Or go buy a modern "retro" styled Honda
Okay, okay. I think Trevor was just being tongue-in-cheek humorous with this comment about the Honda (one could do worse). I will slightly disagree with Trevor about the reason for the breather (without setting myself up as some ultimate expert). I don't beleive it was "designed" to drip oil, but was, indeed "designed" to vent the crankcase which contains mistified oil (as opposed to our forum of mystified oilers). By my reckoning, for my '55 swingarm, the venting occurs 90 deg ATDC, which should represent close to neutral crankcase pressure. Also by my reckoning, the only reason for the breather is to keep the crankcase near one atmosphere, so that oil can be pumped in and out with respect to the one atmosphere sitting on top of the oil in the tank.
With regard to the "tradition" of drippy British bikes, great admiration for your success in the area of driplessness. However, while I might be less fastidious or peccadillocious about solving the dripping riddle, I light-heartedly take exception to ascribing my drips to being "hamfisted," "impecunious" or "incompetent. As for Bert Hopwood, I think the existence of the tube says that BSA expected some drips but they wanted them on the shed floor instead of the bike.
Richard L.