Occasiionally, especiallly after a high speed run, the bike will emit a very loud high pitched sound. It continues up to 20-30 seconds after I turn off the ignition. It appears to come from right under the tank, and I´mm wondering if it´s related to the tubing for the emission control system. Another thought: may be related to putting on my winter windshield, whose lower extensions (providing protection for the knees) may interfere with the air flow to the air filter intakes projecxting forward under the leading edge of the gas tank. Any thoughts, similar experiences?