How come no one runs this? The books says it is excellent and 20-50 is good so why not run 10-40. I put Royal Purple 10-40 in mine the last time, should I go back to 20-50 for some reason???

 

20W-50 maintains its viscosity better at higher temps.

 

Great thanks. So I guess in the summer 20-50 and if I ride into the winter a bit around here 10-40. I have 3500 miles on this oil and just bought some mobil 1 20-50 today figuring I was going to get a good reason to change so I came prepared!

 

Yes, you should go back.&nbsp\\; The viscosity of 20w-50 at operating temperature is higher than the viscosity of 10w-40 at operating temperature.&nbsp\\; The tolerances on the bearings, machined parts, etc are chosen with an oil grade in mind by the engineer.
&nbsp\\;

 

I run 20w 50 all year.
&nbsp\\;
David

 

Talked to the stealer when he serviced my bike and he said that 20-50 is best since these are air cooled bikes. He also said that after seeing a lot of bikes come in needing engine service that used other oils and were gummed up, he recommends the Harley oil personally.

 

The damn site is not letting us post...

 

Bull-Butter!!!

 

Basically, anyone know who bottles the Harley Oil?