Re: Oil Oil Oil
No, oil does breakdown as well as get contaminated. An oil filter doesn't catch 100%. So what the oil filter cannot catch stays with the oil. In a motorcycle you also have a transmission. How long does synthetic fluids in a transmission last or oil in a axle? In an axle they last a longtime because they don't see the heat an engine does nor the contaminants. A transmission sees heat as well, but not the contaminants an engine will.
One of my cars, when it is time to change the trans fluid, the shifting starts to become notchy. This is with a synthetic manual transmission fluid. It gets changed around every 20k whereas the manufacturer says 30k.
A motorcycle puts a lot of strain on the oil as it needs to wear many hats. In cars you don't have the motor oil working in a clutch nor a transmission. Motorcycles also have a smaller cooling system than a car; which is why you see the temp gauge go up when stopped in a motorcycle and not so much in a car. So the oil in a motorcycle will see higher temps, used moe heavily as around 4l of oil covers the engine, clutch and transmission. In cars you see some gears like the oil pump and maybe the cams shaft, but in a motorcycle you have a chain and gears on the cam shafts plus the transmission.