Removing DB killers from '21 Euro5 akra high mount

4771 Views 18 Replies 8 Participants Last post by AntTwon, 2 mo ago

NocGSAR18

Discussion Starter · Jan 17, 2022

2

Has anyone modified their akra high mount Euro5 exhaust yet? As in remove the small db killers from the factory. I saw the thread for the low mount mount euro 4 with the same mod. But didn’t see if anyone did the high mount akra like I have on the urban GS.

Seems to be similar. I took the end cap and it seems like they just tack welded the inner db killer in a few places. Should just grind them down and pull them out.

Thoughts?

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Gambo916

· #2 · Jan 17, 2022

I've never done this myself on a nineT (but have on other bikes)............but I'd say a few minutes work with a Dremel or some other similar type of small grinder will have those pesky DB killers out no problem.

NocGSAR18

Discussion Starter · #3 · Jan 17, 2022

4

Well I had the day off today and got done shoveling the snow. So I went to tinker …it’s doable and done.

I took off the caps and rings and yanked the pipe off the bike.
Whats holding on the db killers are the 3 spot welds on the outer top. I punched them then drilled the spot welds out with a 11/32” bit.
At that point they were no longer attached but they are still pressed into the tips.

I did something similar with a SC can I got 2 years ago and had to remove the “non removable” db killer. I wrapped a length of 3/32 TIG wire into a vise and made a hook on the other end.
Put the hook into the pipe and yanked back on the pipe. It took a few tries but on the 5 pull it came flying out. View attachment 150360

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NocGSAR18

Discussion Starter · #4 · Jan 17, 2022

Upper can was the same but much more stubborn. The SS was eating drill bits alive. So I had to get a new bit and upsize it by one size. This also killed the bit and I think rewelded it again from heat.
I got out the dremel with some tungsten carbide deburring and grinding bits to clean out the holes.
Then let some wd40 sit on the tip facing up to to soak into the crack between the db killer and outer tip.
Came out 5 pulls later.

I’ll have to weld up the holes tomorrow so exhaust doesn’t blow into the caps.

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Noel61

· #5 · Jan 18, 2022

How are you going to weld the holes? I assume they are stainless.... not so much the holes.... I know they are air..... haha!

NocGSAR18

Discussion Starter · #6 · Jan 18, 2022

Well I tried and stopped after halfway into the 1st hole. The stainless is paper thin and my machine was too powerful, even on the lowest voltage and amperage. With stainless wire, I tried MIG and TIG and was instantly making the hole slightly larger by the time the arc started. Most of the welding I do is steel and this delicate SS stuff isn’t exactly in my wheelhouse. i was able to backfill it slightly. Unless I can get my hands on a much better TIG machine, the holes will stay. If anything I’ll get some stainless hardware and fill the holes with small Allen key bolts and nuts to give it a finished look.

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Bobber101

· #7 · Jan 18, 2022

Maybe get some thin stainless sheet and cut it into strips, fit that into the inside and tig weld the holes?

Tigcraft

· #8 · Jan 18, 2022

If you struggle welding holes up then you need a ‘helper’ sheet of copper clamped to bridge the hole on the other side. It works as a mould so you can fill weld up to it then just pull it away.

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Noel61

· #9 · Jan 19, 2022 (Edited)

I know welding it up was going to be beyond me.... mig on 1.2mm steel is my limit!... what about a stainless cable clamp around the holes...... the thin stainless zip type ones.... then the end cap back on..... this is what I was thinking.... but haven't got to it yet..... I'm making a front rack at the moment.... with 1.2mm tube.... haha.

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Noel61

· #10 · Jan 19, 2022

oh.... how does it sound?

Tigcraft

· #11 · Jan 19, 2022

Noel61 said:
I know welding it up was going to be beyond me.... mig on 1.2mm steel is my limit!... what about a stainless cable clamp around the holes...... the thin stainless zip type ones.... then the end cap back on..... this is what I was thinking.... but haven't got to it yet..... I'm making a front rack at the moment.... with 1.2mm tube.... haha.

View attachment 150423

Oh no but it’s better than a nylon cable tie! What you can do also if you’ve a tig with HF start is melt the stainless wire on its own to form a ball or a rain drop however you want to see it then do as I’ve said above with the copper and rest it in the hole then apply heat till it just melts in. If you don’t have a go you’ll never know.

Chopper_Bob

· #12 · Jan 19, 2022

Slice a ring of just below the openings?

