowing riders to effortlessly surge past traffic with a simple wrist twist without needing to step down through the gearbox.
The chassis and geometry of the XS1100RH received an equally extensive overhaul to transform its road manners. Yamaha altered the steering head angle to a steeper 29 degrees of castor, sharpening front-end turn-in and giving the bike a considerably less ponderous feel in corners than its predecessors. To manage the 600lb wet weight under spirited riding, the suspension was upgraded to air-assisted telescopic front forks (pressurised up to 36 psi) and rear swingarm shocks featuring five-way adjustable spring preload collars alongside four-way adjustable rebound damping. Braking duties were handled by three heavy-duty 11.75-inch hydraulically operated discs featuring three slotted cutouts per rotor for enhanced cooling and progressive, fade-free retardation.
Ergonomically and functionally, the XS1100RH was built specifically for high-speed sport-touring. It came equipped with a compact, handlebar-mounted flyscreen fairing that took the wind blast off the rider's chest, fully adjustable handlebars, and a sporty dual seat flanked by robust grab bars. It swapped the standard model's float based fuel gauge for a thermistor based low-fuel warning light that flashed approximately 15 kilometers before reserve. Although fitted with a smaller 3.3-gallon fuel tank to maintain its sleek profile (though interchangeable with the standard 5.3-gallon tank), the RH was comprehensively fitted with two steering locks, and a hidden padlock chain (Yellow on the RH, Black on the "S").
Ultimately, the 1981 XS1100RH stands as a rare and captivating chapter in Yamaha's history—a machine that combined the proven, bulletproof brute force of the original XS Eleven with sophisticated chassis tuning and an unmistakable, head-turning style.
References & Historical Sources
-
1981 Factory Road Test & Technical Review: "Bête Noire: The Black Beast of Excess," Motorcycle Magazine (UK Edition, November 1981). Covers performance metrics, 36mm valve modifications, 29° steering geometry, air-assisted front forks, 4-way rebound adjustable rear shocks, fuel system thermistor operation, and physical equipment specifications.
-
Yamaha Factory Technical Documentation: Yamaha XS1100RH Supplementary Service Manual (Yamaha Motor Co., Ltd., Publication No. 5N5-28197-60) and Yamaha Global Model Identification Index. Details model prefix 5N5, regional nomenclature variations (XS1100R / XS1100RH), and chassis/engine serial ranges.
-
Model Lineage & Racing History: "Yamaha XS1100 — Cycle World Classics Remembered" (Cycle World Magazine) and "The Days of XS: Everything You Need to Know About the Yamaha XS1100" (Old Bike Barn). Covers global model development (E through H series), "Special" styling lineage, and Australian Castrol Six Hour endurance racing achievements.