Why the Oil Cooler?

[rob_imp]

Back in the day when almost all bikes were air cooled, the mechanics told me and some buds that for every 20 degrees you lowered your oil temp, you doubled your engine life. I assumed it was true because they more knowledgeable than me and most of them actually had an aftermarket one on their bikes. In fact, I had never doubted it and until now hadn't thought about it in many years.