Hi all just a quick question, my totally standard mc21 was up and down when ticking over between 1300rpm and 1800 rpm so decided to remove carbs to give them a clean ( found a bit of gunk in there) cleaned and blow out with compressed air, so looked at airfilter and somone has made one from a foam sheet badly there is about half inch gap all round so my question is the grill that's under the filter seems slightly big to fit in the ridge that's all round the box but too small to fit over ridge so which is it ment to be? In the ridge or over the ridge? I've now bought a new gem Honda filter but don't know which way to put the grill anyone had same prob?