I have gutted my exhaust i belive i have to set the c01 setting, i have ridden my bike and all seems fine, no perforamnce diffrence that i can fell just a lot os back firing?

Refer to the thread "fuelling fix" from the list you get once you click on my signature with the list of mods.

Good luck

I had a look at my Co after gutting my exhaust they were at 4 i was told to move it to 25, how do i know what is the correct Co, what do i look, listen or feel for?

Adjusting the Co will only adjust the fuelling at part throttle (part throttle is when the throttle is closed to slightly open around 5%) Anything past 5% you will need a fuelling device to increase the fuelling.

You might expect to see a slight increase in HP but not much with this conversion by it's self. Your need to combine mods like stage 1 & 2 DNA filters fuelling device & open cans to feel any big HP gains.

Did you gut the cans by just removing the catalytic or did you remove the catalytic & baffle them??

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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 /
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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

Took that cats and baffel out, so shoul di just,leave it on 25?

That may help, but as Kev said, only at small throttle openings. When you mess with the exhaust it changes the mixture all the way to full throttle and you can only adjust the rest of it with a Power Comander or similar device. Your bike will probably produce less power than it originally did and just make a lot of noise. It may also damage your engine due to overheating.
By opening the exhaust or inlet you allow more air in than was originally planned for. This will make a bike that was designed to run lean for emmission reasons to run even leaner. There is only a small range of fuel mixtures that will let an engine work efficiently.
You need to provide more fuel through the whole throttle range and that cannot be done without a Power Commander or similar device.

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