hey guys,
later next week I will be fitting some Procircuit T4 pipes to the xtx. One of my pipes (the one with the sensor) is badly damaged.
The workshop who will be fitting the pipes will knock me up a set of headers as well. My question is can they leave the balance pipe out?

is it really needed?
the T4's will be straight through so may be a bit loud but thats fine by me.

has anyone else done this on a set of loud pipes? does the sound sound any different or did you have any problems?

thanks guys...

Get rid of the H pipe & fit a Y pipe, the Y pipe design gives the motor better throttle response, runs quieter than no link between the pipes or H pipe, the Y pipe gives better exhaust note synchronizing.

__________________
Click here to join the XT Supporter's scheme

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

Thanks for the advice Kev. I have a metal mule pipe with 2into1 (dirt bike type) headers on a different bike. I can see here the flow would be more uninterupted than a H design.

On the bike I'm working on now, If I ran the standard design headers but delete the H pipe under the engine, would the Y form under the engine for a couple of inches then branch out into two (around the bash plate mount)? only problem I can see here is a lack of room.

It may be better to design a pipe more like the (dirt bike) 2into1 and run 1 big pipe. Only problem here is the shops here dont mandrel bend. They cut and TIG weld preformed bends. I had a single T4 muffler on a KLR650. sounded mean as anything. quite loud but I liked it, so it would be pretty much the same sound on the 660.
[IMG] [/IMG]

Having the 2into1 Y would be an advantage as it would form so much easier under the engine, then just run off to one side. I think it would be less technical for the locals to build rather than a dirt bike styled 2into1.

I'm setting the bikes up for tours here in Asia so the single pipe option would be better as I could then run a solid side case on the opposite side for storage.

Im still trying to decide the best way to go so any input would be good.
Just one other question Kev, can I delete the O2 sensor (maybe with the addition of an o2 eliminator) or is it a crucial part on the 2010 model?
thanks Kev...

The resistor type O2 eliminators don't work on these 660's, I used to build an O2 eliminator that could turn off the closed loop circuit but no longer make them as the mod died off.

These days my O2 controller is what you need to control the closed loop A/F ratio, or one of Dynojets O2 optimizers.

__________________
Click here to join the XT Supporter's scheme

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