James Motorcycles Information Website

James Commodore L25. 250cc. 1957-1962

Homepage Commodore L25 Specification
Identification Specification Sheet Paint & Chrome Transfers (Decals) Manuals
Related topics

James motorcycles.
A brief history.

British Two Stroke Club.
How to join.

Where can I buy....?

Manuals etc.


Other stuff


Frame numbering 1957.  57L25-xxx.  1958. AL25-xxx.   1959.  BL25-xxx etc
Engine AMC 25T.  249cc.  66mm x 73mm
Gears Four speed
Frame Single downtube with fabricated centre section and  swinging-arm rear.
Forks Telescopic.
Tyres 18" x 3.25" front & rear.
Tyre pressures Solo:  Front 16 lbs.psi.  Rear 19 lbs. psi.
Pillion:  Front 16 lbs psi.  Rear 25 lbs psi.
Wheel rims Dunlop WM2 36 hole
Ignition timing " before top dead centre.
Points gap 0.012" - 0.015"
Plug gap 0.018" - 0.022"
Plug type Original spec. Lodge CCL 14
Carburettor AMAL Type 389 / 27.  Bore 1⅛"
Jet size 420
Needle jet 0.105"
Needle setting 2nd groove from top
Tank capacity 2 gallons approximately.  Use of unleaded fuel will cause no problems
Petroil mixture 20:1 as originally specified. Can be safely reduced to 24:1 with modern oils.
Gearbox capacity Remove oil level screw on side of engine casing and oil filler screw on top of casing.  Fill oil through the filler opening until oil begins to run out through the level plug hole. The correct level of oil is then assured.  Check it regularly.  Castrol "D"  SAE 140
Chaincase capacity Fill to plug level
Chains Primary chain:  60 pitches. ⅜" x " x 0.225"
Final drive chain:  127 pitches. " x 0.335" x 0.305" wide.
Sprockets Engine: (crankshaft) 20 teeth  ⅜" pitch.
Gearbox (final drive) 19 teeth " pitch
Rear wheel sprocket 52 teeth
Brakes 6" front & rear
Bulbs Main bulb:  6v - 30 /24w
Tail lamp: 6v - 3w
Stop lamp: 6v - 6v - 18w
Parking lamp bulb: 6v - 3w
Speedo:  6v - 5.3amp.
JamesWisdom@hotmail.com   Simply Wizard