My 2002 M2 has a Forcewinder air intake, Mikuni carb, racing chip and Vance & Hines muffler. My engine has what sounds like a slight knocking or ticking sound. Sometimes I think I´m losing my mind because sometimes I hear it and sometimes I don´t. Does anyone else with a 2002 M2 have this issue? If you have this or know what´s causing this please let me know...