Amsoil 20W-50 motorcycle oil.

 

Go to your local'bike night' and count the number of air cooled bikes with oil coolers.
I live near Daytona Beach......our cops use Road Kings with 96". No oil coolers.
I ride a 96" Ultra. Heat index was 104 degrees. I rode over to Boot Hill Saloon. Draw bridge was UP for a sail boat....I sat idling for about four minutes. Got to the Boot,
shut off engine and digital thermometer said 275 dgrees. No pings, no knocks, no back fires...I figure I will be OK.

chuck

 

I also had some concerns with my bikes internal temp. Living in Georgia the "Heat" is always on people's minds. I think Harley says normal operating temp should be between 190-230/250ish. I went ahead and got rid of the useless outside temp gauge and installed a oil temp gauge(2006 streetglide) and installed an oil cooler. Good thing to do for a piece of mind and good for the engine on a bunch of levels(including lowering the temp) royal purple makes synthetic oil that is suppose to drop the temp of the engine too. Maybe something to look into. Hope this helps.

 

It's a personal choice. I don't care what anyone says, I would rather see engine oil temps at 225*-235* rather than 275*-300*' has to be better for the motor. If it takes an oil cooler to do that, then an oil cooler wil be installed but that's just me. Don't go by what somebody else is doing, do what you think you need to do.