WR250R.

Cons. : Cost (in UK)
Service Interval - 3000 mile for lube
Water Cooled.

Pros : Power
Light Weight
Powerful Generator

I have a TT250R

__________________
I wanna go back.

If buying in the UK, no question the little XT's and TTR 250's are the go. I've heard many positive reviews on these simple, tough and reliable bikes.

You can buy a new XT250 here in USA but they aren't all that cheap used.

The service interval for Oil change at 3K miles is about right ... and I'd follow that number for most dual sport singles. (including my DR650) With quality
synthetic oil you may push that interval in mild, slow riding.

One note on the WR250R is valve check interval. 26,000 miles.
Most find valves in spec at that time. But not as easy to do as on your TT, XT's or DR650!

Water cooled. As rider of DR650 (Oil/Air cooled) I can relate to this, love simplicity of air cooled.

So yes, Water Cooled can be a negative, but not so much if you add radiator guards. In all my reading up on WR I've come across very few busted Radiators due to crash damage ... but of course ... can happen.
You can also bust a hose, have a water pump fail. Rare, but could happen.

Power: Yes, for a stock 250, WR is not too bad, but there are many 250's that make more power. Most KTM or Husky put out more HP ... but not reliable going 30,000 miles without much care. And, of course all two strokes make more power too.

The good news on the WR is that it makes fair power but still returns good economy. (60 to 70 MPG, depending)

Weight:
The WR is lighter than my DR650 ... but it's not all that light compared to some other more race oriented bikes. In fact, I'm thinking your TTR may weigh less than the WR250R?? (not sure) Good news for me is that the WR "feels" lighter than my DR650 (in fact, WR is about 70 lbs. lighter than my DR650!) and I can actually lift it up easily!

Generator output is a big plus to me too. My DR only puts out 200 Watts total.

Comfort:
I'll add this in. For a stock bike, the WR is quite comfortable. Add a seat pad or Seat Concepts ... and you've got close to all day comfort. I was shocked how OK the stock seat felt.

But the real advantage (IMO) the WR250 has over many other 250's in the class is suspension and chassis design. For a stock 250 the suspension is not too bad and chassis really handles well.

The rear shock needs work but the forks only need a lighter oil and some careful adjustment. The shock is harsh ... needs a re-valve. But most ALL bikes need suspension work, so no surprise. WR Handles rough tracks better than many other bikes ... even larger, fancy $$$$ bikes. Tracks straight over ruts, goes where you point it. Very easy to ride off road, no stress.

Cost:
Even in USA/Canada the WR250R is quite expensive, either new or used.
But if you're in for the long haul, probably worth the price if you use the bike
as intended.

A bunch of my friends have gone to the WR 250s now, most of these guys are into their 60s and looking for something a little lighter.. I helped a friend set his up for Adventure by adding the bigger of the 2 IMS tanks which really extended the reach of the bike and I also helped him with luggage ideas..

I rode one up a very steep rocky climb for another friend who had tired himself out and the bike did ok, even for my 200+lbs.. The WRs that my group have picked up used here usually run between $4000-$5000 CAD and are low mileage examples... I could of picked up a good luggage equipped unit last year with low mileage for $4200.. Personally I am waiting for something in the 400CC range, if Yamaha puts out something similar in that size I would be all over it..

In B.C. it costs the same to insure a 400 as it does a 250 so it makes sense to go with the bigger displacement and have a less stressed engine for loaded up travel... A couple guys from Vancouver are touring some of the rough bits of the planet on a pair of the WRs and have done OK, though at times they were wishing for more poke... One of the bikes suffered a meltdown at around 30,000 KM and required a full engine rebuild, the other I believe is still on original engine parts.. All in all a good bike that could be a great bike with 30% more displacement..

Yea, it could use more poke for sure. And yes, better old guy bike! (I hope)
Yamaha fans been begging for a WR450R for years. So far, Yamaha has not responded.

I believe it's because they can't sell a 450 as easily in World Markets like they can the 250. USA/Canada too small a market to justify big investment.

There are thousands of posts on ADV Rider about WR250R engine upgrades, with several kits available up to about 330cc. (at least 3 different kits out there that I've read about) I've read at least 10 reports from guys who've done it.
Mostly all good feedback.

I've no idea how much better a 330cc kit would be ... and of course guys who did it rave about how much better it is. Natural bias?
it's hard to know just how much better it might be.

But to me, more important issue would be ... is the engine reliable with an over bore? Using a non stock piston/ring set? I seriously question critical NON Japanese internal engine parts. Seen a few failures on other bikes.

Fine for the Weekend warrior, but maybe not for the RTW traveler?
I'd need convincing to go the overbore kit route ... but it could happen I guess.

Will be interesting to see what bikes in this CC range come along. I'm betting Chinese OEM's have they're eye on things in this segment. But poor marketing and basically no one trusts Chinese bikes, no matter how cheap. Shame, cause I know a few are far better than a few years ago.

Our moto reality is changing fast. Who knows what is coming down the line.

Not so much a concern for me, I buy used ... so limited to established, proven ... and not too expensive bikes. WR250R has been around unchanged since '08 with a very solid reputation.

yeah, yamaha and honda suck big time recent years (suzuki, kawaski are not better) Currently I'm about to get to KTM 500 exc because nothing to choose from Japanese companies. As you said we asked for lighter ~500cc dual sport bike and we got nothing from ymaha. From honda we got even bigger, heaver Africa Twin

The KTM 500 is an amazing bike! A good friend has one and he is blown away every time he rides it. It is not the perfect travel bike ... but can be adapted if you are willing to put in the effort.

I rode it briefly ... loved it .. but the power was a bit overwhelming for this old,
retired dirt bike guy. Good news was the handling was stellar ... but I could never, ever use all that power.

Sadly, ALL the big four Japanese companies currently have excellent 450 MX bikes which all could be modified to great 450cc ADV Travel bikes.

Honda and Yamaha both did this with their CRF-L and WR250R bikes. Why not do the same with their 450's? Everyone has been asking this same question for years ... so far no response from any of the big 4.

If I could afford a KTM 500EXC, I'd buy one. We see used ones once in a while in the $8000 USD range (rare) new ones go for around $10K USD, plus lots of extra fees and taxes. Figure $12 USD on the road.

I'm looking at several used WR250's, under 2500 miles, less than 2 years old, in the $4500 to $5500 USD range.

Probably because the price range on those bikes would be very similar to the price range on the 600cc range bikes thus cannibalize sales. An Yamaha XT450 would probably cost almost the same as the XT660 if you count development and marketing costs for the newer bike, and most buyers would prefer the 660 over the 450 (a better "horsepower for the buck" since most of the regular buyers focus on horsepower over weight).