well i got the bike pretty much done this morning and i went to take it for a ride but the chain keeps coming off. i think i might need an idler pulley. the engine is mounted to the seat post so i can tighten it by raising the seat, but then when i sit on it, it still loosens up a little bit, so i think that is my problem. just wondering what other people might think. also if you think it is the idler pulley, where is a good place to get them for pretty cheap cause i dont have much money right now, i just need to get it running. it doesn't have to be really high quality because im not going to ride 10 miles everyday. maybe just 10 miles a week for now, till i get a 4 stroke . thanks for any help. i guess at thatsdax it would cost about 24 bucks. i was just wondering if there is anywhere a little cheaper than that. thanks again.