I had the same problem, my chain wedged itself into my spokes. This told me that my sprocket was too far out. my sprocket is sorta concave so i flipped it around to get it linear with what the engine wants to do.
I was only off maybe 1/8" and it was disasterous. sight down the chain to make sure it's linear
I am building my first bike. I am having trouble putting the chain on. When I turn the clutch lever, the small sprocket that the chain is suppose to go on won't turn. Is this sprocket supposed to turn with only hand pressure when the clutch is engaged?