Give the chain a shot of WD-40, wipe it down, and then use any quality spray chain lube. After you get it clean, you may want to adjust it. "Loose" is not the way it's supposed to be. Your fuel valve, aka petcock does not have an off position as it's only open when the engine is running and making vacuum (or on Pri - see below).
On - valve closed with engine off, open with engine running.
Pri - prime, valve is forced open to allow fuel to flow without engine running. Used to prime the carbs if/when you run out of gas.
Res - reserve, draws fuel from a lower tube in the fuel tank. This position lets you get to a gas station when you run out of gas in On.

Without knowing these basics, I don't think you're ready for mods.