Another Eng/Frame query

[tomtit]

Done a search of the site and read the post by Chicago in regards to frame and engine numbers with some really useful info from Brian about the BSA numbering system which leads me to my quandary.

The frame number on my plunger A10GF is: ZA7R55* and looking at the BSAOC website states it's a '49 A7 frame and I'm assuming the "R" stands for rigid even though it's a plunger frame ?.
Engine number ZA10 1095* I think makes it a "51 A10 engine. When buying the bike I was told it was a 1950 but all I got was a receipt and a Haynes manual with no other paperwork.

The bike was bought by the previous owner from a guy in Goulbourn NSW  so wondering if anyone on the forum comes from that neck of the woods or maybe knew the owner or bike, just a thought anyway I'm off to the bank today to get a cheque made out for the BSAOC and get a cert for the bike.

Any help on this would be very welcome 

Tom

[Brian]

Hopefully a BSAOC certificate will clear up just what you have, but then again it may not !

Going by the information I have engine ZA10 1095* is indeed a 1951 engine.

Frame number ZA7R 55* is from 1949.

As you have a plunger rear section on a rigid front I would guess that the bike has had the original front section damaged at some stage in its life and its been replaced with the existing one. The plunger and rigid front frame sections are the same except the numbers stamped on them. If you really want to be fussy you could try and find a '51 front frame section.

[tomtit]

Thanks Brian, you are a fountain of knowledge. I had a sneaky feeling the frame may have been bastardized but wasn't sure if a rigid and plunger could be coupled together.

I suppose a '49 frame and '51 engine = '50 bike in someone's logic.

Tom

[Beezageezauk]

Hi Tom,

Yes, as Brian stated, the rear end of a rigid frame can be unbolted and replaced with the rear end of a plunger frame.  And vice versa of course.  So that will probably answer your frame question.

The single cylinder models certainly can because I know a guy who did exactly that some years ago.  The single cylinder plunger frames have a "S" suffix.

Beezageezauk.