| Need photo |
Model
Identification |
| Color |
Luminous Copper |
| Frame number range |
K4S-24701 - 28165 |
| Engine number range |
K4SE033701 - 037169, found on LH top, below
carburetor. |
| Cylinder Mark |
398cc found on front center, below tensioner |
| Engine |
| Engine Type |
4 stroke, 2 - cylinder, SOHC, air cooled, counter balancer |
| Displacement |
398cc |
| Bore X Stroke |
64.0 X 62.0 mm |
| Compression Ratio |
9.5:1 |
| Maximum HP |
34.5 at 8500 rpm |
| Maximum torque |
3.21 kg-m at 7500 rpm |
| Carburetor |
Keihin CV32 (2), constant velocity, diaphragm type |
| Ignition System |
12 Battery & coil, contact breaker |
| Ignition Advance |
Mechanical (centrifugal) |
| Transmission |
Crankshaft Rotation |
Counterclockwise from ignition (RH) side |
| Clutch Type |
Wet, multi-disc, Manual |
Firing Interval |
360° |
| Transmission |
5-speed,constant mesh, return shift |
Cylinder Material |
Aluminum alloy with ferrous sleeve |
| Shift Pattern (bottom Up) |
1-N-2-3-4-5 (w/neutral finder) |
Fuel |
Min 91 Research/87 average oct, unleaded OK |
| Gear ratios |
1st |
2.57 (36/14) |
Tuning
Specifications |
| 2nd |
1.68 (32/19) |
Engine |
| 3rd |
1.27 (28/22) |
Cylinder Head Torque |
Head Nuts |
In sequence 1- 2.0 kg/m 2- 4.0 kg/m |
| 4th |
1.04 (26/25) |
Cover Bolts |
3- 8Ø: 2.5 kg/m 4- 6Ø: 1.0 kg/m 5- Warm up 6-
Retorque cold |
| 5th |
0.89 (24/27) |
Valve Clearance Cold |
Intake |
0.17 - 0.22 mm |
| Primary Ratio |
2.43 (56/23) |
Exhaust |
0.17 - 0.22 mm |
| Final Ratio |
3.00 (45/15) |
Valve Adjustment Method |
Rocker arm screw |
| Overall Ratio (Top Gear) |
6.49 |
Compression Pressure |
11.0 kg/cm² STD 7.7 kg/cm² service limit |
| Chassis |
Spark Plug |
NGK B7ES or ND W22ES-U 0.7 - 0.8 mm gap |
| Wheelbase |
1365 mm |
Point Gap (Dwell) |
0.35 ± 0.05 mm |
| Seat Height |
800 mm |
Ignition Timing |
Idle |
15° BTDC ("F" mark) at 1,100 rpm |
| Ground Clearance |
160 mm |
Full |
35° BTDC (in double marks) at 3,200 rpm |
| Dry Weight |
155 kg |
Pilot Screw (turns out) |
1¼ (Seek highest rpm - install limiter with rib
toward front) |
| Max Recom Load |
155 kg |
Idle Speed |
Lowest stable rpm (usually 1100 ± 100 rpm) |
| Fuel Tank Capacity |
14.0 liter |
Engine Oil |
SE Class SAE 10W40, 10W50, 20W40, 20W50 |
| Tire Size |
Front |
3.00S-18 4PR Tube-Type |
- w/filter change |
2.9 liter |
| Rear |
3.50-18 4PR Tube-Type |
- no filter change |
2.5 liter |
| Brake Type |
Front |
Mechanical Drum (Two Leading) |
- Level |
On center stand, wait 5 min, middle of window. |
| Rear |
Mechanical Drum (Leading/Trailing) |
- Pressure |
More than 2.0 kg/cm² at 4,000 rpm, 90° C |
| Brake Size |
Front |
180 X 30 mm |
Chassis |
| Rear |
160 X 30 mm |
Fork Oil |
SAE 5W20 |
| Suspension Stroke |
Front |
150 mm |
- Capacity |
150cc dry approx 125 cc oil change |
| Rear |
95 mm |
- Level |
417 ± 4 (Fork extended, spring installed) |
| |
Tire Pressure (cold) |
Front |
1.75 kg/cm² |
| Rear (normal) |
2.00 kg/cm² (0 - 97.5 kg) |
| Rear (heavy) |
2.50 kg/cm² (97.5 - 155 kg) |
| Drive Chain Slack |
20 - 25 mm (on center stand, tightest point, STD) |
