I am new to all this stuff. I am in the process of building and fabricating a drift trike... anyone have any tips of all? And a couple more questions I have a 5 hp briggs and stratton motor off a rototiller and was wondering if and how you run a aftermarket air filter on them? And the other question I have is the gas tank on it is full of rust. Its not rusted through but just really rusty. I already tried bbs and gas. It cleaned some of it out but it still has alot in there. Opinions?