100:1 Mix

Discussion in 'Motorized Bicycle General Discussion' started by Retmachinist, Jul 24, 2009.

  1. jauguston

    jauguston New Member

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    muddy,

    Be prepared to have your engine run richer than it did with a fuel mixed with more oil. The oil amount effects the viscosity of the overall fuel mixture. Less oil means thinner fuel that will flow through a jet easier. I would suggest you get a 66 and a 68 main jet from Sick Bike Parts. They are not expensive and easy to change. 70 is the stock jet.

    Jim
     
  2. bairdco

    bairdco a guy who makes cool bikes

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    are you getting a percentage on every jet sold by SBP?;)

    i've never had to re-jet any of my stock carbs on any of the bikes i've built and run on Opti-2 (or any other oil, for that matter.)

    not saying someone else might have to, but i think the majority can be tuned without worrying about re-jetting.

    also, what might work in washington might not work in canada. just sayin'. with different elevations, humidity, etc, bikes will work different.

    just find what works best for you...
     
  3. mapbike

    mapbike Active Member

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    Here in Texas Warm to Hot dry climate I have had to solder and redrill all of my carb jets to get my engiens tuned properly all of mine are redrilled with a size #73 wire gauge drill bit and this is what it took to get my plugs the right color and to stop the constant 4 stroking and cutting out a bit on the hills at times.

    I also use Opti 2 and mix it 1.8 oz's of oil per gallon of fuel and my engines run great on it.

    The proccess of soldering up the jet and redrilling it is very simple, no need to buy new jets unless someone has no tools to do the job, in the beginning I didnt have any wire gauge bits either, all I had was down to a #69 bit which was way to big so for just a few bucks I ordered a small set so I could redrill my own jets.

    None of my engines would be running worth a flip if I hadn't rejetted them......

    Bairdco, I dont what you are doing different.........LOL

    After bumping the compression way up on one of my engine and also having a good free flowing exhaust. I still had a overly rich mixture, I moved the clip up on the metering rod and still it was too rich, it run good on hills 99% of the time but 4 stroked it's buut off on the flats and even on slight inclines, now it only 4 strokes a tad at the lower slower cruise speed RPM's and has much more power than it did before I resized the main jet.

    Peace
     
    #483 mapbike, Apr 29, 2011
    Last edited: Apr 29, 2011
  4. flybytaco

    flybytaco Metal Molding Madman

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    i still wont run 100:1 lol no thanks i run 100:1 oil at 50:1 just got another 30gal of sabre yesterday it will be gone by november
     
  5. bairdco

    bairdco a guy who makes cool bikes

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    map, i don't know what i'm doing different either. at the deathrace in arizona all the california guys were tweeking their bikes to work in the arizona climate, while i was pulling my supertrapp muffler off to run an open exhaust. which normally should make it run worse. my bike was lovin' it!

    and taco, you just don't know what you're missin'...:)
     
  6. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    I always have to go .64mm/.66mm/.68mm

    #73 wire gauge drill bit = .61mm
     
  7. mapbike

    mapbike Active Member

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    If it works for ya and you feel confident in the mix you use, thats all that matters in my book, I've had my engines apart after running the Opti 2 at 1.8 oz's per gal/fuel 70:1 and they are super oily inside but at the same time very clean with no sign of any residue build up.

    Just based on what I have seen in my engines the mix I run with the Opti is way more than enough lubrication and it is the finest quality lubrication also IMHO, I love the stuff personally and would never consider running anything else in any of my 2 strokes period........

    I'm sure the sabre is very good oil as well, I have heard good things about it, but never used it myself, if I did run it I wouldn't run 100:1 either, I would only run 100:1 with Opti 2 because I know for a fact it has proven it's ability to over protect an engine at that mixture ratio.

    I run the 70:1 because the only place I have around here to buy the Opti 2 is a hardware store that just carries the packets for either a 1 gal mix or a packet for a 2 1/2 gal mix, it cost me $1.79 to mix a gallon of fuel with Opti 2 and gas here is $3.69 gal so it cost me $5.48 per gallon to run my bikes.

    I always say that if it works for ya and you like the results you get with it, just do it that way, the extra lubrication don't hurt a thing.

    Peace

    dnut

    dance1

     
  8. mapbike

    mapbike Active Member

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    Yeah I have always worked my way to the #73 / .061mm jet size

    I clean my plug well, go on a 3-5 mile round trip and then after engine has cooled a bit I pull the plug and check the color to make sure it's not too lean of fuel/oil.

    I can normally tell just by the way it is running if I'm about where I need to be, if I get to much 4 stroking it is a good sign of a rich mixture and if I have room to move the needle clip up a notch I will do that before I resize the jet again, but if I end up with the clip in the very top groove and still have a rich condition, I will heat the jet with torch again to refill the jet and then I will move down in drill size one time and then repeat this entire proccess until I get a nice light chocolate brown plug reading and the 4 stroking is normally where it needs to be at this point, ( slight off & on under low load conditions and zero under power and up inclines) this is how I tune mine and they run smoothe and produce good responsive power at a twist of the throttle, just the way I like it...........Yea Haw.......! LOL!


