Is the outside diameter of the Vixen Ally fuel neck 1.75inches or is the thread diameter 1.75inch?
The 1.75" actually refers to the outside diameter of the Vixen Ally neck that you weld to the tank. The outside diameter of the male thread on the neck is 1.875", the outside diameter of the cap is 2.125".
Archived in: Newton flush fit fuel caps | Ally Fuel Caps2nd June 2014