Learn Dutch: Verstellen kun je zelfs dit oude zadel niet. - You cannot even adjust this old saddle.

This is an example of fronting. By putting the infinitive Verstellen in the first position, it gets strong contrastive focus. The speaker is emphasizing the specific action of adjusting, as if to say: As for adjusting it, you cannot even do that to this old saddle.

Because Verstellen is at the front, how does it affect the rest of the word order?

In Dutch main clauses, the conjugated verb must always be in the second position. Since Verstellen takes the first position, the modal verb kun takes the second position. This pushes the subject je after the verb, triggering inversion.

Why is it kun je instead of kunt je?

When the subject je or jij comes directly after the verb due to inversion, the verb drops its -t ending. This is a strict rule in Dutch, so je kunt becomes kun je.

Why is niet placed at the very end of the sentence?

The word niet generally comes after a specific direct object. Here, the direct object is zelfs dit oude zadel, which is very specific because it uses the demonstrative word dit. Therefore, niet is pushed all the way to the end of the sentence.