Wrong stack height?

Hi all,

Hi.

Have i bought a headset with the wrong stack height?

No.

The lock nut won't go on the stem any more than the picture below . . .

There is no stem in the picture.

and this leaves the filthy gap you can see, do i just need to get some spacers or should i cut my stem down?

Neither.

Firstly leave the stem out of this, it has done nothing wrong, you are just picking on it.

Your steerer tube is a little too long.