Yet another winter oil change question. I have two for the membership. 1) I have a 1996 HD Road King, run's like a train. It has had all oils changed in 2009. Engine oil is Amsoil 20-50, gearbox is Bell-Ray Syntheic and the Primary uses normal HD dino primary oil. I have since the fall of '09 till today put a total of 1240 km. This will be the second winter of not changing the oil. Should I go ahead and change knowing that this oil can go for another 8000km. The bike doesn't leak a drop and never had to top it up with new oil. The oil is very black, however doesn't smell like unburnt gas. 2) I also have a 1972 Triumph Tiger. This has had a total rebuild. I have already changed the oil at 500km, and now the oil in it has a total of 900km. All oil is normal dino Castrol 20-50, question is again should I change all the oil or let it sit. Thanks in advance.