Another Oil Mixing Question

CCI

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Harley Evo, owner has Lucas 20w-50 synthetic for V-Twins in it now.

Is there any sound scientific reason why Mobil1 20w-50 for V-Twins should not be used for top-up until the next oil change?
 

CCI

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Thanks. I would never want to do anything bad to anybody's bike but I also don't want to go buy Lucas when I keep Mobil1 on the shelf.
 

CCI

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I'm not concerned with the properties of either oil, as long as there is enough ZDDP and the oil meets the recommended requirements for viscosity and service conditions, it is beyond doubt for me based upon the number of HD engines I have rebuilt that any modern oil is going to be OK. These engines are unbelievably tough and the only failures I have ever seen from inadequate lubrication are either not enough ZDDP, the wrong viscosity in a big way, or a broken oil pump drive gear key.

Maybe I should have been more specific in my question -- I have read many cautions here about potential unexpected results from mixing different brands with different additive packages.

I have had great results from the M1 V-Twin formulation, there is a reason why S&S recommends it. I have also read some pretty unflattering comments here about Lucas, and while I have no direct experience or knowledge of it, I do respect the educated and informed opinions of many of the folks who post here so I thought it couldn't hurt to ask.
 
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I agree with what you posted. And an important thing to remember is Harley's oil does not come with any approvals, but Harley's. There's no API rating on their oils, just what weight they say they are. They won't even recommend brands of motorcycle oil that have ratings.They do recommend Diesel then want you to back to their oil. So does that mean it's OK to use, or not?. Either way,every brand of oil out there has been used in Harley engines since they have been made. Having no oil is probably the only thing that will damage a Harley Engine.,,
 
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Please. Supply any proof with actual examples of damage that has been done. Hearsay doesn't count.,,
I think myself and others might be wondering who this is directed to?
I can't find anything in the thread who you can be replying too.
Unless you are replying to me and don't understand my post was an answer to the OP question which was =

"Is there any sound scientific reason why Mobil1 20w-50 for V-Twins should not be used for top-up until the next oil change?"
My answer = "No"
 
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The search whether Science has tackled the question of mixing oils...
yields a few bits of information to help guide your decision...

1)First and foremost there is more risk of NOT topping of your oil
level that there is of mixing...

2)We all mix because during oil change up to 6.8% is left behind to
contaminate the new oil... the more changes the more mixing...

3)Chemically speaking the mixing oils (50/50) is a crap shoot because
the risk of upsetting the balance of additives...

Blackstone Labs Scientists...
"Usually, at least several of these additives will be synergistic. That
is, they react mutually, in groups of two or more, to create an effect
that none of them could attain individually. Changing or adding to
this formula can upset the balance and negate the protective effect
the formula was meant to achieve, even if you are only adding more of
something that was already included in the initial package."
 
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Maybe I should have been more specific in my question -- I have read many cautions here about potential unexpected results from mixing different brands with different additive packages.
The truth is that if both oils have an API license then they have met the requirements of ASTM D6922 which guarantees the oils will be miscible and not cause harm. The only unexpected result is for the winter rating, there is no guarantee the mixture will meet the rating of either of the mixed oils. It also does not guarantee the mixture will meet any license, specification nor approval of the mixed oils either. But there will be no harm.
 
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Been using M1 in my '01 FLHR since new. No issues. 5k OCI's.
I remember back in the day the myth of the using synth. oils in a HD it would cause your roller bearings to ''skate'' so only use HD dino oils was the dealer advice. LOL That was until HD started selling synth. oils.
 
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