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Marvin
Lv 7
Marvin asked in Cars & TransportationMotorcycles · 2 weeks ago

10W40 or 20W50?

Summer is upon us.  I just put 20W50 in my air cooled 125cc engine.  I recently purchased a new bike with a 500cc air cooled engine. After break-in. use 20W50 for the summer. or just stick with 10W40 year round.

Some people feel that 50 is too thick for cooler running water cooled bike engines.

Update:

Of course I am using motorcycle oil that is recommended for wet clutches. Someone suggested that 50 might make the bike hard to start. It really does not get cold enough in SoCal for that to be an issue.

Update 2:

I use 20w50 year round in my jeep.  Why?  Because it sits parked most of the time, and when I do drive it, I am often going up hills to places like Tahoe or the Grand canyon.  When I drive across that horrible desert between LA and everyplace else it is damn hot.

Update 3:

The owners manual does not go into that detail.

5 Answers

Relevance
  • garry
    Lv 6
    1 week ago

    20/50 , more for old cars whose rings are worn , try 10/30 or 10/40 oil , multigrade for bikes , not car oil .

  • ?
    Lv 6
    2 weeks ago

    Hi , Marv. It was 96, here , a week ago.

    Depends. My Honda 650 actually ran cool. I still used 20W-50 either Rotella Or Mobil One.

     My Harley specs 20w-50 or 20W-60  for our 116 degree weather like Yuma or Phoenix.  

      What mfg: "recommended" may be way out of date with the quantum leaps  in oil chemistry. Best to ask a trusted 'wrench that Rides one  at an authorized dealer. Not All oils are the Same, some  Do work better than others. Harley Officially  discourages straight synth. because of the "roller  bearings" but this is not actually a concern. They just want you to buy "genuine" H/D oil.

  • a
    2 weeks ago

    I have always used 20W-50 in the summer.

    10W-40 is like water in a air cooled engine and you will burn oil

  • Robsteriark
    Lv 7
    2 weeks ago

    What “some people think” is irrelevant. All that matters is what the motorcycle manufacturer recommendeds.

  • Anonymous
    2 weeks ago

    Your owner's manual will tell you what oil to use according to the temperatures in your location.  It is not rocket science.  Do not overthink it.

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