Simple title - f''king nightmare to achieve.
Well the buying was easy, the registration/insurance/plates etc was a total mind f*ck. But good news - there is a way.

My suggestions below: You may find cheaper, simpler, better alternatives that suit your specific needs. Be prepared for a TON of leg work, web searching, language translation, impossible catch 22 loops and/or thorough wallet cleansing.
Or....

1. Find your bike in Germany. Not the Netherlands, France, Spain, Switzerland etc. I chose to buy privately - know what I wanted, know bikes well

2. Negotiate with your seller an appropriate price. A good document is produced by the ADAC - Kaufvertrag für den privaten Verkauf eines gebrauchten Motorrades (contract for the private sale of a motorcycle)

3. Pay and take possession of the bike. The seller should give you a copy of your signed contractual agreement (which has vehicle details like VIN, TÜV expiry date - vehicle roadworthy inspection, milage, power, known defects), hand over title documents (Zulassungsbescheinigung Teil I & II), TÜV report and any other documentation like approval for any non-stock modifications like windscreen, tyre change from stock brand, power restriction.
This is where things may get a little tricky. The seller will most likely cancel and remove the current license plates at this point. Which makes things tricky to move the bike unless you have a trailer or van - until you get plates/insurance/title documents (Zulassungsbescheinigung Teil I & II) in your name.

4. Visit Cargo - a company specialising in documentation/export of vehicles in Germany and Holland. I found an office in Apeldoorn (Netherlands). Give them the following ORIGINAL documents (they will make a copy for you, until new documents in your name are obtained)
a) Zulassungsbescheinigung Teil I & II - the title documents in the seller's name.
b) TÜV report
c) Photocopy of your passport details (don't need to part from your important little booklet!)
d) An address where the vehicle will be registered to.

5. In 24-48 hours they will have the title documents in your name, liability (3rd party) insurance sorted, export plates valid for the required period printed, ready to put on your bike.

6. Ride (legally) into the sunset within Europe. Outside Europe you're going to need to purchase insurance at the borders.

The cost for me was €425 for plates, title documents, liability insurance for 30 days. This is all I want as I am heading for Africa and is plenty of time to get to an exit border. I initially thought that was expensive - but the issues with trying to do it yourself are almost impossible. After a month of trying to figure out the system, order of things, documents required, translating everything from Dutch and German to English (Google translation of important stuff sucks big time) - I was almost at the point of throwing in the towel and going home.

IF you want to have a go yourself, here are a few of the beautiful gems of German bureaucracy that you need to climb/bow to/give the finger/throw a tantrum at.

1. The local Fahrzeug-Zulasung authority requires the following documentation presented in Originale:
a). Zulassungsbescheinigung Teil II (Fahrzeugbrief)
b). Zulassungsbescheinigung Teil I (Fahrzeugschein)
c). Versicherungsbestätigungs-Nummer (eVB) zum Abruf (ausgestellt vom Versicherer)
d.) Hauptunter-suchungsbericht (wenn bereits eine HU durchgeführt wurde) empohlen; die Zulassungsbehörde behält sich vor, das Original in Zweifelsfällen zu fordern
e). bei zugelassen Fahrzeugen: geseigelte Kennzeichen-schilder
f). SEPA Lastschrift-mandat für den Einzug der KFZ-Steuer
g). Personalausweis zusätzlich bei Firmen aktueller Handels-registerauzug bzw. Gewerbeanmeldung. Pighten Personersonalausweis des zukünftigen Halters mit den aktuellen Meldedaten; bei Minderjähringen schriftliche Einwillgung der Erziehungsberechtigten und beide Personalausweise. Bei Firmen und Vereinen muss neben dem entsprechenden Registerauszug der Personalausweis und die Vollmacht einer im Register aufgeführten - zeichnungsbefugten - Person unterschreiben vorgelegt werden
h). Bei Erledigung durch Dritte: Vollacht und Personalausweis der bevollmächtingen Person
i). Bemerkungen

Easy eh? Sweet! Just translate all that - yeah no worries.
First parts - ownership documents in the previous owners name - easy.
Then an eVB number - a number that identifies your insurance policy. That requires ownership documents in YOUR name to purchase. And often proof of residency in Germany. But wait - I need an eVB to change the documents to my name, but I need documents in my name to get an eVB?? WTF??
Oh wait - it gets more fun. They want a vehicle inspection to ensure the physical vehicle VIN and details match their records. But how do you get the vehicle inspected? Bring it in! Yeah....with no plates on it? Van or trailer hire to get it there?
And then - a direct debit German bank account (which requires proof of residency to establish an account) to debit road taxes from.
Ok - think I need someone who is fluent in German to help me out here - oh, then you need an authority for them to act on my behalf.
Oh well - there's always their web site on-line help to make things easy: https://www.kreis-viersen.de/ (go on...have a play. See how YOU get on with it).
Ahh - several recommendation of Dooby and Lobagola here. Maybe he can help me out. Nope. Needs title documents in my name to provide insurance. Catch f*king 22.
Can't register or insure a vehicle in Netherlands, France, Spain etc without proof of residency. This German export plates seems to be the only avenue for a foreigner to buy a motorbike and get it on the road legally in Europe. There are lots more details about how long/can you extend the time etc but that is not the purpose of my post.

If you've got a simpler, cheaper, more straightforward process TELL US HERE!! Save a truckload of heartbreak, frustration and alcohol abuse.