classic motorcycle forum

The Mk II designation on the underside of the float bowl refers to general improvements across the whole Villiers carburettor range. It serves no other purpose and has no role in identifying any individual part or individual carburettor. Ignore it.

Your 1 1/8" carburettor is a Villiers MW (Medium Weight). It is intended for use with a Villiers lever throttle NOT a later self closing twistgrip throttle.

The Mk XIIC was fitted with the MW (Medium Weight) carburettor as standard. It was set up with a number 2 jet (the centrepiece) and a number 4 taper needle. Both the jet (centrepiece) and taper needle are stamped with the relevant numbers. Be aware it is very easy for the MW needle and centrepiece to be confused with the similar but shorter parts used in the Villiers LW (Light Weight) carburettor. It is easy to confuse the two.

If all parts are in good condition with the float level set to Villiers specifications the carburettor will work exactly as the maker intended without any further adjustment. Please note there is often a difference between what the maker intended and what a current owner thinks it should do. 

The two tags look to be spring clips of some sort, so it must be part of the bodywork? If there isn't a comparable-sized hole in the pressed steel for it to clip into, it might be another candidate to hang on that nail on the shed wall!

I've just bought a "new" bike, and with it there is a box of "unknowns" which may or may not have anything to do with the bike. Always a challenge!

Leon

Hello everyone I do have a MKII carb (1 1/8”) fitted on my 148cc XIIC engine and do have several centre pieces as option.

I do have 2, 3 and 4 (smallest).

Does anybody knows the internal diameter of these centre pieces?

Thanks!

Most likely cause of jamming is burred first tooth on the starter quadrant .......first meshing tooth should have a sharp point .....when it gets burred ,the traditional cure was to grind it off and sharpen the next tooth...........ditto the mainshaft ratchet gear ...it should have pointed teeth ..........I d also add ,you never stab at the pedal,mesh the gears first before applying pressure ...........The 1956 on  AMC box has the Norton style kickstart with a sprag engaging an internal rack ......reliable and near abuse proof.

Or is it timed on the compression stroke?