68 BSA carbs question

[oneuptom]

The "New guy. 68 BSA" thread got me wondering if maybe I could find the definitive answer here.

I too have a 68 BSA, a Spitfire, all stock... All the "experts" so far have said the monoblocs on it aren't original. The guy who sold it to me isn't into bikes but said his dad bought it new and didn't remember him ever changing the carbs

Edit: http://classicenglishbikes.com/tech_file/bsa.html#1968

I tried searching previous ownership in the past with no luck! My title lists the bike as a 1968 A65SA1775_,(purposely left out the last number) but the above chart says a 1967 Spitfire should be a A65SA, the 1968 Spitfire A65SB?

Maybe that's why the monoblocs are on it, because it's really a 67?

But my BSA is badged a MKIV and has all the 68 signs like brakes, covers, etc and the title matches the stamped VIN

My only guess is the bike shipped with GP carbs but were changed out early on??

https://usedmotorcyclesforsalelist.com/04/29/1968-BSA-A65SA-Red-craigslist/

Evidence of another 1968 A65SA
Mine looks exactly like this one except for the carbs and the bars. Lower bars on mine

[TriNortchopz]

this also lists the SA as '67:

http://www.motobrit.com/motc2/mpages/tech/numbers/bsanumber.php

look at part numbers and references in the '67 factory parts book:

1967 BSA 500 Twin & 650 Twin

A50 - ROYAL STAR
A50 - WASP
A65 - LIGHTNING
A65 - HORNET
A65 - SPITFIRE MK II SPECIAL
A65 - THUNDERBOLT

https://partsbooks.britishonly.com/partsbooks/20-10306C.pdf

from here:

https://partsbooks.britishonly.com/#BSA650Twin

[oneuptom]

this also lists the SA as '67:

http://www.motobrit.com/motc2/mpages/tech/numbers/bsanumber.php

look at part numbers and references in the '67 factory parts book:

1967 BSA 500 Twin & 650 Twin

A50 - ROYAL STAR
A50 - WASP
A65 - LIGHTNING
A65 - HORNET
A65 - SPITFIRE MK II SPECIAL
A65 - THUNDERBOLT

https://partsbooks.britishonly.com/partsbooks/20-10306C.pdf

from here:
https://partsbooks.britishonly.com/#BSA650Twin

Thanks bud!

I'd be curious to know how high the Spitfire numbers went after this one. If it was one of the very very last ones is it possible they just threw parts at it? Dumb Yank will buy it anyway Regardless I'm not disappointing because a matched set of monoblocs has more value to me if I ever want to convert a 59 TR6 to dual carbs. I would imagine they're not super easy to find anymore

[GaryE]

What you have is a "hybrid" '68. It is all '68 model year including the frame & engine (which are both different than '67). The only difference is it has a '67 number. There were 468 "hybrids" built in late model year '68 (April/May/June). The reason for them is unproven. Tons of urban legends out there. Very long thread about the Hybrids and the "Y" machines on BritBike Forum. The jury is still out on 'what' 'when' 'where' 'why' about them.

As far as the carbs '68's came with 32mm concentrics, never monoblocs. Even the '67 Spitfires had concentrics. The '66 Spitfires had the GP2's.

[TriNortchopz]

...a matched set of monoblocs has more value to me if I ever want to convert a 59 TR6 to dual carbs.
I would imagine they're not super easy to find anymore."

Amal Monobloc Series

https://amalcarb.co.uk/monobloc-series.html