I'm presently having fun setting up a pair of 28mm Amal Mk2's (they came with the bike) on my Rapide and one of the first things I wanted to get right was the Fuel height. The general recommendation for all Amals seems to be to set the front of the Float (opposite the hinge end) 2mm below the rim of the Float bowl with the needle just closed. Its OK as a rough guide but there is a lot of give and play in the float and spindle, plus I don't fancy heating and tapping the needle housing up and down too much and causing damage. To try and get it spot on I've bought a spare Drain plug that I'm going to drill through and connect a clear plastic tube (manometer) so I can see the actual height from outside. The next problem was finding out what the correct level should be, after much searching I found it on the following web site: http://www.oldbritts.com/amal_tun.html
They quoted from the Amal design engineer that the fuel level should be between 4.3 and 6.1mm (.17 -.24" for those who bought their Vincents new) below the top of the bowl.
So now I've got the level I will shortly be trying it out to see if its correct or not, remembering to check all four sides as its the height in the middle that's important.
I've posted this in the hope it may be useful and to see if anyone else has already tried this out.
They quoted from the Amal design engineer that the fuel level should be between 4.3 and 6.1mm (.17 -.24" for those who bought their Vincents new) below the top of the bowl.
So now I've got the level I will shortly be trying it out to see if its correct or not, remembering to check all four sides as its the height in the middle that's important.
I've posted this in the hope it may be useful and to see if anyone else has already tried this out.