Changing carbs and installing a injector nozzle

Discussion in '2 smokers' started by Shocktower, Jan 20, 2012.

  1. Shocktower

    Shocktower Long timer

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    I got my sweet new flat slide carbs the other day, but they do not have a port for the oil injector nozzle, so I got brave and drille and installed them. I was very apprehinsive, about this so I really though about how to do it. So here is how I did it, I drilled a hole just big enough to press the nozzle in, and put some 2 part steel putty around it and pressed it in sealing the thing.
    I added the putty because there was not enough metal to support the stock nozzle, now it is rock solid :clap.

    Attached Files:

    #1
  2. King_Troll68

    King_Troll68 Adventurer

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    Have you tried this carb on the bike? Did it work?
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  3. buelless

    buelless Been here awhile

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    I would have teed it into the fuel line right before the fuel line attaches to the carb. It will mix with the gas better there, imo. Good luck and hope your new carb works out for you.
    #3
  4. JonnyCash

    JonnyCash turd polisher

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    It doesn't work like that, sir! Shocktower, I think that will work fine. Just keep an eye on it to see that the nipples stay tight in the carbs. I once had an oil nipple like that fall out while riding. I looked down and my boot was covered with oil, quite a bit! The nipple had fallen out. I stuck it back in, and everything was fine. I can't believe I didn't wreck the engine, but it didn't. I have since epoxied them in place to keep it from happening again. Someday I'd like to get flat slides. Have you gotten to ride this thing yet?
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  5. Shocktower

    Shocktower Long timer

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    I am still fittling with it, I have a few more things to do, I used JB stick ( it is Epoxy :evil ) to secure the Nozzles to the carbs, I am still aprehinsive about them falling off too.
    Yeah the inline through he gas lines sounds cool, but the old ones had it just like that, so why try something new.

    I should have it running next week, just finishing things up :clap
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  6. buelless

    buelless Been here awhile

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    Back in the 60s and 70s we use to add a little 2t oil to the fuel in the gas tank as backup since there was a chance of aerating the oil in the injector system from vibrations, rough terrain, etc... Anyway, best of luck with your bike.
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  7. Ever Onward

    Ever Onward Older,Wiser, Smarter

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    With the injector nozzle on the carb, downstream of the venturi, its able to respond instantly to demand needs.

    The Yamaha system is a combination of engine RPM and throttle position that determines the amount injected at any given moment.

    If you were to tie it into the fuel supply to the carb bowl, you would end up overall averageing the oil/fuel ratio in that bowls worth of fuel if you were useing a combination of low and slow and full throttle high RPM's.

    If, say, you were to idle along at a very low amount of throttle position for a while, you may end up with maybe 70 to 1 mix in the bowl. Then you suddenly nail it full throttle for a mile. You would be under full load at 70 to 1 till you got to the next bowl of fuel.

    Then if you went back to idleing, you may have 20 to one fuel to ride around on for some time.
    #7
  8. Shocktower

    Shocktower Long timer

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    :eek1 No bueno I will just stick with my set-up proven by Yamaha :wink:, now I just have better carbs :evil

    BTW thank you for all the input
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  9. buelless

    buelless Been here awhile

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    After a little more thought and some web search, probably the biggest issue would be the affect on air/fuel ratio due to the changing amounts of oil being injected for various throttle positions. The more oil in the fuel, the leaner the A/F ratio. just my 0.02

    oh yeah, make sure you use a good quality oil intended for oil injection systems, not pre-mix oil...
    #9
  10. Shocktower

    Shocktower Long timer

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    It is so little, and proven by Yamaha so why change it if it is no broken :D, But I am a little skeert to start this beast, I probably will, this weekend :eek1
    #10
  11. Ever Onward

    Ever Onward Older,Wiser, Smarter

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    Agreed, the yamaha system is just fine. As a matter of fact, we ran it as stock plus 100 to one premix in the gas tank as a little extra safety endurance racing RD's back in the day.......no problems with lube ever.

    Be sure to bleed all air outta the injection system and bleed the injector pump good, double check your oil pump cable setting too.

    I used to run a little oil in the gas as premix for the first quart of fuel too.......maybe 70 to one.


    Not a bad idea to use non synthetic oil at first for break in before switching over to synthetic later. :wink:
    #11