Topic: new fuel tap leaks!

[petercb750]

Gurus - I have installed a brand new genuine Honda fuel tap on to my 1972 K2 750, and in the closed position it still leaks fuel through the brass outlets - it started off as a dribble, and I've got it to just a steady drip now. I tried another new washer (the little round one with 4 holes) but that only helped very marginally, and have even filed off the little lug on the front plate that stops the tap turning past the horizontal, so that I can turn it just a bit further, in case the slot on the inside of the tap was not going quite past the "off" hole, and this did help more, but still I have a slow drip when turned off. 
This is probably not a huge problem in itself, but it was enough to flood #4 carbie and spew fuel out the overflow overnight, so I know I've got a small problem with that float valve, but it doesn't detract from the inability to turn off the tap fully. My trusty mechanic and I have spent ages pulling it apart and swapping bits over etc with no success.
Anybody got any suggestions?  Is this common and should I just put up with it and fix the float valve?
Thanks in anticipation.......
Peter.

[750goes]

1... fix the float valve - it will stop the garage stinking up with fuel vapour...

2... investigate that petcock - it seems odd that it continues to leak if it was rebult with the correct kit .........is there a flat washer that should be concave or convex that goes just under the outside ring ?? I know it is not supposed to be flat - could that have been put around the wrong way or flattened out by mistake.......??

 

[petercb750]

Agree - must fix the float valve!! Bike is actually parked inside (!) while the new garage is veing built, so the house stinks of fuel, except I have now resorted to clamping the fuel lines when I park it inside, which has helped heaps of course - much to the good woman's relief!! 

And it wasn't just a kit I got, it was an entire brand new complete tap!! Which is even more annoying!
I tried to fix my old tap with a kit, also without success, so went all out and bought the real mccoy. The flat washer was in there and all LOOKS correct - got me beat...........

[Kevin400F]

Any chance the leakage could be due to the sealing washers on the mounting screws?  (Item 25 on the attached pic.)

[petercb750]

my physics and mechanical skills aint too good, but if those washers were crook wouldn't they only allow fuel to leak into the bowl at the base, which then couldn't find it's way past the 4 holed washer if it was turning off properly?
But you've got me thinking Kevin........

[Kevin400F]

I believe the fuel goes from the tank past the four-hole washer valve, into the bowl, then out to the fuel lines.  I'm pretty sure the design is such the sediment bowl can be removed for cleaning when the fuel valve is in the "off" position.   If so, the bowl is the last "link in the chain", and seepage past the mounting screws direct from the tank into the bowl would give the symptoms you describe.

Cheers,

Kevin

[petercb750]

Ah ha - you've educated me on how the tap actually works Kevin -  It finally makes sense now. Will investigate - and thanks for getting back to me so quick.
I did know you can take the bowl off with the tap turned off - I've done it for cleaning the filter heaps of times - should have clicked on that myself, and then worked out the direction of flow from that. One of the probelms of more frequent "seniors moments". 
Many thanks,
Peter.

[bryanj]

Those washers are "hard fibre" washers and if they leak YES fuel will flow though