I purchased Norton Motorsports’s package deal a few weeks ago for my ninja 400. It includes an exhaust system, a set of custom made velocity stacks, and a flashed Ecu. I went with the Graves full exhaust, Norton by far has the best price I have found for this system. I sent my ECU to be flashed by Jesse at Norton, i opted to keep my original ecu, but you can speed the process up by paying a little extra for a core charge and he will send a flashed ecu to you and when you send your original ecu in you get your core charge refunded. That way your bike never has to be put down.
I installed the exhaust, which fit like a glove and sounds great, and pulled the airbox and installed the Norton velocity stacks. These stacks are custom made backed with dyno tuning during the design process, not some generic stacks pressed into the oem stacks. I removed the snorkels and put everything back together. Norton recommends cutting the airbox to allow more airflow, but I have not cut mine yet. I will probably pull the tank in a couple weeks once winter sets in and cut the box. The difference in performance is purely amazing, the throttle response is very crisp, the bike pulls through the gears harder. Throttle is smoother, I can’t believe the difference this made. It really does not feel like the same bike, it feels like a proper sport bike now.

Without a doubt this was money well spent. I would definitely recommend the ecu flash and velocity stacks to anyone with a ninja 400 or Z400. It really wakes this bike up.


Jesse was fast responding to questions I had throughout the process, I was talking with him through emails before I purchased the parts and then later as I had more questions. Being a career mechanic for two leading brands of commercial vehicles I am always questioning and looking beyond the stated facts. Jesse was more than helpful and is knowledgeable about what he is talking about. I could tell he is passionate about motorcycles, and obviously has a talent for finding horsepower in the small displacement sport bikes.

Took the bike out this morning for a good ride. It’s the first chance I’ve had to put some seat time on the bike since the mods.
Throttle roll wheelies!! I didn’t think the 400 would ever do that on stock gearing.

Can’t wait to order the stacks

they make a dramatic difference in power. especially when coupled with the ecu flash

Did you lose much low-end torque? The 400 has significantly more torque than 250/300 and totally leaves them in dust across intersection.

From the seat of my pants I cannot feel a loss in low to mid rpm range. According to the dyno sheet that posted on the website for this combination of parts upgrades, it does lose a bit down low. But it makes way more mid to high than it loses down low. I’d say it’s a very good trade

I was very interested in the Norton Velocity stacks. They do recommend cutting the air box for more air flow. For racing you can’t alter the stock air box. For 299 you definitely want to do everything they recommend to get your moneys worth.

when i tear the bike down for cams, i'll be cutting the airbox. i was going to get a spare box before i cut, but if i wait longer to buy, the junk yards will have more wrecked 400's so the box should come down in price later.