[The 26incher]

Hey guys! Well I just finished putting a 140cc(at least I think it's a 140?) engine in my CT70. Runs great(so far)! Engine feels like it has alot of power and kicking it is just like a big bike! My problem is gearing. I'm thinking about running 16/31. How does that sound? Right now I have the stock CT70H rear sprocket on it and first gear is almost not there. I can start off in 2nd gear no problem and it pulls like a rapped ape into 4th. I want top end. I have my Z50(8" wheels) geared 14/26. It has an older "Square"(again, at least that's what I think) big valve head Lifan 125cc engine in it and it tops out @ 55mph. I don't think I can get any more MPH's out of it. 55mph on a stock 1973 Z50 is almost scary! I want 70+ MPH out of the CT! The CT has 10" wheels and it's quite a bit longer then the Z50 so I think I can handle more speed(brakes on the other hand is another story). So back to the question, do you guys think I can get 70+ from a box stock 140cc with 16/31 gears? Could 16/31 be too tall? I'm @ sea level and I'm 175lbs. Let a brother know what you think. Thanks, Jason