Loss of low end torque AR exhaust and removing exhaust valve.

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andrus54
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Loss of low end torque AR exhaust and removing exhaust valve.

Post by andrus54 » Fri Jul 28, 2017 12:28 pm

So I did what everybody raves about here. Ordered an AR exhaust with decat pipe and acra map. Was expecting more power and glorious noise.
After three days of riding, it seems there is noticeably less power in the low end.

Reading forums and other stuff I expected the exhaust valve to be just there for emissions but at least for me it seems ktm commercial is right that there is more torque low end with it.

My Rottweiler intake is on the way so this will probably help fixing it, but it seems I just spent 1500 euros and now hoping the bike will be as good as it was in stock form.

I admit bike looks amazing with this system.

But I wish I would have left it like it was.

Any ideas?

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Newjerseyduke
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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by Newjerseyduke » Fri Jul 28, 2017 3:33 pm

My opinion. These bikes are the best right off the show room floor. A lot of engineering goes into making one of these and bolting on parts isn't always an improvement.
In my case I just couldn't live with the stock exhaust note and backfiring so I held my nose and bought another full akrapovic system. I'm very happy with it and I do feel a slight loss in power under 4000. The bike is still fast but it did move the power up the tach and that's what a race pipe does. I'm fine with it because it sounds so good and let's be honest, I will never ride this bike to it potential. The reality is I could have bought another motorcycle for just what I've spent on 2 full akrapovic systems. Pre '17 Sdr s had a small low rpm torque loss. Post 17 with exhaust valve has to be more pronounced. If it ain't broke don't fix it. Hard words to live by.
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Rockbyter
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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by Rockbyter » Fri Jul 28, 2017 4:36 pm

If it ain't broke don't fix it
I think "if it ain't broke, fix it till it is" fits better.

Newjerseyduke
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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by Newjerseyduke » Fri Jul 28, 2017 10:51 pm

Now that sounds like me.
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Adoligy69
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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by Adoligy69 » Sat Jul 29, 2017 12:37 pm

This AR exhaust and Decat will have no Back Pressure ...these motors need some sort of back pressure ...

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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by Rockbyter » Sat Jul 29, 2017 4:52 pm

Fuelling should be set up for the back pressure and scavenging necessary. If the back pressure is wrong then fuel will be wasted straight out of the exhaust. More usual to find this problem with 2 strokes though.

andrus54
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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by andrus54 » Mon Jul 31, 2017 3:58 pm

Is there anybody here who has '17 SDR and has done mods that I have.
I feel I have two options now. Wait for two weeks till Rottweiler intake arrives, install it and pray it will be as good or better than stock.
Or put back the stock, sell the AR and return Rottweiler unused.

Which one you would do and why?

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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by Newjerseyduke » Tue Aug 01, 2017 2:18 pm

The smart guy would probably return to stock and remove the baffle from the stock slip on. I did that and it sounds good. Then bought a full system.

A guy online goes by the name royal Jordanian on you tube. He has a 17 and did work to it. I think he went full akrapovic system and is happy with it. So if 1 free flow exhaust works I can't see why another one wouldn't.

The new crop of bikes are hard to work on and when done it might suck. So each person has to weigh cost vs return on investment to see if it's worth it.
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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by Bagsweat » Wed Aug 02, 2017 2:10 am

Newjerseyduke wrote:The smart guy would probably return to stock and remove the baffle from the stock slip on. I did that and it sounds good. Then bought a full system.
You took the baffle out of the stock can on your SDR? Was it difficult and did you notice any change in sound? I thought you could remove the whole thing and it wouldn't change the sound (due to the cat restricting 99% of the sound)?

If it's easy to take out, I'll certainly give it a try. thx

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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by Newjerseyduke » Wed Aug 02, 2017 2:38 am

Sure did. It made it louder definitely. I knocked the rivets out of the end. Removed the end cap and baffle. Ground out the baffle carefully because it's used to connect to the internal tube that runs through the muffler. But patience paid off. It came out great. Few bucks for new tivets and done. It was noticeably louder.

