Is there a maximum amount of y-axes that can be shown on a graph?

No, we support unlimited left, right, top, bottom X and YAxis.

However, each Axis is a templated ContentControl containing several canvases, a bitmap and a collection of labels, I would advise against creating too many as it will affect performance.

We have examples with 8 YAxis and they perform just fine: Quad Left Right YAxis sample

Hope this helps!

Best regards,
Andrew