Honda-SOHC

Just thought I would update any 350/4 owners about the problem I've been having with the leaking fuel tap.  I thought I'd tried everything - except for find a NOS tap, which are unavailable from the normal sources both here and abroad.  I had obviously replaced the lever seal and even refaced the lever, plus added a thin shim under the clamp plate - it still dribbled fuel - enough to compromise the float needle valves (all new Keyster items) and pee fuel all over the floor of the workshop overnight.  Enough was enough the other day after a lovely ride out, I turned off the fuel about half a mile from home and the following day it had filled up the chambers (with the tap still turned off) and then dumped a good pint or two out through the overflow pipes.
I realise that I still have issues with the float needle valves, but I needed to sort the tap pronto.
I drained the remaining fuel and removed the tank.  On removing the tap from the tank (it's different from the 400/4 tap) I checked the washers under the screw heads and found one was swelled and split.  These were new when I restored the bike but I think this bio-shite fuel might have taken its toll on them. 
It's a peculiar set up, so the screws holding the tap to the tank were passing fuel into the small filter bowl and then straight along the pipe to the carbs. There were no external leaks around the tap.
I was loathe to just replace the washers with originals, so I annealed a couple of new copper washers and put those under the heads of the screws with a blob of Hylomar as insurance.
Reassembled and filled with fuel - hey presto, no dribbles!
Strangely enough the carb floats have also settled down as mentioned by Ash in another post.  Even with the tap on and left standing - no problems.
I think draining the bowls allows so much angle on the floats that they might leak a time or two as there is a lot of sideways force as they come up to position, but at least that appears to settle down eventually.