Not necessarily Jacob.
Very early models (i'm guessing here) possibly in the 2-3,000 numbers, maybe a bit less, probably did have a brass "trumpet" inlet. Mine has anyway and it's within the first 500 motors that were produced. Something that i've struggled with on my data sheets is accurate information, or worse still a distinct lack in certain areas. Details like this are worth spending the time on in my view. However i've recently started seeing a few SD's well into the 8-9 000's with a brass trumpet too. I'm sure Hugo will figure it all out in time
(don't worry Hugz i haven't forgotten about you, just a tad busy this end)
Going by my slightly later paperwork it seems that as and when this brass "trumpet" was no longer available the alternative part would have been what we see on countless thousands of post war102's. No choke, cast aluminium up draught with SEAGULL. Paperwork actually shows me as much with any revisions. Exactly how many SD's were made with a "trumpet" is yet to be discovered.
It could be that ALL the SD's originally came with a "trumpet", although it's not unusual to see one with a cast aluminium cowl fitted to it either.
Your's being a fairly high number i would leave as is for now.
What do your pictures in the manual show you? Brass or aluminium?
Might be worth double checking the carb numbers as well to see if it's had a "swap" at some point.
You're looking for 46 A/3A stamped into the carb body somewhere. This should be (i hope) the correct period carb for your SD. If it's got something other than 46 a/3a it's a later post war carb which might possibly be connected with the different inlet cowl that yours is currently wearing. Now, this is where things get a bit tricky.
Early on in production it seems there was a brass version of the type 46 Amal. This brass carb/float bowl & bowl cover, along with the brass "trumpet" i believe is what was produced on the earliest models. It's also easy to assume that every SD that was made might have had a brass carb when it was packed inside its packing crate.As yet we don't know for sure. Some do and some don't. There's too few what can be called "truly untouched original" SD's out there to draw any firm conclusions from. As production moves along i think these brass carbs are at some point superseded by the aluminium versions, but as with a lot of things i haven't been able to verify much of this. According to the '62 paperwork the diagrams very clearly show a brass carb which is quite different in its appearance to the ally carbs BUT with an alloy inlet cowling just to add some confusion. As with most things, the more we look the more we find out.
I shall ask the question to my contacts in the MOD about publishing and diagrams etc. to see how we can proceed with this. But for now i would hold off. Tempting though it is to show some new information on here, you never know if there's some hidden clause we don't know about yet.
It can be a minefield when it comes to copyrights, especially when it's not your own to freely publish at will. Tread carefully is all i'm saying.
Jon
