Removing the akrapovic DB-killer

[KennyNorge]

so how much difference does this make.
I find the Akra to be ok, perhaps a little on the quiet side, but pretty good for those longer trips.

Any videos that show the difference between modded and non modded DB killer?

I guess I could make a compare with KennyNorge, after all he lives about 5 minutes away from me

Yes, we can compare one day, preferably a sunny day

I am going to expand the four holes today after work from 6,5mm to 8mm. I guess that should do it Just giving it a touch more deep rumble. Doesn't get much louder, only deeper... more base

 

[Noggie]

Yes, we can compare one day, preferably a sunny day

I am going to expand the four holes today after work from 6,5mm to 8mm. I guess that should do it Just giving it a touch more deep rumble. Doesn't get much louder, only deeper... more base

Ok, I'm going to work next week, so we might have to wait to late July or August to make a compare.

 

[KennyNorge]

Four 8mm holes (probably) gave the sound I was looking for ? still in the process after feedback of other solutions ;-)
View attachment 2072

 

[StoneBridge]

Hi KennyNorge, nice work! It isn't too difficult to replace back the dBk?

I've cutted the inner pipes halfway, as others recommend it. Replacement is just 2 mins, and the sound is perfect for me if I use it in longer runs.
The truth is I love the sound without the dbk, so I use it without at urban riding.

My dBk in/out comparison vid:
[video=youtube;YYgUX_alE4Y]https://www.youtube.com/watch?v=YYgUX_alE4Y[/video]

 

[KennyNorge]

Hi KennyNorge, nice work! It isn't too difficult to replace back the dBk?

I've cutted the inner pipes halfway, as others recommend it. Replacement is just 2 mins, and the sound is perfect for me if I use it in longer runs.
The truth is I love the sound without the dbk, so I use it without at urban riding.

My dBk in/out comparison vid:
[video=youtube;YYgUX_alE4Y]https://www.youtube.com/watch?v=YYgUX_alE4Y[/video]

Hello. I grinded the inside of the wider parts of the inner pipes, made it a bit easyer to change but not easy enough. Still have to pull pretty hard, use wd-40 and "hand-tool" (don't know the english word). But I don't have to remove the whole exaust from the bike and hammer it out from the innside.

I am really tempted to cut the inner pipes like you to make the change easy. I allsoe have come to really enjoy the sound without the db-killer in after swapping back and forwad in the process. But public regulations/laws forbidd the amount of sound the Akrapovic puts out without the db-killer. But if I do like you I can take it out some times when it is "safe"

Thank you for sharing the video, I will give it a good listen when I get home with proper hifi. So maby after a couple of days riding with it like it is now I might go for your solution

 

[Zoran]

In one attempt not been able to take off db killer.
Anyway I have been thinking in one direction, is it possible to do following:

View attachment 2187


so I can customize the sound on the fly moving the pipes (new installed pipes) with screw?

Any comment?

 

[strelk112]

Is it social?

Hi KennyNorge, nice work! It isn't too difficult to replace back the dBk?

I've cutted the inner pipes halfway, as others recommend it. Replacement is just 2 mins, and the sound is perfect for me if I use it in longer runs.
The truth is I love the sound without the dbk, so I use it without at urban riding.

My dBk in/out comparison vid:
[video=youtube;YYgUX_alE4Y]https://www.youtube.com/watch?v=YYgUX_alE4Y[/video]

How long are your inner pipes now mate? I absolutely love the sound without the db killer but seeing as I go to work super early on my bike its not really an option to use it without. How social would you say the bike is with the mod as a video you can't really get the true experience

 

[StoneBridge]

How long are your inner pipes now mate? I absolutely love the sound without the db killer but seeing as I go to work super early on my bike its not really an option to use it without. How social would you say the bike is with the mod as a video you can't really get the true experience

I know what you mean... Bottom pic says it all...

I think the inner pipes now are about 4-5 cm long. I've cutted near to the middle point.

With the mod it will be absolutely social, because the deep growling becomes a low thumping...
At high revs the sound will be acceptable, only the cracklings will not be as brutal as w/o the dBk.
I hope I could help.


View attachment 2225

 

[twil]

Did someone tryed to just remove one of the pipes, letting the otherone alone?

 

[KennyNorge]

Hi KennyNorge, nice work! It isn't too difficult to replace back the dBk?

I've cutted the inner pipes halfway, as others recommend it. Replacement is just 2 mins, and the sound is perfect for me if I use it in longer runs.
The truth is I love the sound without the dbk, so I use it without at urban riding.

My dBk in/out comparison vid:
[video=youtube;YYgUX_alE4Y]https://www.youtube.com/watch?v=YYgUX_alE4Y[/video]

Hello! Well! It's done [emoji4] I cuttet the inner pipes in half! The sound is amazing [emoji1] Deep rumble and agressive when revving, but still within my neighbours comfort sone 06:00 when I leave for work [emoji1] I have ridden 8800km but now It was actually like getting a new bike.

 

[addy]

Was riding for a while with modified db killer (inner pipes cut by half) but after having it out the past month its just too quiet and not deep enough with it in so I went kinda over the top modifying it.

Removed 95% of the inner pipes, cut back the outer pipes (mostly for looks) and drilled two 12mm holes in the cylinder part and now it sounds perfect lol...... well as closed to it as I can get with the db killer in.

