Hey guys, so I've been working on my bike for a few weeks now, and when it works its great Now I would like to move on, and make the next big step. I would like to purchase the jack shaft kit from SBP. What are the things I should know before buying it? It says on the site to have a good derailur (spelling), and I'm not sure if mine is good. Also, will I have to replace the rear cassette gearing, or is the one I have default OK? I can take pictures, its a bike from about 10 years ago, its a MOTIV. I think that company is non existent now. I also have a 66/80 CC china HT engine.