all this dirt bike talk is quite amusing to me. I've raced on the amateur pro level for several years now and also have been a performance mechanic at a large local dealership for several years now. with that said the new 450 and 250 4 stroke bikes to require a lot more maintenance then a two stroke. look in any service manual and they will tell you to replace pistons normally 10-20hrs, crank shafts 40-60 hrs etc. even with a two stoke i replace my piston 15 hrs and cranks every year, due to the abuse it receives. I jumped on the 4 stroke wagon last summer and bought a new yzf450 and yes it was easier to go faster on but within one summer I went through two pistons and many valve shims which equals time and money especially if you cannot do the required work yourself. I'm back on my favorite two stroke again rm 250 and I can beat the 450's no problem but with the new ama rules for 09 i will be raceing against the 250 4 stroke bikes now which will be very easy. anyways 125's are good bikes to learn on and can be very potent in the right hands and are very cheap to buy now and maintain. basically don't get a used 4 stroke for your first bike because your getting what someone else has already pounded in the ground and will gernade and you'll be left with a huge bill for the engine rebuild also a 250 2 stroke is also a very bad idea, way too much power to get used too. id say get a 125 2 stroke or a honda xr of any size and ride that for a summer then move on. but i guess get whatever makes you happy but i hope you wear a quality helmet, boots, chest protector etc....
two strokes are only not being imported into the usa. they are still in production for the other countries though. suzuki and yamaha will still have them available here in the usa. also don't be to shy about that issue either because there is more then enough after market companies to buy parts from for them and also the manufacture has to carry and make parts for 10 yrs i think past the year of the model. buy what you can use at this point and ride the hell out of it till you need something better! I've seen to many kids get what is "cool" and get hurt really bad. its not too cool laying in the hospital