 

[craigieboy]

Quick video of mine with the modified DB killer 4 sets of 3 8mm holes.

[video=youtube;GfUXsLuqxqs]https://www.youtube.com/watch?v=GfUXsLuqxqs[/video]

 

[donut]

When my db killer was first removed it was easier to do by removing the exhaust and pushing it out rather than pulling it out.

I have now cut most of the inner tubes away (in stages - with no discernable difference between removing the fat parts and now just leaving about 1cm) and have drilled a hole in both the pipe and db killer roughly opposite the original to make removal and replacement an easy 2 minute job and have re-secured using an allen bolt/nut with a spring washer to secure in place.

Seeing that a pic is worth a thousand words and all that here is what I've done:

Started with removing about 2 inches of internal pipe, then removed another half inch or so (no real difference between the 2 to be honest) to leave about 1 inch of internal pipe. As you can see from the pic I've mashed one of the external pipes a bit with grips to remove the db killer. The hole you can see is one I've drilled to re-secure the thing to make life easier.

View attachment 2236

Here's the db killer in place with a new hole on the outside of the exhaust:

View attachment 2237

And here it is with a bolt to secure it in place:

View attachment 2238

I now use a spring puller (easily and cheaply available from Ebay) to remove the db killer when I want to:

View attachment 2239

Like this, in case you're in any doubt:

View attachment 2240

As mentioned before though, unless you re-map to run without the db killer the engine will run very lean. Here's my dyno chart to show both the power / torque gain without the baffle (2 bhp / 1.4 Ft/lb) - and the air / fuel mix. With baffle about a perfect 13 to 1 but without a very lean 17 to 1 with a risk of damaging the engine.

View attachment 2241

I guess the MT-07 has more of a torque plateau than a torque curve.

 

[mixim]

@Donut
Do you know if your mod of the dbkiller pipes affected the fuel to air mixture in any way?

On a scale 1-10 where 1 is stock exhaust and 10 is without baffle.
How would you rate the loudness after your mod?

Also... Theoretically, does drilling holes in the inner pipes would have similar (non)effects to the micture as cutting them?

@ Rest of y´all
TheNiekoss on Youtube has uploaded a really really good and detailed video guide on how to remove the db-killer without damage, he also did the drill mod. Check it out!
[video=youtube;bThJ4V8Bg9A]https://www.youtube.com/watch?v=bThJ4V8Bg9A[/video]

 

[Scim77]

Hi Donut
Can you advise if you are still running in baffle-out mode. If so, how did you correct the air/fuel ratio. Did Steve Jordan do it for you? Did you resort to the Power Commander route or maybe consider Hilltop Motorcycles? It would be interesting to know. Apologies if you have already covered this on an earlier thread.

 

[Darren]

Seeing that a pic is worth a thousand words and all that here is what I've done:

Started with removing about 2 inches of internal pipe, then removed another half inch or so (no real difference between the 2 to be honest) to leave about 1 inch of internal pipe. As you can see from the pic I've mashed one of the external pipes a bit with grips to remove the db killer. The hole you can see is one I've drilled to re-secure the thing to make life easier.

View attachment 2236

Here's the db killer in place with a new hole on the outside of the exhaust:

View attachment 2237

And here it is with a bolt to secure it in place:

View attachment 2238

I now use a spring puller (easily and cheaply available from Ebay) to remove the db killer when I want to:

View attachment 2239

Like this, in case you're in any doubt:

View attachment 2240

As mentioned before though, unless you re-map to run without the db killer the engine will run very lean. Here's my dyno chart to show both the power / torque gain without the baffle (2 bhp / 1.4 Ft/lb) - and the air / fuel mix. With baffle about a perfect 13 to 1 but without a very lean 17 to 1 with a risk of damaging the engine.

View attachment 2241

I guess the MT-07 has more of a torque plateau than a torque curve.

Hi Donut, Was your Dyno run done with your modified baffle?...Cheers

 

[Triple Trouble]

View attachment 2241

I guess the MT-07 has more of a torque plateau than a torque curve.

Is that figure at the crank or wheel?
I'm surprised uv got 69bhp. We've managed 72-73 at the rear after a few goes at mapping it? Are you going to get it done anymore?

 

[Darren]

Finally made the step of removing my baffle and cutting the inner pipes by half. What a difference, glad I did it. I use wrench pliers with rubber strips I folded over the jaws to protect the exhaust from damage and with persaverence with a rubber mallet the baffle came out. I used some course sanding paper on the ring of the baffle to polish it up then cut the inner pipes. It was so easy to put back in and I was able to locate the original fixing hole using the head of the allen key first then insert the bolt and replace the rubber grommet. Good job done...........

 

[Darren]

Finally made the step of removing my baffle and cutting the inner pipes by half. What a difference, glad I did it. I use wrench pliers with rubber strips I folded over the jaws to protect the exhaust from damage and with persaverence with a rubber mallet the baffle came out. I used some course sanding paper on the ring of the baffle to polish it up then cut the inner pipes. It was so easy to put back in and I was able to locate the original fixing hole using the head of the allen key first then insert the bolt and replace the rubber grommet. Good job done...........

Please see attached picture of no damage to baffle.........excuse the slippers!

 

[bobh]

Is that a Womble?