Since quite a few members here have provided me with invaluable information both through existing threads and PMs, I thought I'd give back with my recent experiences in the Caucasus / Central Asia. FWIW I'm travelling on an EU passport with a bike registered in the land of cows and chocolate Long winded border crossing info first then visa info for each country at the end.

- Turkey > Georgia. Crossed over at Batumi. The customs agent had a hard time understanding that despite the differences in flags on the number plates, my bike is in fact *not* Georgian (the plate starts "GE"...). Relatively quick / straightforward otherwise. Didn't get asked to purchase insurance. My "home" insurance coverage ends at Turkey, though my breakdown covers the Caucasus and oddly enough Kazakhstan.
The road from Batumi straight down across parallel to Turkey was pretty rough for about 50km. Since the snow was still melting (mid-May) there were quite a few streams / mud ponds to cross. Not particularly suggested riding unless you're on an adv tourer.

- Georgia > Armenia. Turns out that the woman who refused to understand that the bike wasn't Georgian hadn't registered me in properly. Cue 1 hour wait while the customs agents try to figure out how to check me out since they couldn't find the bike anywhere. On the bright side there were some cheerful guys behind me in the queue that had some instruments and decided to get everyone dancing to folk music! Armenia was relatively hassle-free (I got invited into the customs hut to get in from the cold and ended up entering all the bike details into their system myself!).
I didn't get asked to buy insurance at the border however *insurance is obligatory in Armenia* as some Russian bikers explained to me. I imagine I could have got it at the border but as I didn't know this I didn't get any until a few days later - most banks will do this for you or be able to point you to somewhere that can help. Cost approx $7 for a week $15 for two.
As a sidepoint, if you're a visa-junkie, if you fill in the "e-visa" online, you won't get anything affixed to your passport, just a stamp. If you purchase your visa at the border (3000AMD) you get a nice full-pager though.
Riding in Armenia is nice and the ability to camp anywhere is a plus. Saw a few wolves + snakes that made it more interesting There's plenty to see and the people are amazing.

- Armenia > Georgia. The customs agent couldn't find my bike in his system (his system was in Russian whereas the one I filled in on entry was in English. Go figure). He refused to let me try to find it and decided to just wave me through instead... Met some friendly Austrians on GSAs in the no man's land between borders. There's a huge duty-free shop there that has some interestingly priced alcohol / cigs if you're so inclined, however it's only for those *coming from* Georgia as I discovered. There's another one when you leave for...

- Georgia > Azerbaijan. Customs asks me how long I plan on being in Azerbaijan, I reply that I'm here for Eurovision (as it made the visa application simpler as they waived LOI requirements for Eurovision) and so before I even ask, the customs agent starts making calls to find out if they can waive the 72 hour rule for me. Very friendly. Cue 2 hours of boss-calling-boss. Eventually they all agree that it's impossible to extend the transit period for the bike and that I will have to "pay" 20 manats (=€20) when I leave and that I can stay as long as I like. I was a bit sceptical but decided to give it a try and otherwise make a whole fuss about how badly they were treating their Eurovision guests (they went to very great extents to make sure that people visiting for Eurovision got the best possible image of the country - I even managed to get a Police escort through Baku in order to make it to the show on time through the traffic!).

- Azerbaijan > Turkmenistan. On the Azeri side: this is where the 72 hour rule came to sting me in the rear end. Yes, the fine was only 20 manats, however this is only payable at the central customs office in town.. As it was past 6pm on a Friday when I got to the customs, this was obviously problematic, especially as nobody could give me a better description of where to pay than "it's near the American Consulate". So, I jump into a taxi and run around like a headless chicken (the taxi took me on, but had no idea where the American consulate was). We eventually find it at 6.40 and THANKFULLY there were still some people around. Obviously, being Azerbaijan this wasn't going to be easy: you get a slip that you then need to take to the bank next door in order to actually pay the fine. Since it was late, Friday, and the customs agent was nice, he agreed to look after paying the fine in and just printed me off a receipt. GPS coordinates for the central customs office: N40.38766, E49.84387. FYI: if you overstay your 72 hours, just go straight to this office on the day you intend on leaving and pay up before hitting the port.
On the Turkmen side: 2 hours of jumping through a series of ridiculous hoops. I counted 15 different desks to go to. Without a Russian speaker I can imagine this would be incredibly difficult. Among other things, you will need to mark out an itinerary, pay a per km fee based on this, buy insurance, pay for bike sterilisation (when this was done is still a mystery to me) etc.

- Turkmenistan > Uzbekistan: leaving Turkmenistan was fairly straightforward. That is, assuming you don't get lost whilst trying to find the border crossing! I crossed near Farap - remember to turn left after the small police hut otherwise you'll end up just riding into the desert... oops. Turkmen customs were pretty straightforward. Uzbek customs took a while as their computer systems had crashed but otherwise no issues.

- Uzbekistan > Kyrgyzstan: I've read many reports about needing registration slips - no idea whether mine were checked. Got to the border north of Uchkurgan in Uzbekistan. It's a pretty sorry excuse for a border control tbh. I was the only person to cross through in the 2 hour window that I was there. I didn't actually have to do anything - just handed them my passport and bike papers incl customs forms and waited.. and waited.. and waited. On the Kyrgyz side, woke up the border guard who was sleeping in the hut next door and got my passport stamp. Oddly enough no customs documents for the bike.

As I'm in Kyrgyzstan now and this is my final destination (I'm going fly back from Uzbekistan) that concludes the border crossings!

Visas:
- Georgia: stamp at border, free for many nationalities.

- Armenia: I did e-visa. Also possible at border for many nationalities. Visa at border gets a full-pager in the passport whereas e-visa just gets a stamp at the border.

- Azerbaijan: I applied back home. Used the Eurovision ticket in place of a letter of invitation. Got double entry (for the way back). Took 10 days, pretty straightforward.

- Turkmenistan: applied for a 5 day transit visa in Yerevan. After 10 days of hoping to be able to pick it up I got an email explaining that Turkmenistan wasn't allowing foreigners into the country for at least another week and that they *might* be able to issue a visa then. Because of this I ended up having to wait for a week in Baku which wasn't my preferred option. Eventually, I got a letter of invitation from the embassy in Yerevan that I was told I could convert into a visa either at the border or at any Turkmen embassy which is the safest option. Turns out it was the only option as the Azeris won't let you take the boat unless you have a Turkmen visa in your passport. The Turkmen embassy in Baku has moved and is now located near the Kazakh embassy. Coordinates: N40.39542, E49.82637.

- Uzbekistan: applied in Istanbul (needed to get before Turkmen as you need visas for country before and after in order to get transit visa). Pretty straightforward, $110. Normally you need to pay at the bank etc but the consul just let me give him cash. I think I was a sight for sore eyes having hit the town hard the night before Got a 15 day visa with a 1 month validity.

- Kyrgyzstan: applied in Istanbul. $80 normally (3 days), $160 express (same day - roughly half an hour). Very straightforward. One month date-specific. Turns out I probably could have got this along with Kazakh muliple entry.

- Kazakhstan: applied in Baku. The embassy is open on Tuesdays-Fridays in the mornings only for visa applications. Applied on the Tuesday and was told I could pick it up on Thursday. Wasn't ready. Wasn't ready on Friday either and I left that night... Will have to reapply for one from here (Bishkek). Apparently it's pretty straightforward.


If you have any questions or need any clarifications, feel free to ask / PM me!