TST Industries Takes On The Kawasaki Ninja 400 Airbox

With a growing collection of Kawasaki Ninja 400’s in the TST race paddock, our WORX engineering team has been hard at work to find performance advancements that will land TST riders on the podium, and their latest innovation is what brought you to this article – our all-new WORX Airbox system.

Not only does our airbox look like a top-tier race component stripped right out of MotoGP, but it also packs a performance punch. This isn’t some type of attachment you have to connect to your airbox or some modification that requires you to cut up your stock components – no, this is a complete overhaul. Our WORX Airbox completely replaces the stock setup, saving you 2.5 lbs in the process. By keeping the stock airbox intact, it also means that if you ever sell your bike or need to go back to a stock setup, you have the ability to do so. We aren’t big on destroying or permanently modifying stock parts here at TST. In fact, we made sure there’s no modification required to any part of your non-ABS Ninja 400 except for a small frame tab that is used to mount ABS components, but isn’t functional on the compatible non-ABS models. Many racers remove the tab entirely to aid in weight reduction, but we’ll leave it up to you to decide if you simply want to bend the tab, or remove it altogether.

TST WORX Airbox for the Kawasaki Ninja 400 TST WORX Airbox for the Kawasaki Ninja 400


The all-new airbox drops in and is ready to provide increased and precise airflow to your Kawasaki’s 399cc engine. The improved airflow can be optimized with our TST WORX Tune, or your own, to improve engine performance where it’s needed most – the higher range. When racing, you spend a good amount of time in the top rev range of your engine trying to separate yourself from the pack, so that’s exactly where we wanted to add more power. When tuned appropriately, our WORX Airbox can provide an 8% increase in peak power compared to the stock airbox, and 5-10% increase in the upper range between 9500 and 12500 RPM.


Those impressive power figures are a result of the purposefully engineered airbox paired with what comes inside of it – our all-new V2 Velocity Stacks. The V2 set improves upon our original design by focusing the volumetric efficiency to result in upper-end power gains. When the Airbox and our Velocity Stacks combine, it results in podium-worthy performance gains. The newly designed velocity stacks aren’t the only impressive thing hiding on the inside of the gorgeous airbox, however. In order to keep the Ninja 400 engine healthy and reliably protected, we developed a proprietary reusable open-cell air filter that perfectly fits within the airbox to keep dirt and debris out of your engine. Once it’s dirty, simply wash it with your favorite air filter cleaner and then reapply your preferred air filter oil, reinstall, and you’re good to hit the starting line.

TST WORX V2 Velocity Stacks included in the WORX Airbox Power figures demonstrate significant gains in the upper RPM range


Having it perform well isn’t everything though. We all respect a beautifully crafted exhaust, so we wanted to create something equally alluring for the front of the engine’s performance sequence. That’s why we went out of our way to design an airbox that stands out from the rest of what is on the market, not just in the performance gains, but in the way it looks on your Ninja 400. The large gloss carbon fiber intake leads to a matte black high-strength polymer, contrasting each other and drawing attention to the clearly overhauled shape. We didn’t skip the little things, either. The red accenting and unique mounting brackets add an extra layer of style that make the entire airbox assembly look like a MotoGP prototype designed specifically for your Kawasaki Ninja 400.

Kawasaki Ninja 400 with the TST WORX Airbox installed TST Industries WORX Airbox installed on the WORX Race Bike


We all love working on our bikes, but we love riding them more. That’s why our airbox assembly comes fully pre-assembled and ready for installation. If you’ve sent your ECU to us to be flashed with our Stage 3 tune, getting back in the saddle and feeling the performance gains at the top end is a relatively simple installation that should have you back on the track in no time.


Our WORX engineers continue to make strides in performance on the Kawasaki Ninja 400 platform, and the all-new WORX Airbox is the latest and greatest achievement. It’s been used extensively within our own race team and has helped lead to faster lap times that we simply couldn’t have accomplished without it. Now you can experience the same gains that our TST riders have been enjoying and gain an edge in the fight for the podium. Are you ready?

Want to learn more? Click HERE to head over to our product page and see detailed data on everything mentioned above.

About Robert Callahan
I ride a 2013 Honda CBR600RR and 2022 Honda Grom...oh and I do some marketing stuff, too.

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