cant go above 40

[iMoon1221]

So iv taken the interstate on my gz plenty of times but its usually a shortride on the interstate . The otherday i decided to go a bit longer. I was going70 -75 for 15-20 min then my bike started slowing downrandomly and i coukdnt speedup. I got off, looked at my bike. I rode it the reat of the way to my destination (no choice). On the ride the bike ran but at high rpms. It took alot of throttle to get it going and wouldnt go fasterthan fourty mph. I checked my oil and it wasflooded with gas. I just changed the,oil and am still having the same problem. And tips?

Oh. And my car just broke down too so i washoping to rely in my gz