Jr 80 questions

I have a 2000 SE Jr-80 dirtbike w/ a factory racing engine that is having some problems. First of all, Where can I find a manual? I have tried the internet and they dont have anything. Also, when i go and give it some throttle the RPMs go up but it sounds like the sparks arent catching very well. so if i give it a lot of gas it then makes a low pitch sound and stalls. What is going on and how do i fix it?