Hi, my 2018 GSX-S 750 has had a noise coming from the engine for about the last 1,000 miles. Bike has 2,100 miles now. Trusted mechanic says it is harmonics that are normal. Just curious if anyone else with a 2018 or newer has the same noise? Only happens at 5,000 rpm in 2nd, 3rd, 4th, and sometimes 5th gears. Sounds like a quiet grinding noise & just lasts a few seconds.