Has anyone removed the Akro dB killer?

[Muckabucka]

Looks like this is bolted in place with a breakaway nut. Has anyone successfully removed theirs?
I think the bolt is stainless, so drilling out will be a PITA.
Mark

 

[cjwell]

Yes I have removed... It has a regular 4mm Allen head bolt in it BUT it does have a "tamper proof" piece rammed in there. Center punch it carefully and use a 4mm drill. Most will fall out then might have to pick a couple pieces out, then take your 4mm Allen and remove bolt. Took me a while to complete safely.

 

[Muckabucka]

Thanks cjwell.

 

[ryandalling]

How's the power with it out? Was concerned. My ninja 250 was actually 2 hp more with the thing in, as it created better back pressure. Also, concerned with noise at some of tracks.

 

[Dannycgfy]

take off the rubber plug you can see the bolt. Can't get at it easy though because they don't want you to remove it so it has that break off bolt. I just drilled mine out like Cj said, my drill and bits suck so it took awhile but it sounds a lot better without it. Definitely worth it

 

[Treachery]

Is the retaining bolt a hex, or tamper-resistant Torx?

Did you take the canister off the "header" in order to drill out/off the nub?

EDIT:

Okay, I will confess to being not keen to try to drill that tamper-resistant screw out. I chased down a set of security bits, and in among those are both 4 and 5mm bits. The question is whether I can get to the back side of the canister with it on the bike. I'll post up what I got so others can look for the tool.

Fill me in though: The "nut" that's sweated into the dB killer is secure enough to remove the screw, yes?

 

[cjwell]

Is the retaining bolt a hex, or tamper-resistant Torx?

Did you take the canister off the "header" in order to drill out/off the nub?

EDIT:

Okay, I will confess to being not keen to try to drill that tamper-resistant screw out. I chased down a set of security bits, and in among those are both 4 and 5mm bits. The question is whether I can get to the back side of the canister with it on the bike. I'll post up what I got so others can look for the tool.

Fill me in though: The "nut" that's sweated into the dB killer is secure enough to remove the screw, yes?

Its a regular old 4mm allen, (not a tamper proof torx). It is like someone used the wrong tool IE a ball end allen wrench and broke it off in there, everyone has seen that LOL. You'll have remove the muffler and CAREFULLY fixture it, I used the vise with soft jaws on the hanger part to hold it. The nut is TIG welded to the dB killer, the bolt is not overly tightened, after you gain access to the head, it will come right loose/out. It is tamper proof for the cup bikes, head bolts are safety wired with a ''tag" on it for cup too. Just trying to keep people out/fair.

 

[Treachery]

Thanks, cjwell. I finally looked at the head of the screw and discovered what you describe (back to the store to return the security bits)
I've got the KTM replacement hanger coming, so when I do that swap, I'll attack that little bugger.

 

[SHOW SCARECROW]

Please refer to

 

[Treachery]

Okay, ' crow; ups for the pics. But...you disassembled the muffler...how come?

 

[cjwell]

View attachment 308View attachment 309View attachment 310View attachment 311View attachment 312Please refer to

That was uncalled for....

 

[jokerio]

Yes I have removed... It has a regular 4mm Allen head bolt in it BUT it does have a "tamper proof" piece rammed in there. Center punch it carefully and use a 4mm drill. Most will fall out then might have to pick a couple pieces out, then take your 4mm Allen and remove bolt. Took me a while to complete safely.

take off the rubber plug you can see the bolt. Can't get at it easy though because they don't want you to remove it so it has that break off bolt. I just drilled mine out like Cj said, my drill and bits suck so it took awhile but it sounds a lot better without it. Definitely worth it

Thanks, cjwell. I finally looked at the head of the screw and discovered what you describe (back to the store to return the security bits)
I've got the KTM replacement hanger coming, so when I do that swap, I'll attack that little bugger.

So the $60thousand dollar question…..How does it run now, we know its louder but any power gains ?? Dyno anyone ??

 

[Rodolfo]

Yes

Anyone know if you gain or loose power with the db killer on or off?

 

[Wa2fst]

You do not lose power or gain with the db killer. Sole purpose is sound. once the air passes thru All the bends channels of the cat then thru the exhaust can is where your power is made once at the tip to the db theres nothing left but sound.

 

[jokerio]

You do not lose power or gain with the db killer. Sole purpose is sound. once the air passes thru All the bends channels of the cat then thru the exhaust can is where your power is made once at the tip to the db theres nothing left but sound.

I did some dyno work on a 250 ninja and actually gained 2 hp with a DB killer !! So, i don't think it's (always) that easy Wa2fst….

 

[ryandalling]

Some of the smaller bikes like the bake pressure created with the db killer left in. That's why I wanted to see if anybody did a before after Dyno. My 250 was more hp with it in also.

 

[cjwell]

My first bike the one I'm "building" when I collected Dyno data with I had it removed as you know. The cup bike I used for Pcv testibg I left in, tuned, removed, tested etc... My findings on the stock engine even with tuning it liked the dB killer. I'll retest with my engine kit and see if it still holds true. So in short on the stock set up engine with a pipe, k&n filter, lid mod and tuning leave it in. Curious as to see effect with new engine what happens. Hope to find out early next week

 

[Rodolfo]

Thanks cjwell

Another question will be, if The first silencer or catalitic converter on The akra pipe, and most of The pipes i have seen, helo or hurt The performance

 

[mr-fabricator]

I have the arrow system with a similar chamber / collector . Its completly empty so im asuming any pressure / sound wave aiding back pressure will end at this point as at entry point the exhaust gasses will enter a large volume area and pressure will be lost . Might aswell just exit straight to atmosphere ?

 

[cjwell]

The change is size/volume there 'ends' the primary header length. The primary length is what has tuning effect. Anything after the primary is called secondary and very little bearing on tuning/performance.