I've had a DNA filter on the work bench for a couple of months,finally fitted and gave it a run,still has the stock filter and Akra pipes with the baffles in,pick up great mid range even better,but even with the smallest run to 90 on the clock,the motor really got it's nickers in a twist,which showed all the signs of running lean,to the point were it all be cut out,and I had to nurse it home till it picked up after some steady riding.

Now I've been around the block figuratively speaking bike wise so fitted my fair share of filters and Power Commanders,but these symtoms seemed pretty extreme to me with just adding a stage 2 filter or is the norm.

http://www.xt660.com/showthread.php?t=12547

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2008 XTR Mods : DNA Stage 3 Airbox, PC111, Carbon Cans Ovals, Steve Ruth built XTR734cc Big Bore with - High Desert Dyno (HDD)/ Cuervo Racing Gas Flowed / Ported Head fitted with +1mm Valves & uprated Springs, HDD 5050 Camshaft, HDD +3mm Throttle Body, CP 105.5mm 11:1 Piston, Custom Mapping, Piasini ECU, Renthal 613-01, Barkbusters VPS, Pivot Pegz, Touratech Bashplate, Foam Grips, Kev's O2 Sensor Mod, Kev's Extra Coolant Cooler, Wilbers Progressive Fork Springs and Rear Shock

What would we do without richardsracingbonkers and Kev, aye?

Thanks Richard for pointing the man in the right direction

Thanks for that,but it's telling loads and yet telling me nothing,I was aware that fitting the stage 2 would lean the bike out,and hence why I didn't touch the snorkel till another day,and I appreciate that to get the bike to run well I'll need a PC,but shorely it shouldn't run that badly on a run with just a stage 2,or do they??

Or am I missing something!!

well ok I'll tell you in a nutshell

[nutshell] When fitting a DNA stage 2 it is recommended to fit a fuelling device, A kev Mod or a more expensive Power Commander. PM Kev for details. [/nutshell]

Thanks,I've encountered bikes running lean,but I guess because it's a single high lighted more,one things for sure the stage 2 is being taken off till I sort something out,thanks again.

yes..you are not reading the end part of the thread...!

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2008 XTR Mods : DNA Stage 3 Airbox, PC111, Carbon Cans Ovals, Steve Ruth built XTR734cc Big Bore with - High Desert Dyno (HDD)/ Cuervo Racing Gas Flowed / Ported Head fitted with +1mm Valves & uprated Springs, HDD 5050 Camshaft, HDD +3mm Throttle Body, CP 105.5mm 11:1 Piston, Custom Mapping, Piasini ECU, Renthal 613-01, Barkbusters VPS, Pivot Pegz, Touratech Bashplate, Foam Grips, Kev's O2 Sensor Mod, Kev's Extra Coolant Cooler, Wilbers Progressive Fork Springs and Rear Shock

In fairness I missed that last bit,sorry don't agree in my case,and I've still got the snorkel on,I've another bike that I ran for years,open cans,filter and induct on par with the stage 3,and got away with it untill I fitted a PC,but this XT ain't going have it,thats for sure.

But thanks for all the replys.

Running your set up at present I would expect the A/F ratio to be around 15:1, which is lean. If the bike runs fine without the stage 2 filter then you would assume that with the stage 2 filter the A/F ratio is to lean.

Do you have a fresh tank of 95 RON fuel in the bike?

I would refit the air box cover & retest to see if the bike still runs fine. If it does you need a fueling device to correct the A/F ratio. If it doesn't then something else is wrong.

The XT produces it's most HP & Torque around 13.2:1.

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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