I did some of the basic mods a while ago (O2 sensor / KDX snorkel / clutch switch) which when added up did result in some noticeable, if mild improvements to power. However, my header pipe (standard exhaust) is damn hot which leads me to think it's running lean? So I'll try undoing the clutch mod and see if there is any difference, but I'm still looking to do something to get some extra poke on the trails. I guess the solution is something like a fuel controller?

 

You opened up the air intake with the snorkle so yes you need a fuel controller.

 

Silly question but shouldn't the EFi adjust the mixture accordingly?

 

Does it run better? If so, I'd recommend you look at the plug just to see if it's lean. May not be all high tech, but it would show lean, regardless. If it's lean the plug porcelain will have a whitish ash on it. It isn't hard to find the plug illustrations image on line. Look it up and compare.

I say that because you may have become more sensitive to the exhaust temperature as you perceive it, because you did the modifications. I ran into this sort of thing when I lowered my truck. It rode really rough and I thought it was due to lowering it... until I realized I used beams in the front, same stock springs and a flip kit on the axle putting it on top of the leaf springs instead of under, same stock springs. It always rode that rough, I just was sensitive to it now. Trailer tow package has stiffer springs. In the same way you may now be more attentive to the exhaust and it may really be running no more lean than before. Do take a look at the plug, can't hurt and they still fire the way they always did, so the burns should look the same too. Dark sooty if too rich (unlikely), nice chocolate powder brown if burning good, and whitish tan if too lean (entirely possible). Some old school can still give a hint.

 

Closed Loop function uses the O2 sensor to re-trim the fueling curve for closed loop operations. Performance operations are not "self correcting" and must be re-tuned with a tuner. Any defeating of the O2 sensor will delete the re-trim capability of closed loop operation.

Closed loop ops - cruising and light throttle
Open loop ops - heavy throttle, WOT, and high loadings at any throttle.

 

Sorry for the lack of knowledge, but what does WOT stand for? Wide-open throttle?

 

Yep. That's it.

 

Thanks, so my take-home from this is that it's not advisable to do any of these mods without having a fuel controller

 

You almost got it.
You can do the mods the membership use - which are dynobutt proven to create a good running KLX.
Or you can get a fueler, a dyno shop, and get your bike fueled correctly..

 

Plug seems ok to me, maybe a little worn out but due for replacement anyway.