10W-40 engine oil

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Jul 26, 2008 | 09:03 AM

sportncruise

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10W-40 engine oil

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???

Jul 26, 2008 | 10:03 AM

Sarge4life

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From: currently NC

RE: 10W-40 engine oil

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

Jul 26, 2008 | 11:49 AM

sportncruise

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RE: 10W-40 engine oil

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!

Jul 26, 2008 | 12:39 PM

ssls6

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From: South Park, CO

RE: 10W-40 engine oil

Quote:

ORIGINAL: sportncruise

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???

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\\;

Jul 28, 2008 | 05:52 PM

breaknbad

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RE: 10W-40 engine oil

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

Jul 28, 2008 | 08:51 PM

hispeed

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From: El Paso, Tx (temp)

RE: 10W-40 engine oil

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.