I'm trying to figure out exactly where I'm at with the amount of oil my bike is consuming and if I should be concerned or not. Knowledgeable input appreciated. Up until recently I have been changing oil every 4-5000 kms with 15w50 Motul 5100 / Shell VSX4. I haven't needed to top up the oil level much between changes except after a track day. The bike didn't appear to be using much oil, engine and gearbox felt fine. About 4500kms ago (50,000kms on odo) I tried Delo 400 15w40 ( I couldn't find 15w50 ). I used a genuine Honda oil filter - $26 OUCH! The engine immediately felt a bit freer, the gear box felt good also. Almost 1000kms later I did the track day (oil level before was fine) and didn't think to check oil level for a couple of weeks later when I noticed it was low. I put nearly half a litre in at this point (52,000 on odo. With roughly 53,500 on the odo I again topped up the oil with another few hundred ml. I checked the oil last night (54,500) and the oil was at the mid to low level. Meanwhile the engine feels nice and smooth, no trouble starting. The gearbox is feeling better than ever - I barely need the clutch except to take off. In summary I've put in an extra litre of oil over the 4,500kms interval. It's a lighter weight than I usually use - 15w40 Vs 15w50. The bike doesn't leak any oil. Ideas, thoughts?