Valve Timing 47 Matchless G80 L - 3 dots - WTF!

[dhgarske]

Both my valve cogs have 3 dots and 2 numbers - see attached image
SOoooooo confused right now.
I can not find any documentation that shows the same dot configuration as what is on my engine.

From what I have read - it seems "Joining the Dots" article might be best... as in dot 2 (the middle one) is for the '47 G80 L 500.

Anyone else seen this configuration?

This bike was a "barn find" and I know it became a bit of a Frankenstein bike as the farmer just fixed things with whatever he could find.
The engine number says its a G80 L... but the points are at the front - like the AJS 18.
see here https://goo.gl/photos/NbS9Jy69dmy6Gwo56 for images of the bike when found and the pile of parts it is now.

Any help... greatly appreciated. And if you are in Sydney Australia - please visit me and HELP!

[Rob Harknett]

http://archives.jampot.dk/book/Workshop ... dition.pdf
The bike is made of different years AJS & Matchless. 1947 /1954 clearly seen. So have a look in a later manual where you will see changes over a period of time. Like timing, both cogs having two dots, in 54 the inlet got 3, and in 56/57 both had 3. You may find some clues if you compare various Joining of dots. Using this book and the article you have found. The book is AJS as your 47 G80 engine seem's to have 1938 / 54 AJS timing cases. 1938 ??? That may surprise you. But, the outer cover was introduced in 1938 on the 250 model 22 upwards singles. You will see the old pt. no. cast inside the cover. 38-22-E???

[spookefoote1956]

I concur that I used this very method yesterday. I also have a bitsa and used number 2 as my guide. Why? because I lined up the central timing cog with the centre of the inlet cam bush and then put the cam in. There is a small wall within the casting that will not allow the cam to go in in line otherwise. Then I rotated the timing cog to the exhaust bush and put the cam in lining up number two with the dot. Again it can not pass the cast wall any other way. Voila!

[dhgarske]

http://archives.jampot.dk/book/Workshop ... dition.pdf
The bike is made of different years AJS & Matchless. 1947 /1954 clearly seen. So have a look in a later manual where you will see changes over a period of time. Like timing, both cogs having two dots, in 54 the inlet got 3, and in 56/57 both had 3. You may find some clues if you compare various Joining of dots. Using this book and the article you have found. The book is AJS as your 47 G80 engine seem's to have 1938 / 54 AJS timing cases. 1938 ??? That may surprise you. But, the outer cover was introduced in 1938 on the 250 model 22 upwards singles. You will see the old pt. no. cast inside the cover. 38-22-E???

Wow! She really is a "bitsa" isn't she! clearly this was repaired with anything that was around. I appreciate the info. Thank you