Yeah, my Ninja 400 is modded a bit now, but here is a funny story. This literally happened two days ago (4/13/2021).
We all know the Yamaha R6 is a very quick motorcycle, even among supersports, so this is a little indicator of the Ninja 400 being "fast enough".
I was riding in Beecher Illinois on Route 1 and about to get on 394, heading towards Crete (I ride through here a lot for not much traffic, faster roads, and decent scenery).
So a guy riding a blue Yamaha R6 passes me like nothing (think he saw me ahead of him and decided to whiz by). We end up at the light and were about to go on the expressway, I nod at him and he does the same. The light turns green, and I let him go first, then as soon as I turn the corner I gun it (my first performance test of my new mods). I pass him like he is standing still and then I hear his engine gun as well and see him coming up to me but slowly. We get off the expressway and start heading into Crete, there is a straightaway there after the turn.
After turning, I gunned it again and got up to 90 pretty quickly, he follows suit and it takes him a bit to catch up to me and eventually, by the time we are in town, he catches up to me and is right behind me. I turned into the first gas station to go to put gas in my Ninja 400 and I saw him follow me.
I get off my bike and pop up my modular helmet, and he comes up next to me and he asks me, "What IS that? That thing is quick!" I told him, "It is a 2021 Ninja 400 ABS" and point at the emblem, he seemed really surprised. I told him I do have a full exhaust and Power Commander V on it, along with other support mods (O2 Eliminator, Smog block off plate) and a generic Akrapovic tune on it.
He actually said he thought I was on a newer Ninja 636, which I am sure would have given his R6 a run for his money. I praised his motorcycle and asked him what he had done to it, just an Akrapovic slip on and fender eliminator. He said it was a 2020 blue Yamaha R6 and man, what a beautiful bike! We chatted a bit then he had to go, so I told him I would see him around and take care.
If a R6 owner is calling this a "quick motorcycle", it is no dog, that is for sure! While his R6 would eat the Ninja 400 alive in a race, even I was surprised how quickly I passed him and it did take him a bit to catch up to me. It has respectable speed and power and my mods have made it even faster.