Why does Harley recommends Synthetic Oil for Eng and Trans right way, and BMW does no

Discussion in 'Parallel Universe' started by moulin6801, Apr 10, 2012.

  1. ragtoplvr

    ragtoplvr Long timer

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    US laws apply only in USA.. For example, Grp III can NOT be labeled synthetic in Germany. (unless there are recent changes)
    #21
  2. JoelWisman

    JoelWisman Long timer

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    That judge issued his opinion that synthetic should be a "standards based" definition, not a specification of how it is made.

    Once this determination was made, he left the door open for now and all time for the other side to prove that PAO performs better in any way, shape, or form, which they never could.

    The case was similar to slow old companies that built a product for construction. They always litigated that a fire wall could only be built by using their masonry brick 3 layers deep with an inch between.

    New companies came along with products that could resist fire for the same 3 hours but be 1/4 the thickness and a tenth of the weight.

    The old companies sued wanting the judge to say that a fire wall had to be built a precise way and that regardless of performance, nothing else would meet the fire code.

    In other words, old tech wants construction or manufacturing specification laws and definitions for products. New tech companies want performance standards so they can innovate new and cheaper ways to make things.
    #22
  3. MotoRandy123

    MotoRandy123 Been here awhile

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    To answer the original question. To "break in" means wear is happening. The Harley's tolerances are rather loose to begin with as it's air cooled and so parts grow a lot when warm. Using synthetic will slow wear so is a good idea to start ASAP on the Harley. The BMW has tighter tolerances to begin with so we want to wait for it to loosen up before we slow the wear. My question is why was there a service bulletin on the early single cylinder F650's that recommended to never use synthetic?

    You can use synthetic to essentially stop the wear so why not put it in from the get go and have a "new" bike for as long as possible?
    #23
  4. Pete7874

    Pete7874 Been here awhile

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    FYI, as of 2013, the mineral recommendation is no longer in the US owner's manual. They also don't mention Castrol either, and no mention of waiting until 6000 miles to start using synthetic like in years past.
    #24
  5. pilesofmiles

    pilesofmiles Long timer

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    Exactly.....and this is what was used at my 600 mile service this month. My service tech calls it a semi-synthetic blend 15w50.
    #25
  6. moe.ron

    moe.ron Pig. Can. Fly.

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    They put 10W40 in at the dealer?
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  7. leafman60

    leafman60 Long timer

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    1. Synthetic oil handles heat better than mineral oil. Not only does the oil withstand heat better but synthetic oil tends to make the engine run cooler.

    2, Water-cooled bikes get hot too, especially off-road types ! If you do a lot of low-speed trail and dirt running, you know it. That fan keeps running and you can feel the heat pouring out. I use synthetic oil in my BMW single for its heat capabilities.

    3. Non-water-cooled bikes like the HD are not necessarily put together with looser tolerances. In fact, often a water-cooled bike has looser tolerances. For example, as it warms up, the piston conducts a lot of heat. It takes longer for that heat to warm up the water jackets and the mass of the surrounding cylinder to reach equilibrium than warming up a simple finned cylinder of an air-cooled engine. Since the water-cooled piston gets hotter relative to the cylinder quicker than an air-cooled engine, the piston expands more relative to the cylinder than with an air-cooled engine. Hence, greater clearance is necessary.

    4. Many engines nowadays come from the factory with synthetic oil in them. Materials and fitment these days don't require as much "breaking-in" as in the past. Maybe the Harley is just a little bit more advanced in this aspect than the BMW.

    5. If you use synthetic oil in a wet clutch power-train be sure it has the JASO rating on the container. That means the oil doesn't have the type of friction modifiers that will pollute your clutch plates and make them slip. Shell Rotella, both mineral and synthetic, is JASO. Same true for Mobil 1 Motorcycle oil.

    6. As already mentioned, zinc/phos content is beneficial for motorcycle engines. Mobil 1 Motorcycle Oil is very high in zinc, ZDDP. I use 20/50 M1 in H-Ds and BMW twins. I am using M1 10/40 in my BMW single but Rotella is good too.

    7. Do not use synthetic in vintage bike engines. You will get weeps pass the seals.

    8. Many European manufacturers are going to the 10-60 synthetics. I think a 20-50 would be fine but 10-60 is coming on now. You can buy it at a good price at NAPA auto parts stores under the German "Liqui Moly" brand (but it does not contain moly).
    #27
  8. ktownbobski

    ktownbobski Been here awhile

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    +100
    #28
  9. ktownbobski

    ktownbobski Been here awhile

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    +100 . . . thought the 'motorcycle oil' was implied in the other post!
    #29
  10. pilesofmiles

    pilesofmiles Long timer

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    Nope, I miss typed and corrected my post-15W50 synthetic blend.

    Cheers!
    #30