Hey all. I currently have a 4-1-2 Akrapovich on my 2018 zx 14r Performance that came from the factory.Do you reckon I would see a noticeable boost in performance and weight reduction from changing to a Yoshimura 4-1 exhaust?

Seat of the pants, IDK. Dyno will show who pops in whatever change in range.

I really only noticed the first big weight reduction going from stock exhaust to a full system. It's not a real light full system but way lighter than stock. So I'm saying, if you already are used to a full system, I don't think just losing one muffler is going to feel a lot different. I never had a dual aftermarket exhaust though.

You'd have to look at the dyno sheets to compare performance but I'm guessing you're getting a little better torque with the duals and that's something much more usable than peak hp. Just compare the dyno sheets. You should be able to dig up some weight numbers too. If it's a matter of three pounds, no, I don't think you will feel that. I don't think a difference of ten pounds would be something you notice a clear difference in.

Yoshi's a fine pipe but Akra is among the best if you ask most people.

I'd go with the one that makes the best peak hp but I'm kind of obsessed about that. In real life, we're not going to feel a difference since we might be talking 4 or 5 peak hp at most.

If you're happy with what you have, I don't think you'll be happier with a single if you're looking for better power and less weight. They're going to be virtually the same. If you take the whole exhaust off, you still have over 500 lbs of the rest of the bike and you already have 190 - 200 hp.

....but there have been people who tried many full systems and have a clear favorite for performance. If definitely having the very best is what you need to have (and I totally get it if you do), go with what they use in racing. No need to spend the money to compare, just go with what the fastest bikes use because they already did all the research. I think you already have pretty close to what you're looking for. I'd expect to see lots of Akras and Brock's, usually singles and there'd be nothing wrong with a Yoshi, just not the pick of the most serious race people.

Thanks Rook for your detailed and really helpful answer

Sure. Another thing you might be able do is to take LH muffler off and block the pipe using some kind of a cap (maybe it was fabbed out of a piece of sheet metal) and a hose clamp. Someone had done that on here and the bike ran fine. If nothing else, this will give you an idea of what the weight difference feels like and how the bike looks with a single. It also allows very easy access to the drive chain for maintenance.

* Last updated by: Rook on 1/23/2025 @ 3:07 PM *