Joe, go big or stay home
 

May be an odd way to start off with a reply but this is from experience... I commuted on a 175 cc machine when I was a kid. Now I waste some serious saddle time in North America, actually Canada and my machine, slightly over 100 HP is a midweight and I use every one of them...by times. How big is London? Let me put it in perspective. You can put the entire United Kingdom in the Great Lakes and still have room to do some serious fishing. Canada itself is just shy of ten million Square miles. Do yourself a favour, get something that will reliably do 600 kilometres a day in comfort. Suggestions...Theres a ton - 0 - Jap bikes that are cheap and would fit the ticket. Personally I would look for an older BMW K bike and go have the time of your life. Don't fudge the paperwork either. That stuff is just way to easy to figure out. If a white knuckle buzz hour after bloody hour is your idea of fun then you'll need a shrink by your third day.

Stu, he had stated doing the trip over the course of 5-6 months in the first post. I think everyone, including you, has good advice, but with that amount of time, he will be able to see the US on a bicycle, let alone a small displacement bike. Dave Smith mentioned he did a long trip in Australia on a slower bike and loved it. The trick is to stay off the interstates, unless, again as Dave Smith stated, you really want to see a McDonalds and Wal-mart often.

The advantage of finding a small displacement bike is that they are fairly abundant. Many people in the US buy Yamaha Virago 250's in order to get seat time while they are learning and striving for the proverbial 1100cc or larger cruiser. When they get their cruiser, the 250 is sold off as scrap (personally, I would keep it as a back-up considering that trade-in or private party sales don't net too many $$'s, but that is just me. Plus it allows someone to get a really good deal on one, again, that is just me).

A couple months ago, someone on a Chinese bike forum site I belong to rode his Lifan 200 enduro from Louisiana to Florida in 14 hours, and said that he rode it on the interstates at or very near the speed limits. Yes that is about the extreme of it, but all the talk about it having to be a big bike or nothing, especially considering the time he has and the alternative routes available to keep him off the interstates, shows that a small bike is doable; and doable even in the US!

But again, if a newer KLR 650 can be found for $2000, and the budget allows it, that would be a good alternative to any small bike

Funny thing: back in the early 70s my father rode across Canada (From Vancouver to Halifax) on a Yamaha 175 - with my 8-year old brother on the back.

Road conditions have sure changed since then, so a bigger bike would be far preferable, but a small bike wouldn't be so bad. I think something like a 400 through 650 would be just fine.

i, too, think the klr 650 is a great choice, personally. and cheap+easy to maintain. you might want to improve the seat for your trip...

it will also allow you get around on old fire roads and drive along riverbanks if youre interested in seeing more than the highway - while it handles the highway equally well

if you want something smaller... i dont know. suzuki, kawasaki, and yamaha all make smaller enduros... but if youre going to be on the highway, i wouldnt do it

hope you have an amazing time. i think you will be pleasantly surprised at the cost of riding and maintaining a bike in the usa if you do the work yourself and buy a reliable model

Small bike
 

Considering that you will want to keep up with traffic, even on small roads, I would not want anything smaller than a KLR650. I have owned one for several years and with a good 50/50 dirt/street tire it will work well on dirt roads and up to 80mph you can keep up on the freeways. But past that you want a real street tire.

Buy anything smaller than a 650KLR and you won't see much of the good old USA, you will be too busy looking in your rear view mirror.

There are actually many side roads that one can take through the US. We "locals" like to want to get to a destination, so the (often brutal) freeways and interstates are taken. There are some people who have literally months to get through here, and while a trip from L.A. to New York can be realistically done in 3 or 4 days time on highways and interstates, those people can take back roads to get to the same destination in a 2 week period. To each his own, and I would personally want a KLR 650; however an old 90's DR250s could do the trick, too.

If you look around on the forums here, there are some posts from two Europeans who rode from Alaska to Argentina on a couple of Honda Cubs. They wrote that their cruising speed was 70 kph - about 40 mph. I'd have thought that they'd be run off the road going through the USA that slowly, but they said they just stayed off the Interstates and had no problems at all.

This is all very well
 

... but you'll still need to register it once you've bought it... in the States that involves 'buying the plate'. Over here of course, the plate stays with the vehicle, but even over here you need a residence to register the thing.

Bicycles run on back roads so drivers are accustomed to seeing some slow moving objects. :)

If I could not run at traffic speed, I'd want an orange flag on the bike and a bright reflective vest on me.

It depends on the state laws. In California, the plate comes with the vehicle. I've let a couple people use my address for registration. It's not a problem (at least in California). Other states vary and the plates stay with the owner.

--Dave

Some States have minimum displacement requirements for getting on a freeway. While such roads are not terribly exiting, they can be handy in some areas.

Califonia, for instance, defines a bike with fewer than 150cc (149cc and smaller) as being a "motor-drive cycle," not a "motorcycle." If they won't let you on the freeway, then there is another road that you can take, but you may be trying to use 30 minutes on a freeway to miss 3 hours of city traffic.

For this reason, a 125cc may limit your options. I have done some nice trips on a 250, though if I hit a headwind on a freeway section, I had to stay in the slower lanes.

All things considered, I doubt the displacement limits are enforced unless you are being an obvious hazard, but it did seem worth mentioning.

Matthew

I do nearly all of my biking off the motorways, mostly on old abandoned D roads here in France. But.... I would want a bike that gave me the option to cope with the motorways as sometimes that is far the best way to either negotiate a bottleneck or allow you to guarantee an arrival time, such as when you have to catch a ferry.
Years ago I used to ride a Triumph tiger cub 200cc single with 10bhp. I could happily go anywhere in The UK with it. Then they built the motorways... I would not be happy cruising at 45mph on a motorway. Times have changed, and the bikes have largely changed to match the new roads and also changed from cheap transport to recreational vehicle. Also a major change is complexity of bikes and communications that were undreamt of back in teh sixties. Now it makes sense to have a modern bike, know nothing about it, take out breakdown insurance. and carry a mobile phone and just ride and not worry about it. You might have to pay a lot in case of breakdown, but that is it, that is that package.