Ok, just a few random observations on the 2 bikes for sale...
The KX is 2 years older than the KDX, yet costs $200 more.
The ad says it still has the original tires on it, yet it has all new plastics.
That leads me to believe that it isn't as "low-hour" as the seller would like buyers to believe. It's pretty hard to wear out/thrash all the plastics without wearing out stock tires. I have bought a few new bikes that came with crappy stock tires. They come off immediately, replaced by tires that actually work. The stock tires sit in my basement til I'm ready to sell the bike. Not to say this is what is going on with the KX125, but just something to think about since you're fairly new to the dirtbike-buying game. Look at the footpegs. The teeth on them should still be sharp if the bike has low hours. Also, is all the paint worn off on the frame where your boots rub? Does the shifter/brake lever still have the cross-hatch marks on it? And what about that after-market pipe? Does the seller still have the stock pipe?
Also, 2-strokes don't get "tuned up." At the very least they get new rings, but most likely it will need a new piston also. The 125 motors, by virtue of their natural characteristics, tend to be high-stress motors and will need more maintenance more often than the KDX 200 motor. If your guy is into mellow riding, you will probably be going through spark plugs regularly and having to re-pack the silencer all the time. 125's were not made for "mellow" at all.
I've been riding 125's for over 20 years (I rode them almost exclusively for 14 years) and I can assure you that they demand more attention than a larger bore motorcycle. I would be
very cautious and extremely picky if I were in the market for a 15-year old 125 2-stroke, and I would be ready to replace the piston and rings immediately upon purchase. I would also take someone along that knows how a properly set-up 125 2-stroke should run.
As far as the KDX goes, you are looking at a bike that has stood the test of time. I can guarantee you there are a lot more `97 KDX's running around out there than there are `95 125 2-stroke motocrossers. The KDX is 2 years newer and is $200 cheaper. It will be easier to learn on, will take you farther into your riding career, and will be a lot less maintenance-intensive. I've ridden several KDX's and every one of them has been a joy to ride. Way more fun than would be expected, and a hell of a lot easier (less work) to ride than any 125 I've ever owned. They will scream like a motocrosser if you wind them up enough, yet they'll happily chug up the gnarliest hills in 2nd gear easy as you please. It will be much easier/cheaper to modify to your personal needs, as there are zillions of pre-tested mods out there for the KDX, and entire websites dedicated to getting all you can out of them. Check out
http://justkdx.dirtrider.net/ for a glimpse into the world of KDX. While you're there, take a quick gander at the classifieds and I think you'll see that the KDX in your ad is a pretty good deal.
Not knowing anything about the actual bikes in question, if I had to choose between them right now, there is no question about it: I would go with the KDX.
WoodsChick
