Import duty at roughly 5% $800.00
.
UK import duty on motorcycle is 15%
(BUT IF)
you are moving your normal home to the UK
you have had your normal home outside the EU for a continuous period of at least 12 months
you have possessed and used the vehicle for at least six months outside the EU
you didn't get the vehicle under a duty/tax-free scheme
you're going to keep the vehicle for your personal use for at least 12 months after it's imported
You don't pay duty.
Shared Insured container shipping from east coast USA to UK is approx $2000. (the bike has to be prepared for shipping)
Shipping to port from place purchased to northern East Coast USA from west coast USA around $800-$1000, from mid USA $400-800,
and from Southern USA $300-600.
That's only about 1/3 of it.
My advice, INSPECT THE BIKE IN PERSON ! Do not take anything for granted. You will need the Title of the bike In hand (VERY IMPORTANT), as the original will need to be sited by US customs, as well as the bill of sale. There is shit loads of paper work involved, and always headaches.
Once you do one bike, the rest get easier.