HELP! Pocket bike problem

Around 2 years ago I bought a 49cc pocket bike from someone and it worked amazing. I don't know much about pocket bikes so I tried to make my first fuel mix and I didn't know that it must be a specific way, so I just mixed a random amount of 2-stroke oil with some fuel put it. Then i tried starting it and it worked and after a while the engine just stopped and i had to restart the bike. It kept going on like that for 2 days and then all of a sudden when you started it, you could hear a scraping/banging noise. After that i left the bike for a year (with the fuel line on the whole time) and i have recently started finding a solution. The grinding noise was gone, but the bike wouldn't run with the choke on or when you sat down on it. I have recently been looking online and i think it could be the clutch. Can anyone help me?