Any GoPed riders here?

Im building a Goped from a electric Razor E100 frame and a 49cc reed induction motor with a CV tranny attached. total gear reduction is around 14:1 (7:1 through trans and then a 2:1 final drive 24/48 tooth chain drive) Looking for some gearing options. I will run a 5.5 or 9.5 tire so the total circumfrence is about 17 or 28". with 14:1 at 8000 RPM thats about 8 or 15 mph. sounds kinda slow for a goped. should I run a 1:1 chain drive for a 7:1 final drive @ 17 or 30mph at 8000? I dont want to kill myself in the process, no rear brake yet, just friction bike style front. This motor has no markings on it, has a .55 inch carb on it. Dont know if its a 36/41/49cc but its brand new and starts with 1 pull choked and sounds like a 2 stroke chain saw revving it with no muffler. Raps fast! would love to make a little go cart with it. One issue is the final drive cog rotates CCW as you look at it so it has to be mounted behind the axle.