I am afraid that I only have a Haynes manual which does not describe the area that I am looking at on my daughters bike. It is the 1982 electric start version and there appears to be a breather tube running from a location under the transmission cover, adjacent to the starter motor to below and outside the cover, approx 6cm forward of the drain plug..

Firstly, what is the pipe (is it a breather for the transmission case)

Secondly, what may be the reason for the transmission fluid constantly leaking from the pipe when the bike is shut down? - I am certain that the leak is from the pipe and no adjacent gaskets or seals.

Sorry I don't know the bike in any detail. But if it is a gearbox vent and it's pushing out oil, the crank seal on the clutch side may have started to leak. It will do it when stoipped as the oil makes it's way slowly down the pipe.

Have you topped up the transmission case with oil ? as it sounds like a breather pipe. From memory of servicing the Passola I seem to remember there is no way of checking the level you just drain out the old oil and refill with the amount stamped on the transmisson case by the filler which I think is 600ml of 10w/40 oil. Tony.