1949 twin carb Star twin rigid

[BSARoadRocket]

This is a shot in the dark but I'm buying what I believe is a 1949 long stroke Star Twin with the twin carb setup.   The bike is a completely dismantled  basket case but what caught my attention is that it has one of the last of the early twin rigid frames that is a bolt together frame  and it has a R in the VIN number for rigid rather than an S for spring frame.   All of the 1949 star twins I can find any info on have the bolt together plunger frame.   They are few and far between but I know a few Golden Flashes left the factory with rigid frames so I figure it is possible that a 1949 star twin with dual carbs could have left the factory with a rigid frame as well.    Is there anybody who has seen or heard of a 1949 Star Twin with a rigid frame and Dual Carbs?   I'm really curious to if any other rigid frame twin carb 1949 Star Twins have been known to exist.
Tim

[orabanda]

Well done Tim; you have an interesting machine.
Can't add to the information re dual carb rigid Star twin, but I do have a rigid A10.
Richard

[JulianS]

The Star Twin came with a plunger frame as standard.

The only way to check what you have is by a factory despatch book check which will tell you what it was when it left Birmingham. Quite possible that it has undergone an engine transplant inthe last 70years, many bikes have.

The early A10 was offered with either plunger or rigid frame on the UK market.

Below from the 1949 US speadsheet catalogue.

[Swarfcut]

 Thanks Julian.  Shows off the use of the rigid style of toolbox "The Triangle" on a Plunger Frame.

  The bolt up frame meant the same front for Rigid and Plunger, but maintained the flexibility of supply of the two different frame types at minimal cost.

 Tim   I reckon the new purchase combination would be  extremely rare, and more likely a mix'n match.

 If the Longstroke engine is completely dismantled, the Camshaft, Followers and Guides are somewhat rare, so I hope they are included. Inlet  cam follower guides are pressed in place into the crankcase, so are most likely present, but the centre guide for the paired exhaust cam followers comes free when the cases are split, so may be mislaid.

 The camshaft and followers are unique, more of a later A50/65 style with narrow lobes, and  prone to a higher rate of wear than the later engine which has an added oil dip trough and lower surface loading on the followers.

 Swarfy.