HONDA HHT31S - Manual (Page 61)

TECHNICAL & CONSUMER INFORMATION
59
Tuneup
ENGINE
HHT25S HHT31S
Model GX25 GX31
Engine type 4-stroke, overhead-cam, single-cylinder 4-stroke, overhead-valve, single-cylinder
Displacement 1.5 cu in (25 cc) 1.9 cu in (31 cc)
Bore & stroke 1.4 x 1.0 in (35 x 26 mm) 1.5 x 1.0 in (39 x 26 mm)
Maximum output 1.1 hp (0.82 kW) at 7,000 rpm 1.5 hp (1.1 kW) at 7,000 rpm
Maximum torque 0.8 ft-lbs (1.09 N • m) at 5,000 rpm 1.23 ft-lbs (1.64 N • m) at 4,500 rpm
Ignition system Transistorized magneto
Spark plugs NGK: CMR5H NGK: CR5HSB or DENSO: U16FSR-UB
Starting system Recoil
Fuel Unleaded gasoline (86 octane or higher)
Fuel tank capacity 0.53 qt/16.9 fl.oz (0.50 ) 0.69 qt/22.0 fl oz (0.65 )
Fuel consumption 0.61 lb/hph (370 g/kWh, 276 g/psh) 0.55 lb/hph (340 g/kWh, 250 g/psh)
Oil capacity 2.7 fl oz (80 cc) 3.4 fl oz (100 cc)
Carburetor type Diaphragm type (overflow return) with fuel pump
Air cleaner Single element, semi-dry
Idle speed 3,100 ± 200 rpm
FRAME
HHT25S HHT31S
Ignition switch Slide type
Throttle control Two-motion trigger style
Frame pipe
OD 1.0 in (25.4 mm)
Thickness 0.059 in (1.5 mm)
Drive
Type
Material Flexible steel cable
OD 0.25 in (6.3 mm)
Engagement 0.20 in (5 mm) square drive both ends
Bushing
Material Nylon
Length 57-1/2 inch (1460 mm)
Gear case
Ratio 1.24 (input shaft) : 1 (output shaft)
Type Ball bearings, helical cut gears, no shims required
Clutch
Size 2-1/8 inch 3-1/16 inch
Engagement 4,200 ± 200 rpm
Drive Square female
Type Centrifugal
ITEM SPECIFICATION MAINTENANCE
Spark plug gap
0.024 - 0.028 in
(0.60 - 0.70 mm)
Refer to page 37
Valve clearance
(cold)
HHT25S
Intake: 0.08 ± 0.02 mm
Exhaust: 0.11 ± 0.02 mm
See your authorized
servicing Honda dealer
HHT31S
Intake: 0.12 ± 0.02 mm
Exhaust: 0.15 ± 0.02 mm