At the beginning, the oil temperature of the engine rises relatively fast, and there is a time difference between the heat transfer of the oil and the engine casing. During this time difference, the oil cooler has already worked. At this time, if you touch the engine casing with your hand, you will feel very warm, and you feel good. It works. After the engine has been running for a long time, the speed of the vehicle has also increased, and the oil cooler has also reached the best working condition. At this time, the casing temperature of the engine has risen to a relatively high level. If you touch the engine casing quickly, you will find that it is very hot but not to the extent that you can't touch it. At the same time, the temperature of the oil cooler is also very high. This situation shows that the thermal process has been balanced. The air cooling and thermal conduction of the motorcycle's driving speed The process has equilibrated and will not increase the temperature anymore. At this time, the temperature is divided into two parts: 1. The temperature of the oil and 2. the temperature of the engine casing. The former is higher than the latter.
Without oil cooling installed, in the same process as above, you will find that the temperature of the engine rises very quickly at the beginning, and the engine casing is almost untouchable in a short time. After driving for a long time, the temperature of the engine casing is too hot to touch with your hands. Even if the contact is for a short period of time, the usual judgment method we use is to sprinkle some water on the engine casing and hear a squeaking sound, indicating that the temperature of the engine casing has exceeded 120 degrees.