Engineered by Ariel for the allround motorcycle segment, the 1957 Ariel FH 650 Huntmaster relies on a 646 cc (39.4 cu in) air-cooled twin, four-stroke powerplant. In factory specification, peak output is rated at 35 HP (25.5 kW) at 5,600 rpm, transferring power to the rear wheel through a 4-speed gearbox and chain final drive. With a specific output of 54.2 HP per liter, the engine character is prioritizing low-RPM tractability, mechanical longevity and relaxed throttle response over peak redline numbers.
On the scales, the FH 650 Huntmaster measures 186 kg (410 lbs) wet (curb), translating to a power-to-weight ratio of 0.19 HP/kg (5.31 kg per horsepower). Rider ergonomics and chassis geometry center around a 787 mm (31 in) seat height — offering a neutral standover height that accommodates most average-inseam riders without sacrificing cornering clearance, combined with a 1,422 mm (56 in) wheelbase engineered for balanced agility and highway composure. The 15.14-liter (4 US gal) fuel tank supports practical everyday commuting and weekend road stints, while factory top speed is listed at 149 km/h (93 mph).
Within MotoLibrary's Ariel archive, this model family spans 2 indexed model years from 1955 to 1957, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Specific Output
54.2 HP/L
Power-to-Weight
0.19 HP/kg (5.31 kg/HP)
Standover Height
787 mm (31 in)
Engine
Displacement646.0 ccm (39.42 cubic inches)
Engine TypeTwin, four-stroke
Engine DetailsBSA A10 engine
Power35.0 HP (25.5 kW)) @ 5600 RPM
Compression6.5:1
Bore x Stroke70.0 x 84.0 mm (2.8 x 3.3 inches)
Fuel SystemCarburettor. Amal
Fuel ControlOverhead Valves (OHV)
IgnitionMagneto
LubricationDry sump, two pumps
CoolingAir
Transmission
Gearbox4-speed
Final DriveChain (final drive)
Performance
Top Speed148.9 km/h (92.5 mph)
ExhaustTwin pipe
Chassis
Frame TypeDuplex down tubes, swingarm
Front SuspensionTelescopic fork, hydraulic
Rear SuspensionDual coil springs
Wheelbase1422 mm (56.0 inches)
Ground Clearance140 mm (5.5 inches)
Wheels & Brakes
Front Tyre3.25-19
Rear Tyre3.50-19
Front BrakesExpanding brake (drum brake)
Rear BrakesExpanding brake (drum brake)
WheelsSteel, wire spokes
Dimensions & Weight
Weight incl.186.0 kg (410.0 pounds)
Seat Height787 mm (31.0 inches) If adjustable, lowest setting.
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Seat Height
Check the seat height against your inseam and riding posture before choosing a motorcycle.
Fuel Capacity
Fuel capacity helps estimate touring range and how often you may need to stop.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.