I did this after finding nest:My 2015 CTX DCT ABS had only 1100 miles on the odometer when I bought it two years ago. I was only getting me around 37 mpg average and I wasn't riding it hard at all. I drove it like that for two years because I had no idea what the mileage was supposed to be and the bike seemed to run fine. Once I saw people posting 60+mpg in this forum, I decided I needed to investigate why my mileage was so poor. I had never checked my air filter because I read it was good for 10,000 miles and it's a PITA to get to, but decided to check it anyway after seeing the gas mileage others were getting. Once pulled, I discovered an actual mouse nest had been in the filter housing restricting much of my air flow. I cleaned out the nest and replaced the air filter with a new one. My next tank of gas got me 59 mpg, so I've improved, but still not where I feel it should be. Next I'll replace the plugs and see if I can't break into the 60+mpg zone. It scares me to think that had I not joined this forum, I would have ridden another 6,000 miles before finding that mouse nest.