It really is a bit ambitious if your new to biking, but if you are going ahead with it then look out for:
the adventure motorcycling handbook, biking abroad, and the essential guide to motorcycle travel tips. The last one is very good, but all worth a read and make good reference books. They are all paperback too.
Have fun and good luck, and dont forget the insurance small print.
look in the rideout section on here to read what people have done or are planning, you should be able to do Istanbul no problem just allow plenty of time because if you not used to riding or even driving a long way in a day, you will have no idea how tiring it is concentrating for long stretches at a time, plan your route carefully as well but if I remember its a fairly straight forward route down to there via the baltic countries, use googlemaps very good they are.
Istanbul is not so difficult, it’s just a long way, but asphalt* all the way, if you don’t get too ambitious.
Your biggest single problem is going to be getting (the right) insurance. If your going to use it, make sure it covers Switzerland. Lots of policies only cover the EU and CH aint members.
*You might get a different perspective on “asphalt” in the Balkans. They do that very badly, along with lots of other things.