Hi Brainstorm
The oil level window on my xvs650 is just under the sidestand I thing it should be the same for your xvs125!
It is hard to check it by yourself, what i do is I put a peace wood under the sidestand to keep the bike lavel! and put the bike near a wall so it can't fall the other way! hope this helps! Sorry I can't help with chamber thing I dont have that on my bike!
All the Best
Nael