As per above post. Sorry but quick Motorcycle travel will not be cheaper than public transport. And you'd want a lot of motorcycle experience to do the trip. Or at least a lot of life experience. Without either of those then I'd so no again.
Consider you will be flying in and out. And for cost reasons you want to fly in/out of 'hubs'; these being where airlines start/terminate their flights, so you won't be having a stop over where both you and the baggage may change planes = $. Paris might be cheaper than London, consider the transport costs London to Paris.
Then plan what you want to see. Or do.
Then fit in those places by transport. Eurorail can be cheap - particularly when purchased overseas and for some time period. Eurorail will do you eastern europe.
Where to stay? Youth Hostels. Cheap and they have cooking and may have washing ... And they have similar people to talk too, and pass on information. Like cheap things to do, places to see.
Plan on having at least every 7th day off. You'll need to do stuff, like washing, phone home, rest, and so on. So you want that 7th day to be in the same place.
Unless you want a very slow trip ... no. They are difficult in the airport... some buses and trains won't take them.. Unless you want to use the bike for substantial parts of the trip, NO.
Not certain? Get some experience in touring on a bike. In your local area, a weekend overnight not far from home camping out. Take a bicycle. The equipment is similar for a motorcycle. If you like that then consider getting a motorcycle licence. Take a learner course, even if it is not compulsory. Here the local post office found training their drivers saved as much money as spent training them (if not more). And that was for the motorcycle riders on 110cc bikes. They then turned around and trained all their drivers.
Above all this.
GO! It will open your eyes.
Eurorail for western Euope through to Turkey. Then back.
TransSiberian for Russia. Cantake you through Mongolia to China.
The fly back to the 'stans.
Fly to say India, train there. Fly Thailand, bus around.
That would be about the easiest... flexible ... and probably cheapest.