If you own one of those pedal and chain mopeds don't waste your time with a bore kit, but if you own a honda elite-s, yamaha jog or a newer derbi and install a quality bore kit made by polini or malossi its no hype, if you want to see an engine almost identical to mine go to www.hiperformance-moped-parts.20m.com/ and click on project 1 moped pics. Remember with skill speed is unavoidable.....