I bought the bike with about 6k miles, completely stock.
Oil was supposedly recently changed. Oil was supposedly checked by mechanic who installed the Yosh pipes and Rottweiler.

Oil light came on today, oil is very low. I can see it in the chamber but barely.

What would cause this? Assume it was actually checked...

And, what type of oil do I need to add to fill it up?
No idea what was put in, likely whatever is recommended, but bike didn't come with a manual.

What is best oil for '07 SD 990?

Thanks!