Hi Mortis - here is some info I posted on XT660.com for someone asking a similar question - hope it helps:
Certainly if you are going for more than a few weeks, then it is cheaper to take your own bike than to hire - and of course you won't be limited to where you can ride (hire companies don't tend to like you going seriously off-tarmac, for obvious reasons).
The other option is to buy, but that is a whole other thread (or read the June 08 issue of TBM magazine, ahem).
So as a quick FAQ for anyone else considering heading to the US with their own bike:
• Someone like Motorcycle Express can handle all the shipping (by air) for you, but it will cost around £1000 (each way).
When I brought my XR650 back from the US last year (using a local US shipping agent - you tend to use an agent in the country you are sending from btw.) I paid around £700, but had to build my own crate.
This year I used their opposite number here in the UK - a company based in Manchester called Air&Cargo Services Ltd. Unfortunately due to fuel prices and the exchange rate, the cost is closer to £1000 now, especially as the US customs dept. seemed to want more for clearance than the UK do...
• As a 'tourist' machine, you won't have any tax or import duty to pay, but you need to make sure the authorities realise it is not a permanent import. A letter stating as much to your shipping agent will suffice.
• A carnet is not required for the USA.
• Insurance is available for foreign machines and foreign licence holders (not all US companies will insure you without a US licence) through Progressive.com - one of the largest insurance agents in the US. You can pay monthly (but you will need a US bank account for direct debits, see below) and you can cancel your policy at any time.
Vehicles in the US are insured on the VIN number, so your (foreign) registration number is irrelevent. Easy to apply on line with Progressive, although it may be easier to deal over the phone as your VIN may not show up on their computers, and especially if it is not a model available in the US (like the Tenere for example). You can also apply for your insurance before you go, and set the start date of the policy for when you get there. However, you can always do it once you arrive as cover is instant.
NOTE. you will need a postal address in the US to get insurance with Progressive (or any other I imagine).
• You do need to carry your insurance certificate and a copy of your V5 registration/ownership document (best to have the original too) with you at all times on the bike.
OK, that is pretty much it as far as paperwork/shipping is concerned... other info you might find useful:
• Helmets are required in most States (and you will almost certainly get pulled on a foreign machine without a helmet, even in those States were it is legal). Also, most States don't allow you to 'split lanes' (ie filter between traffic), although it is allowed (and often necessary!) in California.
• Speed limits are typically 25/45/55/65 mph (compared to our 30/40/60/70), there are no gatso's (that I've ever seen), but be aware that roadside patrols have radar guns.
• Fuel is (now) around $3.50 a gallon - yep, still less than £2! Petrol pumps in chain gas-stations are all debit/credit card pay-at-pump type, although you can pre-pay inside with cash (a bit tedious with a bike, especially as you are bound to pay more than you actually get in the tank!). More rural gas stations still have attendants, and typically prefer cash.
UK debit cards don't seem to work in petrol pumps (they don't recognise the PIN number), but credit cards tend to as they don't use the PIN function.
• However, you can easily open a bank account (for a debit card) as a non-resident at Wells Fargo for example, but like insurance, you'll need a US postal address.
Otherwise the country runs on plastic (even for purchases of a couple of dollars) and your UK cards should work in ATM machines with no problem if you need cash. But remember that most UK card issuers charge a fee for foreign transactions, so it's probably worth getting your own US account if you're staying for a while.
So, what are you waiting for?!