    Would be nice to have a Tillitson Carb set up on one of these engines so it would be easy to adjust for each day by just a little tweaking of the air/fuel mixture.

    I'm not an expert on all the 2 stroke stuff so I have been unsure about whether or not a diaphram type carb like the Tillitson's will work on these open port 2 smokers without the puffing back that these engines do damaging the diaprams in the carb. I know weed wackers and chainsaws use the little Walbro & Zama carbs with no issues but not sure about the Tillitsons on a China Girl, if anyone knows in facts on this matter put-em out here cause I would like to know.....oooop's a little off topic here but the tuning stuff brought me around to this question I guess.....

    Peace



     
    #488 mapbike, Apr 29, 2011
    Last edited: Apr 29, 2011
  9. mapbike

    mapbike Active Member

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    Well, Baird

    It sounds to me like whatever it is you're doing....you're doing it right and it's working great for ya......and thats all that matters, I only fix things that are broke and leave stuff alone that isn't.

    I wish mine would have not needed the resizing of the jets but they all did, they would run like they were but not very good, just an almost constant rippling /splattering/studdering even up slight inclines, sounded like a 4 stroke running with the choke about half way on with about that much power too, this was the case with all 3 of my engines I'm running now.

    They are very easy to tune though so I dont mind a bit, in my opinion if someone hate tinkering with stuff like this then they have NO business owning one of these China Girl Engines because that will always be part of the total package and this is where a lot of the noob's get frustrated with them, they think they are "one size fits all/mount it and forget it" which is far from the case as the rest of us knuckle busters know.
    ---------------------------------------------------------------------------------------------------------------

    "while i was pulling my supertrapp muffler off to run an open exhaust. which normally should make it run worse. my bike was lovin' it!"

    Sounds to me like your engines were enjoying a leaner condition after you removed the supertrapp muffler, because what you did was allow that engine to flow more air through it faster and so you leaned it up a bit, just think if you would take that jet down a bit you could enjoy that extra power all the time.....
    ---------------------------------------------------------------------------------------------------------------

     
  10. Nougat

    Nougat New Member

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    I put an expansion pipe and hi-flow air cleaner on my 50 before switching to Opti-2 at roughly 80:1. (I only have a 2 gallon can, the packets I can get locally are to be mixed into 2.5 gallons, and I can get maybe 2.25 gallons in the can).

    Downjetted to 66, and it's perfect.
     
  11. mapbike

    mapbike Active Member

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    Here are some pics of my plug after running with the jet drilled with #73 bit, I could propably go down to a #74 and still not be dangerously lean, pics aren't focused perfectly but the color can be seen pretty good still.
     

    Attached Files:

  12. flybytaco

    flybytaco Metal Molding Madman

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  13. mapbike

    mapbike Active Member

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    Thanks flyby,

    Yeah, I cant run the 66-68 jets in mine for whatever reason or they all run way to rich, like I said I might get away with a tad smaller, but no need they run very good with what I'm using and to go any smaller on the jet will just increase engine temp and premature wear resulting from that.

    I have three different types of exhaust on each of the bikes and they all are jetted the same with the same results, maybe I just have some wacked out engines compared to some of the rest, or maybe the stock air filters I'm running are a tad more restrictive causing the draw on the jet to be increased.

    Who knows.....( Shrug ) all I know is my current jetting work good


    dnut


     
  14. muddybike

    muddybike New Member

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    Na thats alright , I will check my plug after switching over and if need be I will rejet. But one thing I do know getting anything shipped up here is anything but cheap so if i need to I will just solder and redrill the jet , but only after I find it necessary. If I end up buying a shift kit , maybe I will throw a few jets on !
    Nice plug tho ;)
     
  15. dmb

    dmb Active Member

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    looks good to me. how far is the carbon up on the thread's?
     
  16. yodar

    yodar New Member

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    Like the man said. It is oil, not rocket science. Changing dilutions midstream works fine !

    All of a sudden I notice the motor is more powerful and has more compression. After a few months of 100:1 AMSOIL Sabre my motor runs slower and quieter to give me the modest performance I seek.
     
  17. mapbike

    mapbike Active Member

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    No carbon on the threads, it's just discolored looking in the pics


     
  18. flybytaco

    flybytaco Metal Molding Madman

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  19. culvercityclassic

    culvercityclassic Well-Known Member

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    I made the change to Opti-2 with my latest replacement motor and could not be happier. I was getting so tired of the smell and how dirty the bike gets with the oil residue. Started this new motor out and ran it very hard from the start, it runs clean and fast. I have also said before…Bairdco has been running this oil and his bikes prove this is one of the best options for a mix. I am a believer NOW.
     
  20. flybytaco

    flybytaco Metal Molding Madman

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