Low oil level

[mrded_imp]

I bought my CB1100RS '18 with 2000 miles on the clock.
When I got it, it believed to be fully serviced.

Since I bought it, within half a year I noticed the oil level was below the limit. To be honest I wasn't checking it very often, as the bike was relatively new, and I didn't expect to have any problems with oil.

I've checked the bike and parking, no visible marks of oil, so I don't think it was leaking.

I poured half a litter of new oil to get the level back to the mid-limit.

After running the bike for 10 mins, I also noticed the oil colour changed to black.

So I have a few questions:
- How come I lost so much oil after just half a year, and 2k miles?
- Is it normal on CB1100?
- Is the fact I got under the limit, may make any problems?

And in general, I want to know your thoughts regarding this. Thanks.

On the pictures you see:
- Low oil level as I noticed it.
- Ember oil, on cold bike after I poured half a litter.
- Black oil, on warmed bike after 10 mins. (the level somehow got up)