The reliability of the Yamaha R6 is a mixed bag, depending on various factors and user experiences. Some owners have reported high reliability, with one user mentioning 120,000 km on their 2007 R6 without major issues, highlighting the bike's robust engine and handling. However, other owners have encountered several mechanical problems. For instance, a 2006 R6 owner experienced issues such as a corroded ground strap, leaks in the cooling system, a faulty starter relay, and problems with the charging system, despite regular maintenance. Common issues include gearbox problems, particularly between first and second gear, and electrical issues like throttle position sensor and coil problems. The bike's design, which prioritizes performance over everyday reliability, can also contribute to these issues. In summary, while the Yamaha R6 can be reliable for some owners, it is not immune to mechanical and electrical issues, especially if not properly maintained or if it has been used extensively.