Kloner

Don't know what's all done except for pipes, bore, and cool head the guy i got it from was dummy he aint know shit

What would be wrong with it any advice needed

I had got a banshee but I did fresh o rings for the cool head and put it back together and it is leaking from somewhere I don't know where but before it was the plug in the back of the engine on top but I don't think it's leaking again it wouldnt hurt to look but my shee starts and when it do it idles too high and back fires a little bit