Technical Information

Wiring Diagram

Principle Wiring diagram (Courtesy of OldTimer)

Amal 398 Carburettor Butterfly Type

Useful Data

Length - 2.10 m (6 ft 11 in)
Width - 0.75 m (2 ft 5½ in)
Height - 1.08 m (3 ft 6½ in)
Weight - 158.75kg (350 lbs)
Engine - 343 cc

Capacities:

Fuel Tank - 3.5 Gallons (15.911 ltrs)
Gearbox - 0.67 pints (.3786 ltrs)
Engine - 5 pints (2.841 ltrs)
Primary - 0.5 pints (.284 ltrs)
Forks each leg - 0.34 pints (.1893 ltrs)

Settings/info:

Plug gap - .020 in - .025 in
Points gap - .015 in
Timing - 7.112 mm BTDC fully advanced
Piston ring fitted gap - (Maximum .014 in or .3556 mm)
(Minimum .009 in or .2283 mm)
Compression ratio - 7.0 : 1

Valve springs:

Free Length (inner) - 1.625 in. (41.275 mm)
Free Length (Outer) - 2.03125 in. (51.5937 mm)
tappet Clearence (cold)
Inlet - .008 in (.2032 mm)
Exhaust - .010 in (.254 mm)

Cylinder barrel:

Bore size (Standard) - 79 mm
Stroke - 70 mm

Carburetter:

Type - Amal 398/6
Main jet - 210
Pilot jet - 25
Nominal choke size - 26 mm

Clutch:

Driving plates - 4
Plain plates - 5
Overall thickness of driving plate - .167 in (4.242 mm)
Free length of clutch springs - 1.65685 in (42.0687 mm)
Clutch push rod length - 9.0 in (228.6 mm)
Clutch push rod Dia - .1875 in (4.7225 mm)

Electrical:

Alternator type - Lucas R.M.19
Contact breaker - Lucas 4CA
Coil - Wipac S.0810
Rectifier - Lucas 2DS506
Zener Diode - Lucas ZD715

Sprockets:

Engine - 23 teeth
Clutch - 52 teeth
Gearbox - 18 teeth
Rear wheel - 52 teeth

Chain sizes - Duplex .375 in. x 70 pitches

Front Forks:

Spring fee length - 10.375-10.50 in
Spring rate - 25/27 lb in
Number of coils - 21½

Back to Top of Page