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Differences in motor oil types

Discussion in 'Moto Club' started by cysoto, Jun 3, 2007.

  1. cysoto

    cysoto Gone Shooting!

    Jan 21, 2004
    Denver, CO
    Why is it that manufacturers recommend using motor oil grades: SG or SL instead of a regular (and cheaper) SM? Does this have anything to do with the wet-clutch mechanism? <p> And also... What is the difference between all these types of motor oil? <p>-Thanks
  2. whogasak47

    whogasak47 JPFO-GOA

    Sep 1, 2005
    N E Louisiana

  3. HollowHead

    HollowHead Firm member

    May 16, 2005
    Where the buffalo roam
    My understanding is that the main differences are air cooling and whether or not the transmission shares the engine oil. Most water-cooled bikes where the clutch shares the oil with the motor shouldn't use automotive oil since the friction modifiers found in car oil make the clutch eventually slip. Air cooled bikes with separate trannys and clutches can't use automotive oil since the just don't have enough zinc to wick the heat. They can use friction modified oils with no problem. My marginally informed opinion is to stick with the mfgr's suggestion, but never, ever, ever use thier brand (yamalube, harley davidson genuine, etc) since that is pure marketing. HH
  4. fnfalman

    fnfalman Chicks Dig It

    Oct 23, 2000
    California & New Mexico, US
    HollowHead is dead on with his assessment.

    Don't necessarily use "brand" oil for the reason that "it's because they know about their vehicles". Yes, they do know about their vehicles. And yes, oil companies also know about their vehicles too. As long as you're using the grade and type the manufacturer suggests, you're good to go. "Brand" oil is simply regular oil made by some generic joint with a brand name on it.

    There is one bike that I know of uses car oil: BMW boxer twin. I'm sure there might be some older models from various manufacturers are the same way but as far as I can tell right now, the boxer twin is the only current motorcycle that uses plain jane dino bone car oil. Or you can buy the BMW oil for twice the cost.