Bike has valves I've never seen before

[Joe_W]

You are missing a small pieco of rubber tubing that should cover the hole in the valve. Most repair kits sold in Germany (used to? didn't buy one in ages) have one of those or even a valve. Those were the standard bike valves in Germany for quite a while. They are called Dunlop valves and use the same pump setting as French valves (Presta). Either: get replacement valve (you already know how to change them), the piece of rubber tube or a replacement tube. In order to pump it up you do not need to unscrew it, just pump. If you just go to a bike shop with the valve they might just give you one form the spare bin (or the little piece of tube that is missing). Many people in Germany understand English well enough to help you (I guess). Where are you in Germany (just curious)?