My 2009 XTX with Akrapovic SP was too loud with the Baffles out and not running well enough with them in.

I had incresed CO2 by 6 and I have replaced the Air filter with a K&N stage one - I didnt want to do any further obvious things such as a power commander or drilling the air box as I was losing faith in the bikes ability to run well enough for my needs.
Having seen that Gianni had modified his Akrapovics I have been experimenting with mine and I am delighted by the results.

My bike has the O2 Sensor by the way and the AIS which have both been left alone and stock.

Hopefully people will find the details below and the pictures useful in deciding whether to attempt this mod - if it all goes wrong you can buy replacement Akrapovic Baffles for about �37 (GBP) each


So above is the bike - Nice eh?



Look into my eyes.... - the Baffles are the bits in the centre of each slencer, they are tubes with a mesh at each end that slows down the exhaust gases as they try to exit the exhaust.
By slowing the gasses down they create back pressure and smooth out the bangs and pops from the combustion process (make it quieter) but they also stop the engine breathing so well as the back pressure stops the gasses clearing the cylinder so quickly. Try breathing through a straw and you will get the idea!

We are going to modify the baffles to reduce the back pressure and help the engine breathe better whilst not making it too loud.



First remove the rubber bung from the bottom of the silencer, this allows you to get to the hex head screw that holds in the baffle



Put your 4mm allen key up inside and undo the screw, if you drop it inside the casing you will have to shake the bike about until it falls out - so do it slowly and dont let your hands shake!



Phew! - I got it out in one go - this is how you have to put it back in by the way - the screw is not Magnetic so if you have shakey hands you might want to use a bit of Blu-tac on the end of the Allen key to reduce the chance of dropping it.


Now you have to get hold of the end of the baffle and ja ja jiggle it until it comes loose and you can pull it out - mine came out easily but you might have to use grips to pull them if they are stuck in there a bit.

Once you have them both out, your off to the work bench to do some cutting!



I cut about 15mm off the end, I guess if you cut more off then the pipe will be louder, of you can also make it louder I think by drilling out the holes in the mesh as Gianni has done.



Heres one I cut earlier, I found Praying made a difference to the process - any denomination can do this and it seems to work.



Here is the bit I cut off each side - the holes in the mesh are what are slowing the gasses down too much - I now only have the mesh in the end of the baffle that shows - so I have halved the resistance and the exhaust still looks like it should to anyone inspecting the bike.



Now the baffle goes back in - I found a good way of lining up the screw hole with the hole in the silencer casing was to use an allen key and push it through them both and wiggle it to line them up.



The screw goes back in to hold the baffle in place - fiddly and nerve wracking in case you get it cross threaded - but eventually it goes in and your almost finished......



Put the rubber plug back in and in Homage to Kev make sure that the emblem of the hammer and sickle are both facing the right way and straight.



Now start it up!

I found that the surging has all but gone, the engine has more power and is so much smoother - its actually fun to ride again.
The noise is not too bad and all in all its well worth doing.

I have pasted a video below of the bike without any baffles that doesnt really sound as bad as the real thing - its unbearable in real life and is irresistable to the Police when commuting in London Traffic - but you might like it!

I have found no difference now in riding the bike with the modified baffles and no baffles at all - other than my neighbours are now talking to me again! I found that removing the Baffles increased performance which is why I started to experiment.

Enjoy

Robert

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My other bikes as smooth as silk, my fun bikes a thumper!

Good work !!!!!

Ciao.

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Mess with the best, die like the rest.

Thanks Gianni - I wouldn't have done it without your original posting

Robert

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My other bikes as smooth as silk, my fun bikes a thumper!

Nice work mate, neat & easy job.

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Mods that I have done to my XTX's

My 04 XTX
Stage 1 & 2 DNA filters / Kev fuel mod / snorkel mod / Drilled air box mod / Engine breather mod / Fork Spacer mod / 15w fork oil /
[
My 07 XTX
Raptor 700 cylinder 102mm / Modified Crank Case to take a 105mm Raptor Cylinder / 11:1 102mm JE Raptor piston / Stage 1 Raptor Hot Cam / Ported head / Colder Spark Plug / +2mm Throttle body / DNA stage 1 & 2 filters / Modified Air Box / Snorkel removed / Worry Brothers stage 2 filter cover / 6mm & 8mm Bolts Replaced with Titanium Bolts / Recovered seat in Black / O2 Eliminator /

My 09 XTX
59HP at the rear wheel / Stage 2 Raptor Hot Cam / DNA stage 3 Air Box / Carbon Can Exhausts / Modified Exhaust Link Pipes / PCIII With Custom Fuel Map / Wideband Commander O2 Data logger / LCD100 Dyno Jet display & fuel adjuster / 2500 OHM HT lead instead of a 10K OHM XT lead / Extra Coolant Cooler / Protaper Fat Bars / Tail Tidy With LED Tail Light / OKE Protection Knobs / LED indicators / AIS blocked / Modified rear sprocket rubbers / Rear Foot Pegs removed / 09 ECU With 02 Sensor Changed To A 06 ECU / Complete wiring harnes Changed from 09 to 04 / Home made LED resistor flasher / Hole drilled in the fuel tank filler neck to allow quicker filling / Modified Bar End Weights / Progressive front fork springs, 15W fork oil, forks lowered 25mm, used XTR rear links lowering the rear 20mm, rear spring one click stiffer / Changed front & rear guards from blue to black / 47T rear sprocket / Speedo Healer V4.0 / Kev throttle cam mod / Throttle grip mod / The new 2010 O2 sensor mod is out, works a treat, The new 2012 O2 Controller is out, PM me for details

Now ride a 2018 MT09SP ABS + TCS

My KTM 990 SMR Mod book. http://www.ktmsmt.com/viewtopic.php?f=13&t=4946

stupid question but some one have to ask it.
could it be done river sly ? what i mean, would it have same effect if we leave bottom end stock and somehow cut top part of db killer ? i don't have anything against its functionality but i do hate that net look...can this be done ?

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Yes you could reverse the process and remove the mesh (net) from the end that you see - it is tack welded in so you could either drill it out or cut through the welds and remove it that way.

If you are going to do that though you might as well just take out the DB killer and have the bike look and sound evil!

Robert

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My other bikes as smooth as silk, my fun bikes a thumper!