Welcome to MBc, Jonathan. I have posted this to various sites. The nuts, bolts, and studs that come with most China kits are junk. The first thing I do is round them all up and throw them in the scrap bucket. Then I go down to the local hardware and replace them with Grade 8's..Stainless Steel if near salt water. There are only a few, and they will not 'break the bank' to replace them all.
Second, I take a good look at the chain tensioner wheel and bracket. If it looks cheap and flimsier, I would replace it right off the bat before it has a chance to twist loose and wind itself into the spokes, or, anchor one end of the chain while the rest of it whips around wreaking havoc with you and the rest of the bike until the engine stops!