New bike in the garage...

[ford832]

You realize of course that if I say one thing and all the experts say another-that I'm obviously right but yeah,I always see that recommendation as well.  
Truthfully though,I'd do as I did-for these reasons:

For max power you'd toss them both,for the most power while being quiet-change the pipe.For good power that doesn't alter the bikes manageability and character unless twisted and good  durability,change the muffler.
The muffler has no packing but is a mechanical.(automotive type)
The pipe doesn't bear that much resemblance to your typical expansion chamber and loses power because of it-BUT-it is far more tucked in than anything you'll replace it with,is made of heavy gauge steel and moreover than that-it's double walled and virtually indestructible-and I'd be loath to toss it.
If you enjoy the character of the bike at woods speeds as it sits but would like to be able to hang with your buddies when the trail opened up,I'd go with the mods mentioned above(reeds,box lid etc).I guarantee you'll be real happy.FMF Q is what we put on my bro in laws.

[SachsGS]

Ford if you keep on like that ("I'm obviously right") you know you will have your day pass privileges revoked!

[ford832]

Oh come sachs,throw me a bone.I'm never right at home.At least let me think I'm right somewhere-once maybe Now then, must go check myself back in before I'm missed

[Coop]

 

I am going to do some suspension work, and maybe a few little power "mods" over winter. I am seriously considering the Rob Black head and carb mods. I hear they really open up the KDX. I don't know how soon I will mess with the exhaust because I love how quiet it is. I am a proponent of quiet bikes. Makes it nice when I get antsy to ride and hit the few short trails around the neighborhood. I live in a small community in the woods known as "Bear Rocks". It used to be a ski resort and most of the houses here were camps, chalet's, cabins, (whatever you want to call them) back in the day for the richy ski folks when they came up on the weekends. You can still find the lodge and slopes if you go exploring.

If/when I go with an after-market exhaust  it will be an FMF 'Q' Silencer/SA and a "Woods" pipe.

[SachsGS]

I've ridden modified KDX's over the years and sometimes wonder if it might have been better just to get a Gas Gas or KTM 200. I think the KDX is an excellent machine (and I can't understand why Kawasaki discontinued the bike) but I would be cautious of "pushing the bike outside of it's design parameters". The euro bikes come stock with more rigid chassis, higher spec brakes etc. and might be cheaper and better in the long run if you go the performance route. I do understand that if you are a Kawasaki fan the fun in modifying the bike.

Ford, my better half is great but I try to keep, at all times, at LEAST a 1000 km's between my mother in law and myself! Life is vastly more peaceful then.

 

[Coop]

I think Jeff Fredette proved for years they can be raced at pro levels 

But of course if I find a 1999-2002 KX125 rolling chassis I wouldn't turn it down for a KX-DX Hybrid build 

[ford832]

The KTM's and Gassers are more hard edged but when you've beaten yourself to death and just need to sit down and limp towards the finish,there's few more comfy places than the seat of a KDX.

[SachsGS]

All Maico pilots are Olympic caliber warriors, please explain this concept of "sit down and limp towards the finish line"? 

[ford832]

All Maico pilots are Olympic caliber warriors, please explain this concept of "sit down and limp towards the finish line"? 

No problememo; First you need to start with a bike that has a hope of at least getting off the start line.Once you get that far let me know and I'll gladly explain the finish line part.

[MyckMcClung]

dude gold valves, spring, a pipe and spark arrestor, and that thing will be the best trail ride since, well your bike with those mods.

[Coop]

Haha yeah as I get the cash I plan to do work on setting it up nicely. For now I am broke and just plan to jet it properly, and replace the fork seals and oil (shock too).

I pulled my forks the other day so I can replace the oil/seals, pulled the pipe so I can clean and paint it (I can't afford a new one anytime soon), and pulled the carb so I clean and re-jet it. My back was really bothering me at this point so I only go the stuff taken off and then I had to quit. I want to pull the triples to check/grease those bearings, as well as pull the shock and swingarm to get those bearings. This bike shows signs of some neglect as far as this type of maintenance goes so I figured now is a good to time to tear down and replace anything needed.

I realized the snorkel has been removed from the airbox and it is jetted rich: 160 main, 48 pilot, and 1172 needle in middle slot. No wonder the plug was so grungy.

[MyckMcClung]

you probly threw out your back picking up that muffler, it and the pipe together weigh 50lbs.
 The 220 was created so that KDX guys can run in the 250 open class legally. I has just a little more oomph in the low and mid.
The FMF Gnarly Pipe and Q are a great choice for this bike Coop, I know a guy that has that setup on his 200, he's real happy with it.
  my riding buddy has the 220, he put the PC2 and PC sparkarrestor on it, great performance, I ride it all the time, before and after the install, it friggin rips now, still really quiet, I hardly noticed the difference in sound output, but that might be because he's always eating my dust,lol. He also installed the race tech gold valves, man let me tell you how much better that bike is now.(Speechless)
 I put the Q on my Daughters kx100 it is really quiet.
Of course I bought the T2 for mine before the Q was out.

[factoryX]

I bet a kx125/200 is looking real good right about now...

I so want one..

[MyckMcClung]

Dude that's sweet!!!!! is that a 2004 kx125 frame, w/ 2011 front plastic? More pics pleeeeez!!!!

[factoryX]

not mine, found it off of google, it was the only pic of it on there or I would have "borrowed" more..  
Found a thread on more builds including that one I believe:
http://www.dirtrider.net/forums3/showthread.php?t=163605