My continued fuel Mod consists of the relocation of the sight gauge. I decided to put it in-between the seats as suggested by Alan Yearly in the USA at Custom Flight Creations. An Aluminium plate is shaped to fit the area fixed without drilling the fuel tank. The site tube is threaded from the out let to the top and over the top of the fuel tank.
This his description: The Europa vent system puts the vents on the top of the aircraft just aft of the lowest area of pressure. A full tank with a roll to the right and you have fuel streaming aft through the vents. The low pressure area on the top of the aircraft pulls the sight gauge from its true value at low speeds, and at high speeds makes it read low. So, why not move the vent to the bottom, keep the aircraft clean, and any over fill will drain the fuel to the ground. Make the vent as the plans call for and just put it on the bottom. I put it on the forward side of the rear bulkhead for a tri-gear and on one of the baggage bay floor supports for a monowheel. We make one vent tube normally, but you can use two. Just don't hook it directly to the sight gauge. You must us an FS09 for your vent fitting. Vent the sight gauge to the aluminum 5/16 outlet and the bottom of the site tube to the Tee off the bottom main drain line. Never the feed line. Attach the vent line to the brass 5/16 nipple of the FS09 (the 5/16 nipple is attached to a 1/4 inch tube copper pipe as per the extended range tank setup) then to a Tee located near the top of the filler neck, then over the top of the neck and down through the floor of the baggage bay or into the tri-gear support to where you put the vent. Finally, consider putting the sight