I have an '07 Venture, 25k miles, stock engine/exhaust setup, carbs settings have never been modified (except being balanced a couple of years ago). A few days ago I changed the spark plugs and replaced the air filters for the first time. Instead of installing paper filters, I installed K&N filters. After putting the bike back together and taking it for a test ride, I noticed a (somewhat negative) performance difference. When accelerating through gears 1-4, or if I cruise around 40 MPH in 4th gear, there is an occasional sag. Overall, the bike still accelerates well, but the sag is more prevalent when holding a steady speed. Highway performance is good; cruising at highway speeds is smooth, and passing is no problem. Also, when decelerating, there is more popping, and an occasional backfire (when decelerating from highway speeds). The bike has never backfired before. Mileage is still around 40 MPG (I rode over 600 miles since the plugs/filters were changed). I thought the K&N filters were a direct replacement and no carb mods would need to have been made. Has anyone experienced this before? I still have the paper filters, and when I make time, I will put those back in and see if the performance goes back to the way it was.
Any other suggestions on what I could check?
Thanks!