2009 EG with stage 1. Under hard acceleration I hear a tink sound as soon as the throttle is opened up. It is a singular tink, not a rattle. Sounds like it's coming from front cylinder. I don't think it is an engine ping but maybe. It happens hot or cold. I can even get it to make that sound by blipping the throttle at idle. I've checked for loose components, all are tight. I'm using non-ethynol premium 91 octane in the bike. Possibly timing needs to be retarded. Any ideas?