headstock gusset

[RDfella]

Been wondering for a while about these gussets. The early ones came halfway up the headstock tube, whereas later ones almost fully covered the tube. But at what frame number did they change? Literature says around 1960, yet two '62 frames I have both possess the shorter version. Anyone have a definitive answer?

[limeyrob]

Not an answer but some more info.  I went to buy an bitza A10 off e-bay.  I walked away.  The frame had the gusset cut off and no number.  I queried this and the seller told me that he was converting the bike to an RGS replica and "you can buy the deeper gussets".  I see some frames for sale emphasize the deeper gusset and 4 front lugs.   But there is a view that makes sense to me that by the late 60's all factory replacement frames came with the deeper lug and 4 lugs regardless of what model it was.  Why stock different frames.
My '59 frame is low gusset and 2 forged lugs.

[muskrat]

G'day RD.
From what I can gather the long gusset started with the GA7 numbered bikes of 1960. 
Cheers

[trevinoz]

I think that you will find that the gusset changed in 1961.

[muskrat]

^^^^ 

[JulianS]

The high gusset was introduced for the 1961 season models, around August/September 1960 and around frame GA7 11101. Billed as an improved frame by BSA in the 1961 USA brochure below..

The 4 front lug frames were introduced in spring of 1962.

[limeyrob]

Love the 140 mph speedo. We all know the higher the speedo the faster the bike