Originally Posted by kamanya
I changed a bit of the plumbing on mine.
The vent and T piece didn’t work for me when the tanks are really full. If you have filled them really to the top the vent pipes because they do not loop high enough, then act as a siphon on the first application of the brakes, you then lose a litre or so. Even when not completely full and you brake, for that little time that the petrol is forward it vents out. Also the vent pipe from the "T" piece was too short as it drains to just forward of the radiator and when it does drain I can smell petrol badly.
So I changed it by buying quite a bit of piping to create a loop that runs to the highest point behind the light (it’s a tight fit). At the highest point I put the “T” piece. This pipe then runs back through the head stock and then between the left tank and the frame above the radiator and then down by the clutch slave.
The other thing I’ve done as a result of having to fill other bikes more than once is make it easier to do this.
The right hand tank runs directly to the fuel petcock instead of going to the left tank forward tap. This pipe has a “T” piece that runs to the pump. On the left hand forward tap I have a pipe that I use to tap from.
The beauty of this system is that breaking the left tank is not a show stopper – just turn off the petcock. Break the right hand tank turn off the right forward tap.
This system would not work on the 990’s because of the pump being in the tank.
I *think* I get what you are saying (and I appreciate the input helping me learn from your trial and error).
You don't have any photos of your plumbing job do you?