Gas Preservative Contradition . . . ?

[norsseman]

Stabil is the gas preservative I use and the directions say to top of the
tank to the very tip top, but Kawasaki says not fill the tank up to the
top, and to only fill the tank to about 1 inch below the top.

What harm does it do to fill the tank up to the very tip top?

My bike is a Kawasaki Vulcan 750, 06'

[hot_shoe_cv]

Stabil is the gas preservative I use and the directions say to top of the
tank to the very tip top, but Kawasaki says not fill the tank up to the
top, and to only fill the tank to about 1 inch below the top.

What harm does it do to fill the tank up to the very tip top?

My bike is a Kawasaki Vulcan 750, 06'

Filling to the very top leaves no room for the fuel to expand when warming up to ambient temp. thereby overflowing the tank & damaging paint or decals if done often & not rinsed off, Plus could be a hazard if the engine was hot and fuel flowed onto the cylinders.