My bitsa G3?

[rastuss51]

Hi everyone.
I have just bought myself a 1951 Matchie 350cc G3LS (at least that's what it said in the advert. Not knowing a great deal about them - despite lots of research on this site and elsewhere - I have come to the conclusion that it's a bit of an enigma. The V5 (and pot) states Engine Number: 50s/18/14622 and Frame No: BR851. After reading Roy Bacon's excellent book 'Matchless & AJS (All Post War Road Singles & Twins) Restoration, I THINK I have the following: 1950 Sprung/AJS Model 18/ Pot No:14622. This gives my Matchie a 1950 AJS 500cc engine - not a 350cc! Furthermore, the Frame No: BR851 never existed and probably should read 88851, which is in the correct range for a 9/51 - 9/52 350cc Matchie heavyweight single frame.
Has anyone got any thoughts onb the above, please?I will strip the bike down a bit to identify the correct frame number (stamped under a lot of black paint under the o/s seat lug).
Thanks in anticipation.

[Eamonn]

Take a look at the various dating services the club offers under the Club menu heading called "Machine Dating".

You'll be able to get detailed answers to your questions regarding the heritage of the frame and engine number !

[wilko]

It might have 350 topend on 500 cases.

[rastuss51]

I thought the top ends for the 350 and 500's were the same?

[SPRIDDLER]

The H/Weight 500 barrel has a larger bore than the 350. Both have the same stroke and stud layout therefore 350 and 500 barrels fit on the same c/case (with the appropriate pistons, cylinder head, carb, zorst etc).
It was common to fit a 500 barrel, head etc onto a 350 c/case to increase the capacity of what was originally a 350.
You have a 500 c/case (18) but it could have either a 350 or 500 barrel fitted onto it.

[rastuss51]

THANKS FOR THAT