Premix ratio for vintage bike

Discussion in '2 smokers' started by cdahl383, Aug 16, 2020.

  1. cdahl383

    cdahl383 Adventurer

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    I’ve got an old Suzuki PE that calls for 20:1 premix. Seems to run just fine on this (no ethanol fuel with yamalube 2R) .

    Heard from others it’s too much oil, oils are better now than in the 70s, etc. I should be running 32:1 or 40:1.

    What are you guys using on your old bikes and what seems to work best?

    2E26BD22-B9A9-456A-A8D9-CD189277392B.jpeg
    #1
  2. mikeysduck

    mikeysduck Slow Ride to Nowhere

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    Bikes were running 20:1... Racing bikes 16:1, back when. Be prepared to re-jet the bike to match the new ratio you choose.
    Good looking ride.
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  3. bobfab

    bobfab Long timer Supporter

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    I think another big consideration is the type of oil, #notanoildebate. There is a big difference between Yamaha type s and the silkolene I rub in my modern ktm e-xc! The oil bikes seem to want this really thin premix
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  4. Strong Bad

    Strong Bad Former World's Foremost Authority Supporter

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    I grew up racing little Hodakas and other little two strokes. In my first Hodaka, back in the late 60's, I ran regular old Pennzoil 30 weight motor oil at 20:1. Not a big deal and except for a bit of carbon build up. Of course back then there were no mufflers clog up, we ran straight "stingers". I was recently given a completely stock Hodaka Ace 90 in which I now run Yamalube at 40:1 no issues.
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  5. AlpinaE24

    AlpinaE24 Long timer

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    klotz r50 at 40:1 for everything
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  6. snarlyjohn

    snarlyjohn Human money repellant

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    Ask ten different people and you'll get ten different recommendations, often fervently supported. The truth is that unless you run something with an especially high specific output - in which case you'll be in castor territory - damn near any oil at any reasonable ratio will be fine.
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  7. cdahl383

    cdahl383 Adventurer

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    I’ve been running 32:1 with 91 no ethanol fuel and yamalube 2R. Stock jetting. Seems to run just fine like this.

    Here’s a pic of my plug (BR9ES). Looks pretty good so far.

    Attached Files:

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  8. 1wicked55

    1wicked55 Been here awhile Supporter

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    Ditto
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  9. KennyV

    KennyV Been here awhile

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    I been running Yamalube 2R @ 32:1 premix, 93 non ethanol my Yamaha DT250A with stock carburetor jetting for 15+ years. Runs great no issues.
    #9
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