GY6 149cc Scooter Won't Turn Over

[hominid4]

Hello. I adjusted the valve on my GY6 149cc scooter, and now it won't turn over. When I try, it will attempt to turn over but then it stops, like it's being stopped by something with resistance. And when I try to kickstart it, it's hard to push down due to resistance. If I take the spark plug out it the kickstart is easy with no resistance, and the electric start does better but still seems like it's having to struggle to turn over.

When adjusting the valves, I turned the camshaft to the T mark, the big hole was on top, I only had to adjust the exhaust, it was too tight, put it back together, and now this is happening. Didn't do any other work on it.

It's about a year old, with around 500 miles on it.

Would anyone have a suggestion what may be causing that? Thanks!