2 stroke Considering Oil-injection to Pre-mix....Mix Ratio??O

Discussion in '2 smokers' started by lake_harley, Dec 21, 2011.

  1. scrambler73

    scrambler73 Been here awhile

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    WEIGHT... and the fact that MX bikes have their necks wrung most of the time= RACEBIKE

    A racebikes engine lives in a much narrower RPM range than a streetbike, so jetting for premix with a engine that mostly lives between 10 and 14k is optimum.

    On a streetbike who's engine live's between 2k and 12K depending.. With Premix, you will either be over-oiling when ridden mellow, or potentically even under-oiling if you are not running a rich enough oil mix (say 80 or 100 to 1).

    Most oil injection systems are "Variable Rate", delivering more oil as your throttle is opened and RPM's increase.

    And a 2 stroke street bike is ANYTHING BUT a lazy man's bike. You are always putzing with something....
    And funny, of the 50 or so 2 stroke street bikes Ive owned, I cant remember putzing with oil injection pumps other than initial set-up after building an engine? Maybe I (and millions of others) have just been lucky.
    #41
  2. peter650

    peter650 Been here awhile

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    I give up. We are just going to have to agree to disagree on Pre-mix vs Oil-injection
















    but pre-mix is better :D
    #42
  3. anotherguy

    anotherguy unsympathetic

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    I knew he didn't have any pics.
    #43
  4. gplracing

    gplracing Adventurer

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    Carbon build up in an engine will be a result of two things, 1, using mineral oils (like in the good old days lol) 2, to much oil at part throttle (pre-mix) and or incorrectly jetted.

    If your heating your head gasket to a cherry red then quenching in water you are hardening it again, your looking to "anneal" it to take the work hardening out that is coursed by the many heat cycles it has been put through.

    I would recommend you relieve the bridge at the boring stage.

    On a side note if your are looking to quench a none ferious material then water is a bit harsh, oil would be a much better medium.

    Glyn
    #44
  5. Shocktower

    Shocktower Long timer

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    But but, if it is not broken why try to fixt it :huh
    #45
  6. peter650

    peter650 Been here awhile

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    I don't have pics of the 750, that was about 17 years ago.
    I do relieve the bridge but i still think it's a good idea to drill 2 holes in your piston {takes 5 minutes to do}
    You have to pull your top end down anyway, to check your rings, so you might as well clean it while you got it apart.
    I use to use minereal oil at 20 to1 about 30 years ago, that would carbon up a motor fast. Synthetic oil at 32to1 up to about 40 to 1 {i jet and run all my bikes at 32 to 1, but 40 to 1 could be crisper could never bring myself to go past 40 to 1} will get you to your next ring check, without pulling the top end down to clean it.
    The simple truth of the matter is, a motor will run better on pre-mix thats why race bikes use pre-mix. Oil-injection lets lazy people ride 2 strokes {until they seize due to lack of maintenance, or faulty pump}. Which brings us back to the fact, that some people {lazy people} just shouldn't ride 2 strokes.
    #46
  7. anotherguy

    anotherguy unsympathetic

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    Shaddap.
    #47
  8. scrambler73

    scrambler73 Been here awhile

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    no kidding...
    I doubt the guy even owns a 2 stroke other than his weedwhip.
    #48
  9. biggurn

    biggurn Yes, it is BIG.

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    Interesting thing here, he provides no evidence to support pre mix over O.I... other than O.I. is for lazy people... Hmm, funny thing is I could make the reverse argument, pre-mix is for lazy people who do not want to go to the efforts to properly adjust and maintain the pump...
    #49
  10. peter650

    peter650 Been here awhile

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    I just worked out what the problem is. Your American that explains why you can't work out, how much oil to put in your tank.
    #50
  11. anotherguy

    anotherguy unsympathetic

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    That's the best you have to offer? Really now.................shaddap.
    #51
  12. Shocktower

    Shocktower Long timer

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    People these are opinions on what way to run a bike, not a pissing match, you say Potato we say Potatoe, in the end what is the best, it is from years of proven O.I work fine, but also P.M has worked too. So what ever floats you scooter then run it, lets just not be a bunch of whiney people who thinks/knows better than the other guy BRRRAAAAAAAAAAAAAAAP! :clap
    #52
  13. anotherguy

    anotherguy unsympathetic

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    I simply shared my experience until Peter (how appropriate) began slagging and name calling. He's made his point and can go now.
    #53
  14. peter650

    peter650 Been here awhile

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    What a load of sh*t
    #54
  15. Shocktower

    Shocktower Long timer

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    There you go again, leave it be :dhorse
    #55
  16. YamaGeek

    YamaGeek Ancient trailbike padwan

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    Suzuki is well known for using shielding on their cranks of their Posi-force injection stystem to keep the crank area injected oil, from getting diluted by the fuel air mixture. SAAB has been doing this with the Sport and Monte Carlo engines since the early sixties.

    It's a proven system and why he's racing a Water Buffalo with the oil injection system removed is beyond me. Water Bufflao's were known to have a very effective and efficient injection system.

    I'm calling troll
    #56
  17. fastdadio

    fastdadio Still gettin faster

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    I'm going to throw a wrench right in the works. How about both? I haven't always done this, but have just tried it lately. Lemme try to explain. Bike; 77 Yamaha DT400. Top end refresh. I found everything in good shape when I opened it up. Complete de-carbon, light cylinder hone, reassembled with original, first size piston, new rings and gaskets. Knowing I would be breaking in and riding this bike in the winter, I went one size larger on the pilot jet and raised the main jet needle one notch. So, I figured since it's running little richer, and I wanted to give it a couple easy heat cycles, I put a gallon of 70:1 pre-mix in the tank and ran it out. A little smokey at idle, but, once warmed up and blown out, seemed to be ok. Then it snowed. I needed to get the snow blower running. So, I poured last years 50:1 stale sludge into the tank and went out and burned that off. Again, seemed ok. My question to the collective is this. With the carb jetted richer for cold conditions, is it necessary, or at least a good idea to add the 70:1 to compensate. (the oil injection pump is operating at stock setting) Or am I just wasting oil and adding excess carbon to my now clean top end? Has anyone else ever done this? I have not pulled the plug yet for a look-see, but will report back when I do. Whadda U think?
    #57
  18. anotherguy

    anotherguy unsympathetic

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    It's not necessary but many do it. Worst thing that will happen is a fouled plug.
    #58
  19. Shocktower

    Shocktower Long timer

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    That there is a 2 stroke sin :lol3
    #59
  20. fastdadio

    fastdadio Still gettin faster

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    I finally got around to pulling the plug mentioned in post #57. It's dark, almost black, but dry with no hint of spooge. With stock jetting it was running a nice deep tan color. So, not too bad IMHO. Think I'll keep adding the extra oil for the cold weather months. Just for the feel good insurance I guess. On a side note, I,ve discovered another good reason to keep an old 2-smoker around, It makes a good waste oil burner.
    #60