OK, the negotiations aren't going very well. That is weekend of my wifes 40th birthday and she wants us to spend it with her parents.
That's understandable. Hope you have a good party!
Given that, any chance you can tell me where the air leak is likely to be Roy, please?
Well if the pipe joints, one way valve, and reservoir are all O.K. that only leaves two places. If you have ordered a new vacuum operating valve, that is one of them, because I would say it is leaking from the exhaust port. On old units the spring and/or clip gets rusty and weak and often leaks. If it is quiet, put your ear near it and you may hear it. The other place is the double acting servo itself. By blocking off the servo entirely you can check if that is a problem.
Sorry to disagree Anders but this valve can be stripped and overhauled, as I have done quite a few, but when stripping you have to be careful to note all part positions as there are parts that must go back in the correct way otherwise things will not work. If you remove the exhaust port clip and spring you must note the exact position first as the pressure must not be too much or too little. Also you must not lubricate anything with oil which will cause it to stick very quickly. The rubbers must be clean and dry and a little talcom powder makes a for good lubrication!
Roy
P.S. For the curious, the carbs. were too weak at the top end, and via email (not the ideal way!) I have been trying to get it better set up. It is now a little rich so the original air correctors which he put back to see how it ran with those, need to be opened up slightly.