Tank Staining Materials in Fuel?

[Pat Burroughs]

I have always run natural color tanks in my bikes. I ran pump fuel in my '96, then switched to race fuel on my '98 and '01. The natural color tank discolored (yellowed) on the '96 and did not on the '98 or '01. Same premix used on all bikes. I can only conclude that there's something in pump gas that causes the tank to yellow. Anyone have a clue as to what specifically it is in the pump gas that does this? Oxygenation? Lack of lead? Space-age polymers? Sparkling drop of retsin?

 

[Mr. Clean]

Everything is the same except the year model of the bikes. I think the plastic formula may be better on the latter two. I think I think they added two,two, two drops of retsin in the later years.

Bobsey twins.