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

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

  1. lake_harley

    lake_harley Been here awhile

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    I have a F7 Kawasaki enduro, 1975 I think, that I'm considering using as a basis for a street-tracker style bike. Just to keep things as simple and un-cluttered as possible I'm thinking of deleting the oil injection and going to pre-mix. Probably ill-advised, but just for the sake of conversation I'll continue.

    I recently got another one of the three identical bikes I bought running, and to be on the safe side, started it with about 30:1 premix and the oil injection still hooked up, just in case the oil injection wasn't working. What smoke!!!! After I determined that the oil injection was working and switched it over to straight gas in the tank....much better. Now that it's running pretty well I'm moving over to project bike #2.

    So......based on the 1st bike, maybe 30:1 might be a bit rich, I'm thinking. The oil injection varies the ratio from 70:1 at idle, to much richer at full throttle, if I recall correctly from the manual. What ratio would it take for good engine (cylinder/piston/bearing) protection at sustained higher RPM, without it loading up on oil too badly at idle. I'm thinking a bit of throttle blipping might be necessary to keep it from fouling the plug at idle if it's "oily" enough for the top end RPM? What ratio are other of you pre-mixers using? This will be a street bike.

    Thanks, in advance!

    Lynn
    #1
  2. scottpoley

    scottpoley Been here awhile

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    That really depends on what type of oil you're using. "Standard" 2 stroke oil could be anywhere from 20:1 to 32:1, while your better racing oils frequently recommend 50:1 or higher. Usually the better the oil, the less smoky it will be.
    #2
  3. lake_harley

    lake_harley Been here awhile

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    Wow! Fast response! The 2 stroke oil I have is probably "cheap"...Wal-Mart I think...came with a bunch of boating stuff I ended up with years ago. So maybe 32:1 may be a good spot to start, just to use it up? I think I have about 1/2 Gal. of the stuff left. When it's gone I would gladly buy better oil for the long term.

    Lynn
    #3
  4. Airhead Wrangler

    Airhead Wrangler Long timer

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    Careful removing the oil injection. Some of the oil injection systems also give extra oil to vital engine parts aside from just mixing oil with the gas. Before you disconnect it, be absolutely sure of what it's doing.
    #4
  5. anotherguy

    anotherguy unsympathetic

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    Don't do it. The pumps are reliable and simple as they come.
    #5
  6. lake_harley

    lake_harley Been here awhile

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    I do indeed understand and respect your advice, and am not questioning the reliability of the system. I more just want to do away with the "side cover" sized oil reservoir.

    As far as lubricating engine parts, the intake injection point is only into the air/fuel intake stream. I checked the ports and diagrams in the manual (Kawasaki shop version) and there's no direct oil port(s) going into main bearings, etc., so I feel safe from that respect. I haven't completely decided to do away with the pump, tank and lines, but if I leave it I may come up with some smaller reservoir, just for appearance reasons (ie: give it a more stark, race-bike look).
    ,
    Other than ratio suggestions, what's a good quality, low-smoke, 2-stroke oil (Oh NO...another oil thread?:lol3)?

    Lynn
    #6
  7. anotherguy

    anotherguy unsympathetic

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    I run Bel-Ray H1R @32:1 in my YZ465. Before that I ran Golden Spectro @ 32:1. It's 32 years old and only a 2nd oversize piston.
    #7
  8. baloneyskin daddy

    baloneyskin daddy bikaholic

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    I just found a case of Pennsoil 2 stroke oil in a garage that has to be 30yrs old. I hate to throw it away as the cans are in perfect shape and I can't imagine there would be any issues with the oil as its already over a million yrs old .
    #8
  9. LotaBikes

    LotaBikes Adventurer

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    Have you thought about rigging up a less obtrusive oil tank? Are you able to weld a cap to the backbone of the frame and put a nipple at the lowest point to attach the oil feed hose to? You may have to get creative as far as a filling hole though. I did this once to eliminate the oil tank and moved the fuel tank back about an inch then fabricated a fill orifice at the very front of the backbone with a cap. Held about 2 quarts. Similar to the brit oil-in-frame set up.
    #9
  10. darmst6829

    darmst6829 Been here awhile

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    Hi Lynn,

    I like Suzuki and Yamaha oils. Cheap and no smoke. Your bike wont smoke after running it on the street for a bit.

    Dave
    #10
  11. bones_708

    bones_708 Been here awhile

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    You'll just have to see what works. The reason for the oil injection is because the bike needs different amounts at different revs. How you ride has as much or more to do with the mix as anything else.
    #11
  12. concours

    concours WFO for 44 years

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    This is the correct answer.
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  13. buls4evr

    buls4evr No Marks....

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    Like Concours says.....Leave the pump on it would be my advice. They work very well and do not waste oil. Straight gas in tank is a real benefit on a street machine.
    #13
  14. concours

    concours WFO for 44 years

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    ...and for the love of goodness, use modern, synthetic low-smoke oil and enjoy better engine protection, less/no plug fouling, etc. http://www.amsoil.com/storefront/tdr.aspx is an example. Bel-Ray, Spectro, etc. are all good choices. Tens of thousands of miles on snowmobiles using the synthetic goodness. NEVER go back to the old shite. Use the old TCW oil to undercoat your truck:lol3
    #14
  15. rufus

    rufus We're burning daylight...

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    If you do mix it yourself don't forget that you are dealing with 2 different mix ratios.

    1. Gasoline to air mixture.

    2. Fuel mixture = gasoline +oil.


    When you richen the fuel mixture......(more oil in the fuel), this leans out the gas to AIR mixture. The Oil displaces the gas.


    Less oil in the FUEL mix, richens the fuel to air mix.


    Lots of people confuse these. Having too much oil in the fuel mix CAN cause your bike to run hot and seize.
    #15
  16. petefromberkeley

    petefromberkeley -

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    Thanks Rufus- I never thought about that. I'm not much of a two stroke guy but I am going to fire up an oldie soon.
    #16
  17. Forde

    Forde Been here awhile

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    it is a major ballache to have to try and mix fuel at the gas station, but if you arent going far you can do it at home and just never use more than a tank when you're out

    youll need to upjet if you are running premix.
    #17
  18. Shocktower

    Shocktower Long timer

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    I am restoring a 1979 RD 400, and may of people eliminate the pump, I will not for several reasons 1 mixing on the road sucks, and the injection system is proven, it was tough for me because I changed carbs without injector ports so I just mounted some, I will stick with this, because it is not broken so I no fixty :evil
    #18
  19. Bud Tugly

    Bud Tugly Gnarly old curmudgeon

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    Another vote here for keeping the injector system instead of running premix. If the current oil tank is too big and obtrusive for the look you want, why not just rig up a smaller one you can tuck away under the seat or something?

    In my experience bikes with the injector system run cleaner and foul plugs less often.
    #19
  20. fastdadio

    fastdadio Still gettin faster

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    Looks like we're voting here.
    +1 for the "keep the injector pump" party. Having owned several pre-mix and injected bikes, I have learned that the oil injector is my friend. Especially on the road. Don't do it.
    #20