I looked at the barrels from my engine, the fins left impressions in my fingers when I pushed on the muffs so they must be the better quality ones.
They also give the visual impression of being sand cast.
I have pondered the possibility of popping the liners out of the muffs for inspection, but am I being paranoid? The liners appear to be new, they are unmarked & standard bore.
I once honed a barrel assembly for a friends Comet, until I felt the liner turn in the muff! I had scribed a line to indicate the oil hole. When I dropped the muff off in the oven I discovered 3 variable bore diameters, none were concentric with the others, & none were round! It was a one father/son owner bike which had reputedly never been apart previously so the muff boring was presumably factory done. I honed the muff true & nickel plated the liner to get the interference back & although the bike does not do big miles, has never been apart since to my knowledge.
Another interesting thing arose from that, while being helped with the reassembly by much more experienced Vincent experts, it was spotted that the cylinder oil hole was 180 degrees out! It was suggested, of course, that I had assembled it thus, but I pointed to my scribed index mark & so the conclusion was reached that it had been assembled from new with the oil hole on the wrong side & went back together like that again! Just to maintain originality of course!
I have seen pictures of CNC machined, from billet, muffs, are the skirts integral, ie, muff & cylinder one piece of material, with nikasil coating? As a long time Guzzi owner I am a fan of this idea.
When resurrecting a pair of cut cases originality is not a high priority, well non existent really.
The 2 major design criteria for this case rectification were;1, maintain factory dimensions & have enough structural integrity that the engine could be used in a "standard" Egli dimensioned frame or Vincent frame components, (no need for a Norton loop frame)
& 2, have an oil tight chain case with a "standard looking" cover over it.
Here is the result;