Always feel a proper idiot asking these questions but here goes... 2004 R300 with anti cav tank - wanted to changethe oil pre Brands track day next week. So ran the engine up to temperature, removed sump plug and filler drained oil, took filter off and more oil out (obviously), left it to drain for about 10 mins. New filter on filled with about 6.5 litres of oil, ran it up, oil pressure ok, level looks ok but hard to tell with engine running. Woke up in a cold sweat.......... should I have drained the cav tank or does it drain through to the sump? Have I now over filled with oil?? Checked the forum and some opinion is yes you do drain the cav tank but this seems to be on 1600SS, some opionion is no. Can somebody put my mind at rest either way please? embarrased thanks Rob