Cheap chinese DB killer – exhaust muffler review

Proper review a cheap chinese product: this time, it’s a DB killer (or exhaust silencer) that you can easily find on Aliexpress or Banggood. It’s cheap, but is it any good?

I’m doing a few reviews of cheap stuff I buy on the internet. It’s sometime hard to find in-depth reviews of cheap stuff from Aliexpress or Banggood, or whatever other site. Let’s try to address this.

My Yamaha is equipped with a Two Brothers dual exhaust slip-on system (yes, the Yamaha FZ6 has 2 exhaust pipes). It’s nice, looks good and sounds amazing. I bought my bike like that, but I would have probably never put that kit on as it’s really expensive.

And it’s actually loud, not super loud, but loud enough to be annoying when cruising around town at 50km/h (30mph) in summer, even at low RPMs. I repacked them last year before the riding season but it almost didn’t change anything.

So in order to reduce the decibels a bit, I found cheap DB killers on AliExpress. There are different sizes available, and quite a lot of different vendors, but I think they all come from the same factory as they all look the same. They’re supposed to fit most exhausts.

Anyway, a bought a pair of those silencers. I actually firstly bought 140 x 35mm ones, but I later found a better idea to made them fit in my exhaust pipes with a bigger size. So I ordered another pair, 140 x 60mm, from the same vendor. And instead of receiving two of those, I got one 140 x 60mm and one 140 x 45mm. No idea why.

The DB killer is nothing crazy, it’s basically a small pierced pipe. On one end, there’s a removable cap; that side is supposed to go in the exhaust.You can remove the cap entirely, or move it to a different position.

The other end has a specific shape that is supposed to be placed at the end of the exhaust pipe. That shape has different size, to accommodate the different exhaust pipe sizes.

The screw at the end is there for maintaining the muffler in place in the exhaust.

The 2 screws are the same size. I don’t know if they would hold well though, I will put some threadlocker on to be sure they won’t fly away when riding.


There is really nothing complicated about this kind of db killer. You just have to measure the tip of your exhaust before you buy the proper one. If your bike only has 1 exhaust pipe, you can even order different sizes if you’re not sure, because it’s so cheap.

This is one exhaust pipe. The golden tip has a flange inside, which is not visible on the picture. That flange is handy as it’ll prevent the db killer to fall all the way in the exhaust, which will be a pain!

Now we just insert the db killer in the exhaust tip.

The last step is to use the screw to tighten the muffler to the exhaust so it doesn’t fly away when going full throttle. Don’t forget to add some threadlocker on there too.

As you can see, it doesn’t look super clean. The fact that it’s chrome looking makes it too visible. The light I used when taking the picture really accentuate that too. I might paint it black with high temperature paint. It’s especially visible on my bike as the exhausts are quite high, just below the passenger seat.

It’s time for testing the sound now. It’ll be interesting to see if removing the end cap changes anything, or even moving the end cap to a different position.

Update: tested on the bike

My goal here was to reduce the noise of the exhaust (reduce the decibels) which is just too loud.

I’ve ridden the bike with the db killer in place, and it didn’t change the sound much, unfortunately. I’ve even installed them differently, where I thought they would be more efficient, but no significant change. The sound itself changed a bit, but it did not reduce the noise, which was still too loud.

I did try to move the cap to different positions, but it produced a very minor sound change. I’ve even had some problems when putting the cap too close to the outlet, the exhaust gases couldn’t escape quickly enough and it changed how the bike responded, not in a good way.


So what do I make of this? I looked at other exhausts like Akrapovic or LeoVince. Those brands usually provide a db killer with the exhaust. And adding/removing it would change the noise quite a bit. But that’s probably because the exhaust are built with that purpose. I’m guessing the TwoBrothers exhausts aren’t built the same way. They don’t have a db killer, they don’t provide one as an option either. So I think this type of db killer is just not working for TwoBrothers exhausts.

I guess there’s no way to know in advance how it’ll affect the noise, until you try with the exhaust you have.

Regarding my bike, I actually went back to the OEM exhaust. It was the only cheap and easy option. I just couldn’t bear the noise of the TwoBros anymore. And I don’t want people to look at me riding and think that I’m a douchebag making too much noise. I know some riders don’t care, but I’m not one of those. Like some others, I thought that making more noise makes you safer on the road since you’re more noticeable. The truth is, it barely change anything. I don’t feel less safe at all. I do ride on the highway and in the city, and I honestly didn’t notice anything that would make me put back the loud exhaust. I like my bike more, and I can still make decent noise if I have to, by revving it to 10k rpm.

Sorry for the lame watermarks, but some vendors quite like to steal pictures to use as their own.

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6 thoughts on “Cheap chinese DB killer – exhaust muffler review”

    1. The way I have them setup in the article didn’t work out well as it doesn’t make a tight seal. I had to use some high temp gasket maker to close the gap, make it tight and it was better. I’m still working on this and will update the article once I’m happy with it.

  1. You can wrap a layer of 5mm repacking mat around the db killer pipe and it will make a difference.

    These db killer are very efficient so you are not installing them the proper way I guess.

    1. I think you’re right, wrapping packing material around was probably how it was meant to be used. Unfortunately, I can’t test that out anymore since I sold that bike.

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