[Ducati] 900SS oil capacity?

[Wright, Dirk]

Hello all, I changed the engine oil in my 2002 900SS the other day and I only got about 2.5 qts out. I added the same amount back in, and the oil level is up to the proper arrow in the sight glass. I ran the engine for a while and all seems fine. I'm confused because the owner's manual says 3.9 litres, which is about 4.1 quarts. The Haynes manual says about 3.5 litres. What am I missing? thanks.