AJS & Matchless Owners Club

Hi everyone, I am in the process of rebuilding a 1946 Matchless 500 from a basket case I got a few years ago and found there are no dots at all on the cam gears. Would anyone know the best way to find these e.g.the position in relation to cam lobe or some other way. I am in Melbourne Australia and all of the stores and mechanics for these types of bikes are sadly gone
Any help would be appreciated.
Thanks, Steve.

Steve

There were several threads on this topic over the years. I don't know if you can use the search facility if you are not a member; it's well worth joining.

Johnny B

are there numbers rather than dots ?

Inlet valve timing :—
Inlet valve opens 32° before top dead centre.
Inlet valve closes 63° after bottom dead centre.
Exhaust valve timing :—
Exhaust valve opens 65° before bottom dead centre.
Exhaust valve closes 30° after top dead centre.
When checking the valve timing the tappet clearances must be set to .016" so that the
tappets may be well clear of the quietening curves of the camshafts.


http://archives.jampot.dk/book/Owners_m ... Manual.pdf

The method of cam marking has been altered since 1945. The year of
manufacture and type of marking used are as follows:-
1945-48—Cams are marked with a dot. The pinion has a line on the
outside face midway in the keyway slot.
1949-51 —Cams are marked one and two for use on both Matchless and
AJS engines. Number one marks are for Matchless engines, number two for
AJS.
1952-53 (Valve Lift 0.326 in.)-Marking similar to 1950-51 models, with the
exception of assembling, when number two marks are used for both
Matchless and AJS models inlet and exhaust. (Both models have magneto
in front of cylinder at this date.)
1954-55 (Valve Lift 0.362 in.)-Cams are of the high-lift type (marked HL).
Additional figure number three is used for setting Inlet timing on the 350-cc
model only. Use number two marks for the 350-cc exhaust and for both
valves of the 500-cc model.
1956-58 (Valve Lift 0.362 in.)-Number three used for the 350-cc inlet,
number two for the 500-cc inlet and number one for the 350-cc and 500-cc
exhaust
Note—The latest type camshafts do not use a keyed shaft to drive the
magneto. If a keyway is not visible in the cam wheel use No.1 mark for the
exhaust-cam setting, before 1956-57

This discussion really helped ..!!

Thanks for the replies guys, there are no marks , numbers or letters on cams at all, looking for a guide as to where they should be e.g I line with top of cam lobe or bottom or something of that nature.
Thanks for any advice.

g80csp11 wrote: ↑Tue Mar 19, 2019 10:32 pm
Note........If a keyway is not visible in the cam wheel use No.1 mark for the
exhaust-cam setting, before 1956-57

Now that's interesting..I've just been struggling to set up a pair of cams sourced from different engines, which consistently produced hopelessly mismatched phases when set up with book settings. After ignoring the dots and just using a timing wheel I found the best set up for this 350, then checked where the dots had landed and....drumroll...."3" for inlet and "1" for exhaust...just as mentioned above.

I'd totally missed that important nugget in any other research, may I ask the source?

This should help, it gives directions on how to proceed whether there are dots or not so you can at least get the engine running. Hope it's attached!"

Hope it helps.

Johnny B

It is, and thanks JB