just have to work and press down from all sides. also on the front on top i cut about 1/8 inch straight across the top part of the foam not the plastic on the filter. took the stock filter out and compared the foam on the bottom trim just hair loo at both side by side you will see what i mean. put if you don't want to go to the trouble rocky mountain is calling k/n tommrow because that had 5 calls in the last to days. my problem was the bike was jetted last night and i have a hmf pipe stearing me in the face. one of the nices pipes i ever seen.should have it insatalled in about hour or so. leaving the filter in for couple hours so it will form to the box better.should be easy next time to install.