Adapter Kit: OEM Suzuki GSXR Shock to Kawasaki Ninja 400 / Z400 (OEM Suzuki GSXR Shock NOT included)
A great, budget friendly shock upgrade for your Kawasaki Ninja 400 / Z400 is to use the OEM shock from a GSXR600 or 750/1000 (depending on your weight). However the GSXR shocks are much too short, about 315mm, for proper ride height on a Ninja 400 (The OEM Ninja 400 shock is 320mm for reference). You can solve this by reversing the upper shock mount on the Ninja 400, which provides the necessary additional 14mm of ride height to get the overall length right in the middle of the ideal range for aggressive riding and track use. However, when you do this, you can no longer use the OEM battery box mounts, so this kit includes new battery box mounts and spacer washers for the lower mount to fit the GSXR shock. Now you can get the correct ride height and keep your battery box mounted solid. A perfect, budget friendly shock solution for your Ninja 400 or Z400!
The shock is very capable on the Ninja 400, and I personally raced one of my races the final round of the 2019-2020 CVMA championship on a GSXR shock with this kit to test it out and won my race to wrap up the Expert Ultra Lightweight Shootout championship!
I definitely recommend having a competent suspension tuner setup your shock the first time, especially since used shocks may have oil that is no longer ideal, so adjustments may vary between shocks. But here is some baseline info you can start from:
The GSXR shock has high and low speed compression adjustments, rebound adjustment, and a collar style preload adjuster with 192mm length spring. I recommend starting with 10mm of spring preload, which means the compressed spring should measure about 182mm. Set the rebound adjuster 1/2 turn out from fully closed. Set the Low Speed compression adjuster (the outer adjuster) to 2 3/4 turns out from fully closed, and the High Speed compression adjuster (small center flathead screw) in the middle of the range, which is 2 3/4 turns out from fully closed.
Make sure the GSXR shock you purchase looks like this to ensure fitment: