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  1. #1
    Huntersthmsn74's Avatar
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    Mikuni Triple Carbs- Inherent Issues

    Hey guys, just wanted to remind everybody on the inherent issues with the carbs and how to go about resolving these issues.

    So this weekend I had the infamous bog return again. Checked all the easy possibilities first: fuel filter, fuel tank check valve etc etc. Then came back to the obvious conclusion: clogged internal fuel filter in carbs. So got home, pulled the carb rack off, and checked all the carbs. Culprit was the filter in carb #1. It is amazing how little debris can cause issues in these carbs. It was only about 40-50% clogged. I am wondering if there is any way to prevent this from happening again, or make it an easier fix? maybe a second and better inline fuel filter? Let me know what anyone has come up with. The debris in the carb filter was almost microscopic, which I am sure is almost impossible to keep out of the gas unless i use like a friggin coffee filter to filter it before i put it in the tank. BTW this was 14hrs after rebuilding the carbs previously.

    Anyways, while I have the carbs out I am going to fix my sticky throttle. I have already pulled the throttle plates and shafts out, and have slightly drilled out the bushings. I am going to sand them next. The screws holding the throttle plates were a PITA to get out, I didnt do enough research, and had I done it, I would have saved myself some grief, but anyways, it is what it is. The screws when installed by yamaha or mikuni or whoever, intentionally presses the back end of the screws so they do not come out. You can grind the back off and they will come out easier. So, anyways, 4 out of 5 came out but two of the heads broke off, so I am going to try and cut a slot in the remaining bit of screw and back them out. If that fails I will just drill and tap the holes and go that route. Here is a link that explained what I should have studied previously, in case anyone wants to do this mod also and be a bit more prepared.

    http://www.greenhulk.net/forums/showthread.php?t=68083


  2. #2
    Almost's Avatar
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    I'm super picky about my fuel. I only use top tier fuel and I filter my fuel when I fill my 5 gal cans. You can pick up a mr funnel and use that for both filling your cans and your ski. If you get one pick up a big one as they don't flow as fast as advertised, my only gripe. I also empty the last little bit of fuel out of my cans befor filling. This helps empty any foreign matter left in your cans and keeps them clean.


    http://www.mrfunnel.com/Mr._Funnel/Home.html

  3. #3
    GGG's Avatar
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    The filters clog with crap produced from ethanol reacting with the bare aluminum in the carbs. Only thing that's going to prevent that is premix or non ethanol fuel

  4. #4
    Huntersthmsn74's Avatar
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    i am running stricktly non ethanol fuel (from racetrac), and premix also btw

  5. #5
    GGG's Avatar
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    Then what's in the screens?

  6. #6
    Huntersthmsn74's Avatar
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    a hair, and just sand/dirt/debris, not the yellow ethanol salt stuff that i keep seeing posted. i am going to look into the mr funnel for sure tho

  7. #7
    Ha! I just had a hair in mine too. Freaking dogs!

  8. #8
    GGG's Avatar
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    Check the gas cap seal for leaks too. Those things go bad all the time

  9. #9
    butterbean_29512's Avatar
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    Instead of an oem filter, I use a purolator f20004. The OEM filter is a screen, and let's alot of trash through. The f20004 is a paper filter, and filters much better. I haven't had any particles in my bucket filters since switching to them.

  10. #10
    Huntersthmsn74's Avatar
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    sweet i will def check out the purolator. i was thinking a paper filter would do a much better job than the stock one.

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