Hi,
Some great discussion glad it was not just me that struggled with these.
From the responses, looks like the Triumph method of using the Stat-o-seal (an evolution of the Dowty...) and a thin flat washer between the locknut and seal as per Triumph method is an accepted method, and the exact parts are listed on the feked site below. I dont think sealant is needed on the threads with this method..
Interestingly the feked site calls them Dowty but they look more like Stat-o-seal type and they cross reference to the Triumph part number mentioned earlier. If I am not mistaken the Stat-o-seal has a more o-ring style rubber which protudes and gives more squish when tightened:
Seals (Triumph part number 70-7351):
Dowty Washers for Fuel Tap 1/4" Rubber inner section Hole id 1/2" Used for fuel petrol tap seal, also tacho drive seal, and other uses across the range of bikes. OEM: 70-7351, E7351, 70-6961, E6961
www.feked.com
Flat washer (Triumph part number 83-0002):
Fuel Tap Steel Sealing Washer - 1/4" BSP Petrol Taps. Thin flat steel fuel tap washer locates between the Dowty washer and tap locknut to ensure a tight seal. OD: 7/8" (22.3mm). ID: 3/8" (9.8mm). Thickness: 0.03" (0.7mm). OEM: 83-0002, F10002
www.feked.com
Thanks for everyones help!
Regards,
Julian