Thanks all, I am listening with interest.
To give you the whole picture, my bikes, lovingly shipped from UK 25 years ago, have remained at back of shed untouched. I cannot even recall what parts are there. I am very very slowly starting to work on them, and as budget is limited, I am working on the swinging arm bike, which is in pieces. I am building my dream A10, which is purely my quirky vision of the perfect A10, and has features from many models. I love the looks of the fully enclosed chaincase, (no matter how fiddly), deep valenced mudguards, and headlight cowl. I love the Ariel style hubs. I love the Type 6 carby. I dont like chrome, so the tank will be my own take on a nice BSA tank.
I havent even got a Haynes manual (left it in UK). So I look at this forum to refresh old knowlege and for new info. I am starting with the head and barrels. The forum is great. e.g. I have 2 alloy heads (I just like the look of the alloy head: unlike Muskrat, I am not a speed freak, and high performance isn't critical) One I have removed the white powdercoat from. Gasket remover did work, thanks bsa-bill) the other is exactly as described by 1660 bob in 2010, so now I have learnt about bronze thread inserts (which had worried me with my alloy heads). I still have to remove the siezed sparkplugs, about which there is another thread. I really appreciate the wealth of experience of forum members, and their willingness to share knowlege in the friendliest of fashions. I will get going on my barrels next, using the advise from you all.
Thanks again, Gavin