On my '63 122 with the B18 and dual SUHS6's I cannot seem to get the things to sync up at all. The rear carbs piston will not rise at the same rate or to the same height as the front carb. I have tried tuning them by adjusting the idle screws and the fuel mixture nuts, but it seems that the rear carb just doesn't have the vacuum it needs to raise the piston. Needless to say it is running like crap and is almost impossible to start, but after the engine reaches operating temprature it will start to runn okay with the rear piston still only rising 3/4 the height of the front with none of the responce of the front when i do the gas by hand.
The rear carb has the vacuum advance hose in it. could that be the culprit? I'm at a loss even where to start. If anyone could give me an idea of where and how to go about testing for the problem, please do. Thanx alot.