This has been discussed before I think but there was a good article in
Road Racing World (sept. 2019 ) Excellent magazine for people interested in racing.
I always drained my oil hot but will change to draining it cold.
Short of the story : Drain Hot 4.5 % oil left
Drain Warm 6.8 % oil left
Drain cold 0.3 % oil left
^^ +1, hot drain here as well, and let it drip for some time....
Draining oil when cold is counter-intuitive ( hot oil is more viscous and 'runny' ) but I could understand that, when cold, the oil will cling better to itself, with gravity pulling it out better as a whole.
Also, workshops are under time pressures and the bulk of the oil will drain quicker presumably, than waiting... and waiting... and waiting for cold oil
The reason for draining oil cold is that all the oil is in the sump and all the contaminants will be in that oil. If still hot some of the "baddies" will still be in the engine. I always drained it hot ( including burns ! ) but from now I will drain it cold to see if more old oil will drain out.
(09-12-2019, 03:29 AM)Bazbro_imp Wrote: [ -> ]Draining oil when cold is counter-intuitive ( hot oil is more viscous and 'runny' ) but I could understand that, when cold, the oil will cling better to itself, with gravity pulling it out better as a whole.
Also, workshops are under time pressures and the bulk of the oil will drain quicker presumably, than waiting... and waiting... and waiting for cold oil
Some of the better shops put the bike in a cooler for a while to get the oil cold.....
I drain it hot and let it drip over night. Then it's cold in the morning.
Interesting numbers. Warm is the worst option?
(09-12-2019, 07:28 AM)Cormanus_imp Wrote: [ -> ]Interesting numbers. Warm is the worst option?
Yes, warm was the worst , it was a well done test with great accuracy.
The difference between the hot and cold percentages is enough for me to consider doing it cold from now on.