Thanks to all your fantasic help and advice the engine now looks like this>>>>>
I have already cleaned all the parts, yuk,,, and have a list of parts required i.e, new crancase oil seal, when I change the studs over to bolts, and the seal is a bit iffy anyway.. New crancase breather washer, any ideas what size I need, engine is a 51 model if that helps, new clutch springs, 3 x clutch adjusting nuts that had worked loose and worn away, posssibly the clutch plates, not yet checked the dimesions and a couple of aluminium repairs to the crancase (not me i mighnt add).
Once again thanks for all the fantastic advice I would really be lost without this forum,.
Oh yes one final question, any suggestions on what I should change as a matter of course or would concider updating whilst it is all apart?