i traveled london to capetown on my r100gs, and yes it was a handfull at times, but it was never stressed out, always (sort of) kept going and never minded how much fuel/water/food/usless rubbish you carried. a big plus was it was dead easy to pick up being so low with sticky outy cylinders (my first rule of choosing a bike is u should be able to pick it up fully loaded) and im not a big person. i did another trip on a xt 600 tenere which used about 2/3 the amount of fuel, was more fun off road, struggled a bit on the windy hils and was a bugger to pick up, even though it was a lot lighter. i think ease of maintenance, how much you have to modify it to get it usefull and comfort are all the important bits. some people will always ride big bikes and some will allways ride little-uns. try a few, c what you like best.

p.s. once youre away from home youll probably not go quicker than 50mph anyway...

We did the same trip on the same bike. It was chosen because at the time it appeared to be the only bike suitable for this sort of trip 2 up. It was the ideal bike as 2 people carry more stuff the whole weight and manageability thing goes out of the window anyway - it's going to be heavy! Incidently, our cruising speed was 60mph but this was also the maximum speed we ever reached on the trip. the bike in everyday use now happilly cruises at 75 so I suppose you could say the engine was unnecessarily large and wasteful on fuel.

I'm a big chap so manhandling a big loaded bike has not really been an issue but I would never consider taking a 1200GS near a 3rd world country for a whole load of valid reasons, most of which relate to the junk that has been added to a modern GS (compared to the R100GS) that adds a lot of weight and complexity but contributes nothing to its ability as a overland bike.

At the other end of the scale (and not considering the pillion aspect which would rule out anything smaller than an F800GS for me), I think there is a bottom limit on practical size for a trans continental trip. By the time the bike is loaded with adequate fuel, camping kit, other luggage etc saving a few kilos by choosing a 125 is irrelevant. I would say the bottom limit is 400cc. I would consider doing a trans Africa on a DRZ 400 but I'd want to travel very light and I would gear the bike up to help improve mpg and perhaps reduce wear and tear on the engine.

I can fully appreciate the idea of travelling slower and seeing more but I find that on any extended trip there are less interesting parts that you just want to get past.

I have to disagree with you here as I am considering taking my newly purchased Honda XR125 to Central Asia next summer, I will be saving more than a few kilos by taking the same kit that I take on cycling tours plus a few spares, cables, plug and a couple of inner tubes. It cruises at 45-50 mph which is 4-5 times faster than I go on my bicycle that I had also considered taking.
Although I have not tested it on a long run yet the seat is as wide as the one on my R80GS so should be comfortable and the chances of me taking it have increased considerably as I have just checked the petrol consumption and it used 9 litres in 202 miles, that is just over 100 mpg, at that rate the 12 litre tank should take me over 250 miles.

I've always worked on the 'how little can I take with me' principle although it's more difficult when you're travelling with a passenger. That said I've met a few long distance cycle travellers and have always been impressed with how minimal their kit is. On a motorbike you can probably always get to the next town even in remote places so it's all to easy to go for the soft option and stay in a hotel/hostel but you can carry enough kit to make camping the easiest/cheapest and most comfortable option but on a bicycle you're options are lmited although often this can be part of the adventure.

Probably splitting hairs but cruising on a small bike is different to cruising on a larger bike in that at even 45mph you will have to work the gearbox every time you reach a small incline or headwind but this is only a matter of accepting the differences.

Are you intending to ride across Europe to Asia or are you shipping the bike in? If you are shipping it in I can definately see the advantages of a small bike.

Yes I plan to ride to Central Asia and possibly back via a different route although no definite plan as to return and possibly none until I get there. My thoughts so far are leave in April and head south to Greece, Turkey, Iran and Turkmenistan. It is from there I will make some decisions about route but hope to be in Mongolia by mid July when ramadan starts, after that again not sure.
I can still carry a full set of camping gear on my bicycle, a lightweight one man tent, thermarest, sleeping bag, stove etc. it is just everything has to be lighter, ie more expensive and less in the way of spare clothes, the dinner jacket has to stay at home along with the kitchen sink that the GS will carry.

l like to toodle along minor roads watching a more detailed world go by as much as the next person. But in areas such as northern Canada and Alaska there are many very long, boring and often cold and wet stretches of blacktop. Slow going on the aforementioned 250 would have been a little on the excruciating side for me during those parts of the trip. Crank the speed up to 110 to 115 kph and throw in some hills, however, and the fuel economics plunge.

I agree that a comfortable dual sport in the 400 cc range would be ideal. Personally, I did not find the DRZ comfortable.

Who is Larry and why is he depressed?

This is who Larry is http://www.worldwidewords.org/qa/qa-lar1.htm

and this is the English sense of humour falling flat on its face

My first big trip was on a 750 Cagiva Elefant. It was awesome, would fly along at great speed, handled the luggage well. Bit hard to pickup when it went down. Italian so broke down a lot. What a great trip!

My second bigish trip was on a Honda Dominator (delivering to 'Adastra', another HUBBer by the Turkish border). It cruised along easily didn't go wrong at all (until after I delivered it, then the engine blew). What a great trip!

Third time I took an old pizza delivery 125 cc step-through down to Morocco. Very fuel efficient, lightweight, crap suspension, handled terribly off road. What a great trip!

Right now I'm riding to Australia on a 45 year old bike I rebuilt myself. It looks great, sounds amazing, breaks down all the time and my arse hurts. Am having a great trip!!

Whatever you take, just have a great trip. On a small bike there will be times you want a bigger seat, more luggage space and a bigger tank etc. On a big bike there will be times you want it to be 100 lbs lighter. Maybe think about whether you want to be doing more road riding or off-road, but other than that just get something with two wheels and an engine. Or pedals, the 'two wheels' is the main bit!

That's an interesting point, it's something I like about my old R80 ST, it goes over so far but no further. But I will be buying a lighter bike for touring as my possible route has some poor roads and I find the BMW's 210 kg a lot without adding luggage.

A good 400 or 500cc road trail would be about right and bearing in the above tip about lifting flat sided bikes, I think a couple of BMW style crash bars so that it doesn't fall all the way over !