I recently purchased a YBR125 custom. It came with a GIVI A604 screen. I haven't been able to fully open up the taps yet as it's still in its break in period but it struggles to do much over 50 mph. Am I expecting too much from a 125 or could the screen actually be harming the aerodynamics of the bike? It doesn't seem to be keeping the wind off me at all.
I know that the custom isn't the most aerodyamic bike but I don't have the lumbar spine or shoulders for anything with a less upright seating position.