Anthonie

· #13 · Jan 21, 2022

NocGSAR18 said:
Upper can was the same but much more stubborn. The SS was eating drill bits alive. So I had to get a new bit and upsize it by one size. This also killed the bit and I think rewelded it again from heat.
I got out the dremel with some tungsten carbide deburring and grinding bits to clean out the holes.
Then let some wd40 sit on the tip facing up to to soak into the crack between the db killer and outer tip.
Came out 5 pulls later.

I’ll have to weld up the holes tomorrow so exhaust doesn’t blow into the caps. View attachment 150363

Why do you want to weld the drill holes up? Unless for aesthetics, and/or you went way larger than a 6mm drill bit, it would be totally unnecessary. Put the end caps back and enjoy those open Akras, - Basta!

(Mine is left open, neat little holes. On the other hand, my buddy went nuts and drilled 10mm holes after wrecking x amount of drill bits. His urban now has a whistle that would scare the living daylight from Santa's Reindeer)

PS. drill paste is very important as is cobalt drill bits.

NocGSAR18

Discussion Starter · #14 · Jan 22, 2022

Sorry for the late reply. Crazy work week. One of those wake up extra early, work 12 hours, go home pass out and do it again the next day weeks. Lol

yeah welding it was out of the question I had a copper backing spoon for large steel welds but it want going to work in this case. Tried a stainless band clamp but either the worm drive or tensioner wouldn’t allow the end cap to sit on the can all the way.

what I ended doing is is getting some small M6 stainless hardware and filled in the holes. I kinda like it as it matches the pipes look in a way.

i have one issue left but that was the fault of my ratchet is I need a replacement bolt for one of the end caps. I put the pipe back together and mounted it back on the bike after taking out the db killers. Then I took the end caps off to put in the bolts to fill up the holes. Somehow my ratchet over tightened one of the bolts to the point it seized. How. No idea. I just snuggled them the day before. So one bolt is not right until I get a new one.

I’ll definitely get a vid up soon. It’s definitely louder and deeper.I also have a servo buddy coming Monday for the exhaust flap delete which will make it even better (maybe).

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NocGSAR18

Discussion Starter · #15 · Jan 22, 2022 (Edited)

Made a quick cold start up vid today. It’s in a garage so it might seem a little louder than it actually is, compared to if it was outside. But outside is currently 15 degrees and a frozen wasteland so…someday I’ll get a test ride in.

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Noel61

· #16 · Jan 23, 2022

Looks and sounds good..... another idea I had (Fwiw) was to place a small round lead sinker in the hole and squash it so it mushrooms both sides and seals.

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AntTwon

· #17 · 2 mo ago

Apologies, as I know this thread is over a year old. I just picked up my 2023 and this is the only euro 5 scrambler example I can find online where this modification was done. I like your solution to closing up the holes with the hardware, but is there some reason people aren’t going with a pop rivet to close the holes?

I’ve seen one or two examples where there the open holes have resulted in the “whistle” which I definitely wouldn’t be able to tolerate. From the brief clip on cold start yours didn’t seem to have a whistle even without your hardware installed. Seems like there must be some threshold with hole size to avoid the whistle? Either way, I guess if you started with 11/32 and had to size up and do some clean up on a few holes I assume I could get away with the same. Would love it if I have the option to close up the holes and don’t need to based on a whistle.

Nice job and cheers from a fellow CT local

Chopper_Bob

· #18 · 2 mo ago

AntTwon said:
Apologies, as I know this thread is over a year old. I just picked up my 2023 and this is the only euro 5 scrambler example I can find online where this modification was done. I like your solution to closing up the holes with the hardware, but is there some reason people aren’t going with a pop rivet to close the holes?

I’ve seen one or two examples where there the open holes have resulted in the “whistle” which I definitely wouldn’t be able to tolerate. From the brief clip on cold start yours didn’t seem to have a whistle even without your hardware installed. Seems like there must be some threshold with hole size to avoid the whistle? Either way, I guess if you started with 11/32 and had to size up and do some clean up on a few holes I assume I could get away with the same. Would love it if I have the option to close up the holes and don’t need to based on a whistle.

Nice job and cheers from a fellow CT local

Pop rivets also have a hole in the middle....

AntTwon

· #19 · 2 mo ago

Pop rivets have a head on them with a hole on one side and the mandrel head on the other. It is not an open hole. They are often even waterproof. They would close the hole and also help give a finished look. I’ve used them on my bmw (car) exhaust to change exhaust tips.

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