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Thread: Gas/Oil ratio for KX85?

  1. #1
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    Default Gas/Oil ratio for KX85?

    Just got 2001 KX85 and new to 2 stroke engine.
    What is the mix ratio?
    I got Clymer manual and it says 1:32. but the previous owner says 1:50 and friend of mine says 1:60.

    I am totally confuuusssssseeeeeeeed!!!!
    Please give me your 2 cents

  2. #2
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    1:60?!?!? Yikes!

    I use 1:32 for my KX100. It's had no issues so far.

  3. #3
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    I run 40-1 in my KX500SM I also use Fuchs premo 2 stroke oil (full synthetic)
    Phlat and I are gonna tear the top end off next week to re ring and gaskets etc..... I'll let you know what she looks like apart.......
    Brian # 30


    KTM 450 SMR

    "Everyday is a good day" Just some days are better than others

  4. #4
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    32:1 for that bike would work best. Rule of thumb: 32:1 up to 125cc 40:1 for 250 50:1 for anything bigger. The new KTMs are suggested to run 60:1 to be more EPA friendly.

  5. #5
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    Rule of thumb ??? my manual says 32-1...........
    You will need to explain why a bigger two stroke needs less lube ???
    Brian # 30


    KTM 450 SMR

    "Everyday is a good day" Just some days are better than others

  6. #6
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    it also depends on your riding,beginners not on the pipe alot less oil. expert rapped out all the time I'd use more, worst case of using too much oil fouled plug, too little & pop.
    Hey Brian 696 clear your private messages(make room).

  7. #7
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    Extreme example, sand riding I ran 28:1 in cr500&250, but in motocross you'd never get away with that without fouling a plug. motocross I ran 40:1, hope this helps.

  8. #8
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    Quote Originally Posted by K-9
    . motocross I ran 40:1, hope this helps.

    Agreed. I Always run 40:1 no matter what CC size the bike is.
    Living in a nudist colony takes all the fun out of Halloween.

  9. #9
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    Caution with the pre-mix !!!

    Higher concentration of oil can cause lean combustion condition in the cylinder.
    Why? Because the more oil you put in the mix, the less gasoline get's into the cylinder, which will cause the bike to run hotter than it should.

    The reason why a bigger bike can run a little lighter mix, is that a lot more mixed fuel (=more oil) is passed through.

    Somewhere on the web was a page from somebody that wrote the book on stuff like that. I'll add the link as soon as I find it.
    After "NO FEAR!!!!" usually comes "Oh Shit !!!"
    ==============================================
    Bikes in Germany:
    1989 DT80 - sold
    1984 XT600K - sold
    1993 CBR1000F - sold
    1994 610TE Enduro - sold
    1996 WR360 Enduro - in storage (my treasure)
    Bike in the US:
    1998 CR 500 street legal - motarded ... Just great!

  10. #10
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    Quote Originally Posted by TomCRMI
    Caution with the pre-mix !!!

    Higher concentration of oil can cause lean combustion condition in the cylinder.
    Why? Because the more oil you put in the mix, the less gasoline get's into the cylinder, which will cause the bike to run hotter than it should.

    The reason why a bigger bike can run a little lighter mix, is that a lot more mixed fuel (=more oil) is passed through.

    Somewhere on the web was a page from somebody that wrote the book on stuff like that. I'll add the link as soon as I find it.

    ok..... thank you..... thats what I thought.........
    Brian # 30


    KTM 450 SMR

    "Everyday is a good day" Just some days are better than others

  11. #11
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    Quote Originally Posted by K-9
    it also depends on your riding,beginners not on the pipe alot less oil. expert rapped out all the time I'd use more, worst case of using too much oil fouled plug, too little & pop.
    Hey Brian 696 clear your private messages(make room).
    I am free no saved messages.....have you not got my returned PM's........

    my plug is never fouled......but my wife says different
    Brian # 30


    KTM 450 SMR

    "Everyday is a good day" Just some days are better than others

  12. #12
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    Ahh found it on Eric Gorrs Page. Something about Fuel and also something about Carb Tuning.

    http://ericgorr.com/techarticles/Fuel_Basics.htm

    http://ericgorr.com/techarticles/carbtuning.html#m

    There is also some really good books about two stroke tuning from Roy Bacon.
    This guy's got his stuff down BIG TIME. I haven't found these two books in english though.
    After "NO FEAR!!!!" usually comes "Oh Shit !!!"
    ==============================================
    Bikes in Germany:
    1989 DT80 - sold
    1984 XT600K - sold
    1993 CBR1000F - sold
    1994 610TE Enduro - sold
    1996 WR360 Enduro - in storage (my treasure)
    Bike in the US:
    1998 CR 500 street legal - motarded ... Just great!

  13. #13
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    Used 32:1 my entire life and always used a good oil like Motul 800 and have never cook'ed a 2 stroke.. why try diffrent than what the manufacturers who actually built the bikes suggest?


    Also, why would a bigger cc bike use a leaner mix since smaller cc engines like pocketbikes, and weed wackers require a leaner mix of 50:1?

  14. #14
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    Quote Originally Posted by Eddie
    Used 32:1 my entire life and always used a good oil like Motul 800 and have never cook'ed a 2 stroke.. why try diffrent than what the manufacturers who actually built the bikes suggest?

    Also, why would a bigger cc bike use a leaner mix since smaller cc engines like pocketbikes, and weed wackers require a leaner mix of 50:1?
    That's what i was thinking too.
    Living in a nudist colony takes all the fun out of Halloween.

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