hi neil
well built and although you say "thrown together from bits" i think not! beautiful peice of work though.
i've a photo which i can send to anyone who'll host it, it's simply 2 pieces of steel. the first is an inverted 'F' and the second - for the front is an inverted 'F' but with 3 prongs and not the two.
i'm thinking of making one that hasn't got the 90d corner but more like 70d so that from standing upright it can lay back.
what i wanted to ask you neil is this:
you want to hold the left case flat and fit the guts followed by the right case. then you want to fit the flywheel, gearbox sprocket, oil filter.
next you want to work in the left cover. well with the system i thought of you simply pull out a leg at a time and replace around the other side of the engine, lay it on it's back and off you go. that leaves the head upright or again laying on it's right.
i could do with 2 or 3 of them.
regards
Taffy