Frame no RA 1383 ( not sure about the "R"

[Alan]

I have a frame stamped RA 1383...looks similar to my B29 frame but about twice as heavy ( probably due a relaxation of the UK excise laws in the 20's that penalised weight).....what bike would this frame be from...  ??? Just checked again
and first letter unclear so might not be an R..could be an "F"  ...not sure...

Also querying the date/type of a crankcase marked ER592 and at 90 deg to this stamped V2 ( this time the "R" is quite clear)

Ta Alan..
 

[oil baron]

Hi Alan

The frame number should read FA it was the prefix used for the 1930 H3 & 1931 B31 350 cc side valve,  The engine number FR is consistent with this model, my own 1930 H3 has frame FA 553, engine no. ER 399.  The H3 was equipped with footboards, heavier square edged flywheel and chromed petrol tank. I assume the B31 was similarly equipped.

[David Lawrence]

Hi Alan,
With regard to the frame and engine number.
The frame is almost certainly a B31 in which case the "F" is correct, quite a late number. Regarding the engine number most of the engines designated with the ER are listed as B31 but there does seem to be a bit of confusion regarding H and L 3 models all appear to be fitted into the FA (B31) frames. I will ask Len our registrar for a more knowledgable input and one of us will post a reply shortly.... unless of course somebody out there knows better!!!
I guess the weight limit may have had something to do with the heavier frame as you mention the weight tax advantage was removed by 1929. Or maybe they were using the same material as the much heavier S6, always looking to save money!
As an aside if you have the gearbox it should have a RG/ designation some with a "E" others "C"
I have no idea about the V2 but again if any info turns up will let you know.
Dave.

[Doug]

"V2" seems the turn up on many crankcases of different models during the late twenties and early thirties. Is it a smaller size stamp than the engine serial code? My assumption was it is some sort of inspection stamp, though it is not on every engine.

-Doug

[Alan]

Doug...from a quick ruler measurement ( my micrometer has just departed this life), the engine ID is
about 0.1875 in and the V2 ( followed by the Douglas mark) is about 0.125 in...