Try front forks mounted wind deflectors. I had a bigger bike once but couldn't figure out why the wind was hitting my helmet so hard even with a big windshield. I then played with lower fork mounted wind deflectors and they corrected the air flow problem. Moving around your existing windshield may or may not fix the issue.Using an HJC helmet, couldn;t beat the price, but getting lots of head buffeting. I already put a post about the windshield and have moved it all around to no avail. Before getting a larger windshield, I am thinking about getting another helmet to try out. Any advice on a helmet that is "aerodynamically" friendly but won't break my budget?
I fought that problem for a LOT of years until a seasoned rider told me that the offending air probably was coming from UNDER the shield instead of over it.Try front forks mounted wind deflectors.