fuel pipe config

Hi, I just stripped and cleaned the carb on my 1972 DAX 6V ST70.

Unfortunately I did not mark which fuel feed pipe from the tank attaches to which input to the cock on the carb.

I can tell which pipe is tank and which is reserve easy enough but can't tell which one connects to which stub - front or back.

I've looked through my workshop manual - no help.

I don't want to find out the hard way!

...thanks for any advice offered.

I don't recall what way around it is but turn the tap to reserve and blow thought each stub, if air passes then that's the reserve.

duh! thanks...

...wish I'd thought of that.