I´ve never bought a bike in India, but you´ll probably need to get all relevant paperwork sorted there, before being able to export, and I´d figure that won´t be very simple in India. I actually remember reading something like its hard to get a carnet from India(?) But I´m sure you´ll get lots of good info about these here.
Regards carnet & SE Asian countries:
Thailand with a bike, no carnet needed or wanted. Foreign bikes are temporarily imported with their own permit, for 30 days, and I hear this can be extended to up to 6 months (we stayed less than 30 days).
Malaysia is in the system, but we could have probably entered without a carnet, entering from the main road land border with Thailand, nobody was interested about the bike at all. But we looked up the customs, and then got it properly stamped. So I´ve got no idea, if entering without it would mean trouble later on.
Indonesia requires carnet, even though I read on gt-rider. com about a guy, who managed to enter without one from Malaysia a couple of years ago, but not without several days of hassle & banging his head against the wall with the customs. During our trip, we actually heard several worrying stories about people being unable to get their bikes in WITH a carnet, so
it seems you need a bit of luck even with all paperwork ok. The cargo boat from Penang->Belawan seems to be one recommendable route.
Cambodia and Laos, Im not sure, because I´ve only entered them with bikes bought or rented from Thailand. For those, carnet wasnt needed, but maybe different, if registered somewhere else.
For China you probably wont need the carnet, but lots and lots of patience & dollars to arrange everything. Forget getting the bike into Burma or Vietnam.
You can get the bike freighted from several air- and seaports in India. Once again, the procedures are complicated, so allow up to a week to arrange everything.