After 500+ miles on my MB I can say a few things that should be changed/brought for a long trip:
1. Spark plug - they will foul/go bad eventually even with a 32:1 mix of good quality 2 stroke oil. Bring along another couple (I use NGK B5HS).
2. Clutch - it kept wearing out for me after about 100 miles until I figured out that you NEED to adjust the preload to the max. Especially if you're doing a lot of stop and start riding. A lot of people say "well just pedal and be super gentle on clutch" and "they come well adjusted from factory" but knowing China quality control I don't believe that they will last even using it very gently. After I adjusted preload to max, adjusted flower nut and clutch lever (need a tiny bit of slack), and sanded down/resurfaced the clutch pads so they loosely fit (so they can grip BOTH sides) I've had no issues whatsoever and it's as tight as ever withstanding that I ride it really rough (I don't pedal before I drop the clutch...). Also use some brake cleaner to degrease the flywheels as mine had grease all over it from the factory.
3. Brake pads - bicycle brakes, especially the cheap ones, aren't designed for stopping a very heavy bicycle (engine, gas tank, etc.) going at 30+ mph. Not saying that they can't, but it's stressful on them, meaning that they will require adjustment and brake pad replacement more often. Bring along some extras.
4. Chain/Drivetrain - be sure you have it on well and aligned properly. Also check the tension every 250 miles or so if you have the trash stock tensioner, mine became loose and suddenly came off one day; it was pretty bad as it got caught in my spokes and bent a few up. If you have the stock rear sprocket mount then be sure to either threadlock (I use blue) the bolts or check and tighten them every ~200 miles since they WILL come loose even if you torque them down well, messing up the alignment of your rear sprocket and causing your chain to jump off.
Finally bring along allen keys and adjustable wrenches...you know the stuff. Good luck!
