I put a 80cc engine on my schwinn stingray it looks great. I have a slight or severe problem you could call it. It starts up fine no slipping etc starts like a champ. When i get her going and give some gas it acts like the clutch isit catching and revs high with alot of vibration. However if i slightly turn the throttle it will catch and i can go 10mph for about a minute or 50 seconds i rev it up and it starts to shake/vibrate a lot and not catch so i mess with the throttle untill it catches. Along with that its leaking oil from somewhere. So any ideas? I was thinking about checking the gears/clutch on the right side to see if anything is wrong but since it is starting and pedaling fine I'm not to sure. While im riding i get blowback from the oil too, my dad jokingly said you look like your riding a old Harley lol.