>>1008030If your bike is going to be your primary mode of transport, you should take your time to find something that fits and is in OK shape for long distances, and you don't want to waste your time on your trip searching for a good bike, nor do you want to be saddled with a piece of crap that doesn't work well.
Getting your bike in shape, all your gear mounted, and doing some testing ahead of time is key to a good overseas bike touring experience.
FWIW, flying bikes to Japan was super cheap.
>Can I take a bike on the trains and buses?Depends entirely on the country, friendo. You haven't given us enough details for a meaningful answer. You should do some legwork and research of your own beforehand.
In Japan, bikes were fine on trains and busses IF AND ONLY IF the bike was partially disassembled and packed in a Rinko bag.