Wouldn't it be a rubber gromet? Isn't that where the wires/speedo cable come up thru the tank? Been a while since I've had mine off.
07 vstar 650 midnight custom
Ais disable, 4.5 inch risers, V&H cruzers, jetted with pods, viking saddlebags, Kuryakyn mini boards and memphis fats windshield, fuel solenoids deleted, star solo seat and 4 inch extensions. Boss audio sound system.