My bike will not accelerate past half throttle

Well I have a yamaha majesty 400cc injected scooter.

The problem I am having is when I accelerate to full throttle it lags but when I throttle down to half it picks up a little.

I think it may be a bad line or the fuel pump. Just looking for a little help. And the day when this started I had the bike up around 80mph when I lost power,got home and the air filters are blown off . I put the filters back on and that was the start of my problems. I would appreciate any help Thank you.