Suzuki LTZ 400 - Z-Power in About an Hour - Off Road Alternatives

In less than an hour, we removed the stock foam air filter, stock lid, and exhaust, and we replaced them with the appropriate K&N and Muzzy components. With no tuning whatsoever, the air/fuel ratios were lean to say the least. With an air/fuel ratio of 17:1, some serious jetting was called for. With the help of K&N PowerSports engineer Charlie Tissen, we jumped as high as 165 main jets, shimmed the needle 0.025 inches richer, and moved the idle/air-mixture screw from a 3/4 turn opening (stock setting) to 2-1/2 turns. While this was ideal for our Z, factors such as altitude, fuel type, and weather can drastically affect jetting, so keep an eye on that plug. Alas, the power arrived with 96 decibels of thunderous roar, just at the legal limit for most recreational areas in the lower 48 states.

Just The Facts
We enjoyed riding the stock Z, but it lacked the throaty aftermarket exhaust tone we've become accustomed to. It was starving for air and fuel - two things we quickly fixed with the K&N filtration and new jetting. The bottom line: We love the sound, and the performance increase was quick and easy.