Hi there – as no one else has replied, I’ll try and say something to help, though I’m no expert: but surely this is part of the point of this website. I should say I’m no great shakes as a mechanic either, but with help, I seem to be lucky to keep them going. Fingers crossed for tomorrow.
I would suggest – as everyone else here does, righty – that you don’t rush into a purchase of a bike you don’t know, or a bike no one you know, knows (God, I never thought I’d be misquoting Don Rumsfeld).
Vincent twins can soak up a lot of cash to get right. And time, too, if they require work. Find one, if you can, that you’ve seen run – one that has been with one owner for a good few years, and has done some miles. The bikes are around. If they are in good fettle, each model is wonderful. I’ve been lucky to ride most models. If not, each one can be a pig – there’s a lot on a Vincent to get slightly wrong, spoiling the whole package.
Shiny paint, recently restored, a wad of bills showing what someone needs to make back on the bike – these are not, in my humble opinion, the beginning of a long lasting friendship with a wonderful motorcycle. If not the best ever.
Happy to try and help further if you PM me. I can’t find the Cheffins bike; the one at Bonhams looks OK, but the tank seems to sitting rather low. A good Rapide, however, is no way 15 – 20% less of a bike than a Shadow… who does 120mph on a Vincent today? Did they ever? Answers on a post card.