This summary post on ADVRider from a West African trip might also be helpful: Wanted RTW on a KTM 1190 - Adventuring Into The Heart of Africa.

1190 is ostensibly the same bike as the 1090. If you take a 1090, get a centre stand for it.

The 690 is not a smooth motor, it is not far off the vibration level of the 640... Having ridden both back to back, there was not much difference between the 2.. That being said, the 690s larger power output is very apparent..

It is funny how there are the 2 different views on travel bikes, some guys feel they need 100+ horsepower and others are happy with 20... I prefer to go more to a midsize lighter bike and at the moment am waiting for someone to put out a 400cc bike so I can replace my aging 640..

I agree. I actually like both approaches, strangely enough!

My relationship with my 100+ hp bike is definitely not a practical one, and has very little to do with practicality of travel (perhaps it's marginally better for very long distances in a day in good conditions) but I just have so much fun with it and find it exciting to ride.

But make no mistake, that's certainly not a practical/functional benefit — if anything it's impractical and makes travelling more difficult, particularly in difficult terrain. For me, personally, part of the challenge is being able to build the level of skill to ride a big bike where others can only ride small ones.

Again, none of this is rational, it's emotional and probably quite heavily correlated with testosterone.

On the other side of the coin I totally see the benefit of lighter weight bikes with simpler mechanics that are not so performance oriented being practically speaking a great choice as a travel tool. If I was perhaps older, wiser, smarter I'd just buy a DRZ.

No question, 690 = power. I do disagree regards vibes. The 690 at least is less vibey within certain RPM ranges and latest version of this motor is said to be quite a bit smoother than earlier iterations. (2017)

The 640 vibes, in my experience, were BRUTAL. This view has been expressed widely by owners (mostly now X owners!), press reviews and so on. City Bike, San Francisco had several KTM 640 test bikes during my tenure there. I tested the '99 640 Dual Sport, '00 640 Adventure, '01 Duke 2 and 640 SM. We would get these bikes for 1 to 2 months each, so plenty of riding time by myself and staff.

I tested the Adv 640 in Nevada's Black Rock Desert. Bike was quite good in deep sand and rough rocks. Horrible on longer paved sections. (we were 80% off road on that ride) But, to contrast, I liked the Duke ll do much ... I bought one for myself! It had vibes, yes, but NOTHING like the 640 Dual Sport or ADV 640. By contrast, I felt the 690 was not smooth ... but smoother than 640.

True! But how can we ignore a bike like the KTM 500EXC? Granted, not the perfect travel bike in stock form, but seems to me that an ADV version could be created.

IMO, it's hard to beat your 640 in terms of HANDLING and LIGHT WEIGHT ...
and it's paid for! It's a great bike to ride off road, feels lighter than some 400's (XR400, DRZ400). Only thing missing is BULLET PROOF reliability. IIRC, it's lighter than the 690, power is not extraordinary, but adequate. You know the bike well and keep up with it's maintenance which means it could be RTW ready.

I'm going down the HP scale ... 250's. The WR250 is on my radar, will most likely become stable mate to my 62K mi. DR650. The DR will get a top end rebuild, the WR will become the new work horse.
My new (to me)'13 Ducati Hyperstrada is now my "street only" ride.

The 500 is a great bike, but the rear sub frame is too lightly built... What I really need is something 400CC or less to fit into a lower insurance rate category than my 640... The 640 would become my summer bike and the 400 would be for year round riding..

What makes any bike bullet proof reliable is the person that owns it... Whether it be a euro or a Japanese example the bike will not last if not maintained.. I have owned around 25 different bikes and only 4 have been euro bikes, the rest were Japanese and there is no magic, the Japanese had as many, if not more issues than the Euro bikes...

I would already own a DR 400 if they had come with a 6th gear, having a 5 speed box is a step backwards from the DR 350 days... I prefer the DR 400 to the 650 as in most respects it is a better bike, suspension, handling, lower weight and not far off in a power comparison, just give us a 6 speed gearbox when they go to fuel injection..

The 640 has been a good bike for me that has held it's novelty for a good many yrs, more so than for any other bike I've owned.. 640 parts production is starting to reach its end so the bikes days are numbered as far as an every day commuter... I will likely still own my original bike yrs from now, but it will likely be second fiddle to a much lighter smaller displacement Adventure bike...

Hope you can find something that will live up to your 640's ability.
I agree with part of your assessment regards DRZ vs. DR650. If you use the DRZ as a road bike, certainly a 6th gear is needed. Would not be my 1st choice if fair amount of road riding is on the menu'.

I've toured A LOT with guys riding DRZ400-S, me on my DR650. In our group we'd have a few DR's and a few DRZ's. DRZ was just about as fast ... up to about 80 MPH. But the DRZ is working hard above 65 mph. The DR650 is loafing at that speed.

Off road the DRZ has big advantage, more fun and safer when things get technical or you want to push the pace. The "E" model, even better. I owned the E ... not street legal in USA so it was my Desert/Sierra/Mexico bike.

But on a Baja trip the DR650 was the better bike (for me) because of long highway sections. Also, RODE my DR650 from San Fran to Baja, then did 1500 miles off road, then rode the DR back home. A true dual sport ADV bike. You could do that on the DRZ-S but not quite the same experience on fast highway riding.

You can push the DRZ off road ... but pushing off road ... I'd prefer your
KTM 640. The geometry is just better, IMO. More confidence in front end. Tracks better through tricky ruts, doesn't get bounced off line. But all of them are too tall for me.

Sure, with lots of work the DRZ can be better but your 640 is already there.
Parts in short supply? Perhaps buy full set for rebuild, sit on them till you need them. That should extend things a few more years at least.

The hard part is having a bike that is good enough on the road yet still competent off road. On my DR650 I have to avoid technical stuff and slow down the pace.

On a 250cc I'm more relaxed and actually make fewer mistakes ... and I can safely UP the pace on the 250 where I have to be careful on my DR650.

On fire roads or easy two track, hard to beat the DR650. It does well, but still won't carve the corners with confidence like your 640 can.

Most really depends on destinations, length of trips and pace you want to travel at ... and of course what floats your boat. Big difference choosing a bike for bumbling round BC as opposed to riding out to Ulan Batar and back.

For short, local rides off road, hard to beat KTM 500exc. Leaving Canada?
Whole 'nother consideration.

My favorite of the EXC series was when they produced the 400 engine based on the same cases as the 450 and 525.. I was hoping that when they went to this new generation enduro engine that they would offer a street legal 400 along with the 450 and 500, but the 350 killed that program.. I looked at buying a project titled 450/525 and converting it to a 400, but with them already being out of production for a while getting parts takes a bit of digging.. For me it is worth getting a sub 401cc bike as it would save me $300+ on insurance per year..

I do have 2- 640 Adventures already and a stockpile of parts, so if it gets bad enough I can rob from 1 to keep the other in business... My spare bike is one that I had shipped to me through the post office, I just had to piece it together.. Here is the story on that bike: New 640 Build from the Ground up | Adventure Rider

I agree completely!! Power is not important! you don´t use all the horsepower 99% of the time.

Weight, reliability, range and suspension are way more important.