Today I started to swap the fuel tank over while I was at it I changed the air filter and I noticed the small little filter called FILTER, SUB AIR CL VFR400R3 is not present would this cause problems as it's not there and I want to fit it all back together tomorow any ideas can I cut a filter to fit or leave out as it is now or just wait untill I order a new one

You could cut out some foam and put it there, personally i have no filter there.

Thanks for reply