Be really careful if you decide to line the inside if your tank. If you have ever run pre mix then you have oil in there which will make adhesion a challenge. Most of the companies that offer tank lining products will not guarantee their product if the tank used premix.

The second issue with these products is that most of them will not tolerate ethanol based fuels. Even E85 will break them down. It is common in the aircraft industry to use sloshing compound. Most of these products will stand up to Avgas, but will break down over time from ethanol. There is one company that makes a product that will not break down when exposed to pure ethanol. I haven't used this product so can't vouch for it. But when i spoke to them they claimed to have a steel paint can in their shop lined with their product and filled with ethanol for over a year with no breakdown of the material. PM me if you want the link to their website.

The two part epoxies will soften over time and will break down from ethanol.

Over 15 years ago i coated my BMW R90/S tank with sloshing compound and haven't had a problem. Two years ago my dad coated his BMW R29 tank with a 2 part epoxy and it is now starting to soften and lift. I recently had some crud in my NSR carbs and spent time researching products. In the end i put a filter on my bike as i do not know if anyone ever ran premix in it. The filter works fine and is cheap to replace.

Remember this, once you go down the path there is no turning back. If the prep work is not done right or you used the wrong product, you will ruin your tank.