Something is definitely wrong with your tuning. My streetmate does low 40s to 48ish on flat depending on head or tail wind. That's with a trunk packed full to the top, me at 210lbs and my bag is probably 15-20lbs. Jacket is heavy too. My bike is stock aside from some minor port work, 20lb first & 25lb second clutch springs, a biturdo and a 24 tooth rear sprocket. Maybe it's because I bought it in New Jersey lol, but that's radar sign (like the signs that tell you your current speed) and GPS confirmed.