No.
plastic renew won't take the yellow out of your white tank, most of that is from the fuel/oil mix vapours leaching through the plastic over a number of years, the discolouring usually goes through the entire thickness of the plastic.
The final glossy layer of the renew is just a coating (similar to armour all, but a bit tougher) and washes off when it comes in contact with fuel.
It does a good job of the rest of the plastic on the bike though.....but's a lot of hard work. It's fairly expensive and is sometimes easier just to buy some new plastics if avaliable.
For the tank, easiest way to get it back white is a sticker kit.
What bike is it?