News Releases 2004

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February 20, 2004

Honda Announces a Full Model Change for the Sporty Smart Dio Z4 50cc Scooter- Featuring the world's first electronic fuel injection system for a production 4-stroke 50cc engine -

February 20, 2004-Honda Motor Co., Ltd. has announced a full model change for the sporty Smart Dio Z4. The new Smart Dio Z4 features the world's first*1electronic fuel injection system (Honda Programmed Fuel Injection System, or PGM-FI) in a 4-stroke, 50cc scooter, for improved fuel economy and cleaner emissions along with superb startup and responsiveness. The new model will go on sale February 21, 2004. 

The Smart Dio Z4 made its debut in March 2002, equipped with a water-cooled, 4-stroke, 50cc engine for improved environmental performance, a comfortable ride, and superior fuel economy. This, along with its sporty exterior design, has made it a popular favorite especially among younger riders. 

The new model is equipped with PGM-FI-a world's first for a 4-stroke 50cc engine-resulting in even cleaner exhaust emissions and fuel economy of 80km/L*2. The engine also features a 4-valve head, another world's first*3 for a 50cc scooter, to ensure powerful low-rpm acceleration and spirited driving performance. The PGM-FI and 4-valve head combine to provide stable idling performance and outstanding startup regardless of changes in temperature, barometric pressure, and other environmental conditions, along with outstanding responsiveness. The scooter can also be started using the kick starter even when the battery is completely dead, for increased convenience.

*1 According to Honda in-house testing
*2 30km/h low-altitude driving
*3 Based on Honda’s investigation

Smart Dio Z4

Smart Dio Z4

●Annual domestic sales target: 10,000 units
●Manufacturer's suggested retail price: ¥199,000

(For reference only. Consumption tax not included.)

The exterior design has been comprehensively refined, creating a sharper, more sporty style.
For the running gear, a new hydraulic telescopic suspension with 2-piece bottom has been added, complementing the existing front disc brake and front and rear aluminum cast wheels and providing nimbler, sportier handling.

The new Smart Dio Z4 is available in two colors: intrepid Vega Black Metallic and refreshing Pearl Seashell White.

All Honda scooters for sale in Japan are scheduled to offer PGM-FI by the end of 2007.

=Key Features=

  • World’s first PGM-FI and 4-valve head in a 4-stroke, 50cc scooter
    Exhaust emissions reach just half the level of Japanese government standards for both CO (carbon monoxide) and HC (hydrocarbons), while fuel economy has been improved by approximately 7%, to 80km/L during 30km/h low-altitude driving. Engine startup performance at low temperatures and after extended periods of disuse has also been significantly improved over the previous, carburetor-equipped model. And the scooter can be kick-started even when the battery is completely dead, even though the PGM-FI system requires an electrical supply for operation.
  • More refined, sporty styling
    The exterior design has been comprehensively refined, creating a sharper, more sporty style. The front turn-signal cover has been redesigned with a sharper form, and the emblems ‘PGM-FI’ and ‘4-VALVES’ are located on the front and rear sides. The large rear spoiler sports a built-in high-mount stop lamp with red LED (light-emitting diode) lighting, complemented by a tail light with new blue outer lens and turn signals in a unitized combi-lamp design that imparts added sharpness to the rear styling. The muffler protector is chrome plated for more of a quality feel.
  • Running gear designed for enhanced handling performance
    In the front, a new hydraulic telescopic suspension with 2-piece bottom has been added to go with the hydraulic disc brakes. In the rear, a double-action hydraulic shock absorber combines with a red rear suspension coil to impart a sporty feel, while lightweight cast aluminum wheels front and rear and other features add to the scooter’s nimble, sporty handling.
  • Combined-brake system makes even novice riders feel at ease
    The new Smart Dio Z4 comes equipped with a combined-brake front-rear brake-force distribution system, that distributes an appropriate balance of front and rear wheel braking force when only the left (rear wheel) brake lever—the one that novice riders most often use— is squeezed. This system, a Honda original, helps even novice riders stop efficiently while maintaining vehicle stability.
  • Anti-theft system with enhanced security
    The existing anti-theft system features a key cylinder that offers centralized control of the main ignition switch, seat opener, and reinforced handle lock. The key cylinder is also equipped with a shutter-like protective cover. The Smart Dio Z4 is also equipped with Honda’s own original center stand locking system, which locks the center stand in place for added security, along with a direct startup prevention circuit and a key-lock equipped fuel tank cap. The scooter is also pre-wired for an optional alarm kit*1or immobilizer alarm*1 for heightened security.
  • *1Manufactured by Honda Access Corporation. Sold separately.
  • Additional features
  • Black instrument panels for superior visibility. Equipped with FI function indicator.
  • Seat features a sports-type non-slip covering.
  • Large-capacity 22L* storage compartment provides ample space for an A4-size file folder or a full-face helmet.
  • Maintenance-free battery does not require water top-ups.
  • *According to Honda in-house testing


Model Name Dio Z4
Model Type Honda·BA-AF63
L x W x H (m) 1.710×0.630×1.010
Wheelbase (m) 1.190
Ground Clearance (m) 0.110
Seat Height (m) 0.710
Vehicle Weight (kg) 81
Dry Weight (kg) 77
Number of Riders 1
Turning Radius (m) 1.8
Engine Type AF63E (water-cooled 4-stroke OHC 4-valve single cylinder)
Displacement (cm3) 49
Bore x Stroke (mm) 38.0×44.0
Compression Ratio 12.0
Max· Power (kW[PS]/rpm) 3.9[5.3]/8,000
Max· Torque (N·m[kg·m]/rpm) 4.8[0.49]/7,500
Fuel Consumption (km/L) 80.0 (30km/h low-altitude driving)
Fuel System Electronic fuel injection (PGM-FI)
Starter Self-starting (also kick-start)
Ignition Fully transistorized battery ignition
Lubrication Combination pressure/splash
Fuel Tank Capacity (L) 4.8
Clutch Dry, multi-plate shoe
Gearbox Constant mesh (V-matic)
Gear Ratio 1 gear 2.800 ~ 0.860
Caster Angle (degrees)/Trail (mm) 26°30´/72
Tire Size Front 90/90-10 50J
Rear 90/90-10 50J
Braking System Front Hydraulic disc
Rear Mechanical leading/trailing
Suspension Front Telescopic
Rear Unit-swing type
Frame Underbone