I did that trip a couple of years ago on a KTM slightly under valued for Carnet purposes... no one questioned it at all, probably because £4000/£20'000 is so far beyond there understanding of money and the value of something it wont compute. When people (just normal locals) stopped and asked me how much it cost i always said $1000 dollars and they seemed happy and marginally impressed with that without thinking i am in the Bill Gates league, so therefore ok to chat to.
The only slightly amusing thing about questions is how they change.... the Iranians always asked 'how fast', the Pakistani's asked 'how much' and Indians asked 'how much to the gallon'.... cultural differences and priorities i guess.
Good luck on your trip i am sure you will have a blast.
Some day so soon....