Why everybody thinks he is smarter than Moco? You are wrong, guys! You are not smarter, only I am!

 

Thank you for doing your own thing and trying something a little different . Some of these guys act like the difference between 40wt & 50wt & 60 wt is huge. If thay did a pour test from unmarked bottles most of them wouldn't be able to tell one from the other.

 

Using a heavy weight oil when warm really isn't an issue. It's what happens on a cold start.
Oil Filters are designed to "Bypass" if the pressure drop across the filter element exceeds a predetermined amount. When a Filter Bypasses the entire element is pushed away from the filter base plate against a spring that is between the Filter element and the opposite end of the can. Cut a filter open sometime and you can see this very easily. This is a Last Ditch design feature to prevent a seriously dirty filter from starving the engine for oil. It's the lessor of two evils: No Oil at all or dirty Oil . . . not a happy choice but . . .
If the oil filter is designed for a significantly lighter weight oil (High micron rating) than is being used, the filter will "Bypass" on a cold start just because the weight of the oil is so thick. When the Filter bypasses it not only allows the oil to bypass the filter element which if this was the only issue wouldn't be too big of a thing assuming the oil is pretty clean, but it also tends to scavenge a small amount of the accumulated debris that was trapped by the filter element . . . and this is NOT a good thing!

 

I run 60 wt in my twin cam every summer. Been doing it for many years now. I do warm it up a little more before leaving for work in the morning but thats it. Never a problem. It gets damn hot where i ride and I have had 20/50 turn to the consistency of water. And as far as the filter bypassing. When you can tell me when you know the filter goes to bypass I will start listening. I used to run a baisly bypass spring in my last bike with 50 psi oil pressure. I ran it that way for 75,000 miles. Again never a problem.

 

You live in Arizona.
60Wt should only be run in the hot part of the summer. Once the evenings get into the 50's you got to get that mollasses out of there.
I think EVO's run a little cooler anyway. Now twin cams, they love 60wt when it's over 80. I know this because I tried it. But I won't do it again because you got to drain it out before it's used up.

 

Guyz remember, the oil in the pan was just filtered. And after it runs for 5 minutes, the viscosity of the oil, no matter what the weight, is down to just a little above water. I wouldn't run straight 50 or 60 if the temp is below freezing. But other than that, it won't destroy your engine, like some who preach doom and gloom do.

Just my opinion, take it for what it's worth. Just a bit above zero. lmao

 

To my way of thinking, the only reason to use less than 60 wt., is so the starter will turn the engine over in 40 deg. or less temp. Some guys say it won't flow into tight spots on start up. I say it's already in there and won't run off like the thinner oil. Just my 2 cents.

 

Jim, I'm agreeing with you and RandyDowdy somewhat. I just think even at 50 degrees, starting get's rough and it seems to not run right until it gets hot.

 

You're talking about a different Bypass. The Bypass Spring you're talking about regulates the maximum oil pressure in the lubrication system and that Bypass is a part of the engine. The Oil Filter Bypass is a part of the Oil Filter. These two are completely different animals and are there for completely different reasons.

I repeat; a heavy weight oil used in an application with a very restrictive oil filter (like a low micron rated filter) WILL bypass on a cold start (and cold to an engine means it's been sitting for 6 hours without starting in any ambient temperature a human can live in). This will scavenge some debris from the filter element.

Just because you don't get a flat tire every time you roll over broken glass, doesn't mean broken glass won't cause a flat tire.

 

Here in the lower midwest temperatures of 100+ in the summer are all too common, and night time temperatures are usually 75+.

Many guys around here run SAE 60 during the hot summer months, and even Harley themselves recommend a straight 60 weight oil when the outside temperatures are 80 F or higher.

Many others just run 20W50.

Sometimes I change from the Mobil 1 15W50 I run most of the year and go with RedLine 20W60HD. RedLine is one of the better synthetic ester based Group 5 fluids, and the higher viscosity can't hurt anything when the temperatures are up in 3 digits.