What I want to know is what passport your under to be able to pass all those borders on a dirt bike?

Diplomat? Govt.? Military?
Honda have re-designed the top end/head on the CRF 450 four times since it first came out four or five years ago. The Ti exhaust valves are gone and the seats have been redesigned for toughness. Reliability is MUCH improved over the eary bikes, whose valves did tighten up causing major damage. Several dirt bike riding buddies own or owned these bikes, all X models.
This bike has been a MAJOR embarassment for Honda, probably the first bike in
40 years that caused such problems so early. Reports from local racers say the last couple years have shown no problems with the CRF's, X's or F models in competition conditions.
Having said all that....this is, IMO, NOT a good choice for long distance bike.
Can't carry much luggage, will require frequent oil changes...and even then
the service life of this SUPER hi revving, hi horse power RACE bike (for those who really have no idea what this bike is) will not be long enough to do 1000's of miles across deserts unsupported.
Other good alternatives have been suggested. Here is my list of bikes that are OK in the dirt, reliable, can carry some gear, have some aftermarket support for a better seat or bigger tank. All things you should think about.
1. DRZ400S (S for stronger rear sub frame) Lots of accessories.
2. XR400 (kick start) Not much support for this bike now but stuff still around.
3. WR250R Yamaha (street model, strong rear subframe, bulletproof if a bit under powered. Not much aftermarket...it's just come out)