Oil sight tube leak.

I've heard a few stories of these sight tubes not being too good, mine has just started to leak from the top, can't see any damage though, just a small gap.
My oil is slightly over the max mark to, not sure if that may be the cause.

Thoughts?

Replace it with RC fuel line, instead of the expensive stock, hard, non plyable part , for the same price as stock you can get enough to change it six times or more,,,,,,

Replace the tube with a better material. There are lots of threads on here about what to use. Basically, anything is better than the KTM material

Try model aeroplane fuel line.

Ha, Mad dog beat me to it!