I realize anything you read on here needs to be taken with a grain of salt and the bull sh.. can get very deep but August Hot Bike had a article on Performance Oiling. They stated Synthetic oil will make a Harley run 15-25 degrees cooler. Now boys, Hot Bike is the bible (note little b) But to me that's like saying bottle water is wetter then the water out of the tap. WHAT DO YOU THINK? No bull.. what we need is a real engineer's view. How bout you DR, Masters and Professors -- no Shus or Dickies allowed..... I want it to be perfectly clear. Do not want just another shady oil thread here.

 

I'll go on the side of caution and say that it does'nt matter. Hot is still hot and a few degrees difference won,t make a big change in performance.

 

I say no to Temp difference, although use Synthetic because of Less chance of oil breakdown at higher temps .

 

On the temp gauge in my oil bag, my bike runs 15° to 20° cooler on the hottest days (100°+) with Mobile 1..........

 

I've done countless hours of research on oil. Synthetic oil is free of any impurities so it can dissipate heat better. Now does that translate to cooler engine temp,perhaps. Some guys notice cooler oil temps,some don't.
My 106 doesn't run any cooler no matter what oil I use. I use the infra-red heat gun pointed at the heads,crankcase and there was no difference.
Your results may vary.

 

It's a myth. Synthetic can stand higher temperatures before it breaks down compared with conventional oil. That is not the same as "it makes the engine run cooler".

 

http://www.nightrider.com/biketech/oilinfo0.htm

 

 

this is the correct answer!!!

 

oil in itself cannot control cooling, the amount of oil can, how the oil is cooled and controlled can, but oil in itself cannot control minimum engine temps by the type of oil used, while synthetic oils do produce less friction, that will not control temp, as the friction levels are small and do not relate in significant degrees of temp