I own a z-550 1982.I have just changed the diaphram in the fuel tap.But still when the bike have stand still for about 3-4 days, If i shake the bike a little there are fuel coming out from the hoses connected to the fuel bowls on the carburators.PLEASE ADWISE!!!!!

The fuel is coming from the overflow.Check the tap isn't on 'P' or PRIME.
Check that there is no crud in the float bowls that could jam the float needles.
You may need to check the float height and re-set it if necessary.

Just read your post - you need to be very careful with this sort of problem - get it fixed quick.
The reason is that you could get fuel leaking into your barrels and getting a hydraulic lock - and get a bent rod!
It could be that the O ring at the fuel tap is not seating properly?
The other issue is the needle valve may not be seating properly and shutting of gas as it should.
If the needle valve sticks - gas can flow when it should not - and this is NOT GOOD.
You could add a manual in line fuel tap - to be sure!