So my bike needs a new chain, but they are pretty pricey. I've been looking around and I saw this little wind up toy car. Needless to say, I ripped that shit apart and saw that a rubber band was running the little guy. Now my question is, how big of a rubberband do I need to run my bike? It's a 2003 SV650s. Also, will I get major gains if I run a smaller rubber?