I bought one off eBay for like 100 bucks. That way I wasn't butchering my stock one. Not sure if it was going to work when I started the experiment. But again your exhaust valve may change things.
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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by steve59 » Sun Oct 22, 2017 4:37 pm

Allright NJD i'm confused you now own a 2015 and a 2017 sdr?
Enjoy

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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by Newjerseyduke » Thu Oct 26, 2017 10:15 am

nope. all work done to my 15
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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by Newjerseyduke » Thu Oct 26, 2017 10:17 am

nope. all work done to my 15
2015 SDR 1290

andrus54
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Loss of low end torque AR exhaust and removing exhaust valve.

Post by andrus54 » Thu Oct 26, 2017 12:37 pm

Recap on mine as this topic resurfaced.
I installed Rottweiler kit 3 and it helped significantly. It now pulls at least as well as in stock maybe bit better.
Doing exhaust without Rottweiler does not make sense at all.

Would do these changes if I would have known in start probably not.
But it looks and sounds better than stock at least. But expensive upgrade for little better drive and lost my factory warranty.

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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by michaelnel » Thu Oct 26, 2017 3:45 pm

I put the full Akrapovic EVO system on my 2016 and am very very pleased with it. I do have a Rottweiler stage 5 kit on order but they are currently out of stock on the airbox, should be another week or two. But in the meantime I am delighted. I do have the Rottweiler fueling dongles installed to make the closed loop area happy.

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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by Fry » Thu Nov 09, 2017 2:03 pm

On my 2017 I have a Full Hi Mount AR GP1 System, Full Stage 4 Rotti Intake Kit, and Custom Rotti Map on a PCV....Brutal in every aspect.

Before putting on the Rotti Stuff, running just the AR kit, and after fixing a few issues I created, I never felt the bike lost anything with the addition of the Exhaust system and removal of the Exh Valve and Associated hardware.

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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by WarBaby » Thu Nov 09, 2017 3:13 pm

For reference, my 2017 mods are in my signature and I can detect no power or torque loss at any RPM as modified. Indeed, it is VERY obvious to me that my throttle response is sharper and available torque must be higher throughout the powerband as roll-on acceleration from just above idle is now outrageous. YMMV 8-) However, I can believe that removal of a 2017 cat/servo valve can produce low-RPM losses if the engine is not tuned for the changes in exhaust gas flow volume and velocity. Cheers!
`17 - BST carbon rims, Supercorsa tires, Arrow Ti can/mid-pipe, 16-T, Rotti 80/80 intake w/PCV/SAS/De-Canister/Servo Stopper/Fuel dongles, Lith. battery, R&G Frame/axle sliders, Evotech Tail Tidy/Rad guard/Exhaust hanger, LSL drag bar. -36 pounds.

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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by JAMSXR » Tue Nov 14, 2017 8:43 pm

I’ve got a 17 with an Akra slip-on with the baffle removed. Main reason for not going full system was inital cost and getting on track.

Currently the slip on is pumping out 97DB static and my local track has a 102DB limit.

As with most people, since buying the bike I’ve been toying with modifications, but the track issues has stopped me.

Spoke to a number of KTM specialists who told me to avoid stubby cans altogether, as they have a tendency to cause running issues.

To get my slip on running like a full system I’ll need the following... but if I go this route I’ll need to buy a track bike..

Arrow link pipe 71613MI
SLS Removal kit 61305922144
Dummy Plug 000700000KC02
Bracket (for compensating tank) 61613968044 £13.30+
Race Air filter
Akra map

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Re: Loss of low end torque AR exhaust and removing exhaust valve.

Post by mogas64 » Sun Nov 26, 2017 2:26 pm

Had a discussion with my dealer, as I have a 16 from new and wanted to de cat it, his mechanic has fiddled around with de cat pipes on his 1290sdr , the long and short was if you start putting aftermarket stuff on you really do mess up the fuelling, KTM spent a lot of time money etc getting it right first time, so all I did was junk the end can for an AR gp1r, nice and loud enough for me (I do have neighbours). Cheerio guys.
Current bike, 2016 KTM 1290 Super Duke R SE with private plate Fnarr Fnarr !!!

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