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1985 xj700 what size carb jetting for AirPods help!!

Discussion in 'XJ Modifications' started by Terry duncan, May 28, 2023.

  1. Terry duncan

    Terry duncan New Member

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    Hey friends,
    I recently removed my airbox. After reading all the posts about not removing the airbox lol but it’s some thing I really wanted to do. I replaced it with AirPods now I am regretting the carbs. Does anyone know what size the Jets should be? And any other helpful tips thanks so much. :)
     
  2. Dallaswb

    Dallaswb New Member

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    The problem with airpods is there's too much air. just stuff some foam in them and you won't have to reject,restrict the air flow the best you can. And maybe turn up the pilot screw.
     
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  3. Terry duncan

    Terry duncan New Member

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    I did do that and it’s idling pretty well now but now when I go to second gear the engine cuts out. Any ideas?
     
  4. Dallaswb

    Dallaswb New Member

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    Did you set your idle at 12 Grand,use soap and water to check for vacuum leaks around your crab boots and petcock vacuum line.im not sure what that is, but that doesn't seem like an air filter problem.
     
  5. Bryce W

    Bryce W Member

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    Back when I was trying what you are, my bike was running super rich and would die when I went to switch gears. Check the plugs. If they are super black, you introduced too much restriction, if they are white, you need more restriction, if they are clean and tan looking, they are good. If you are wanting to use pods, get used to checking the plugs.
     
  6. Minimutly

    Minimutly Well-Known Member

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    This restricting airflow is silly. You need to look at different springs, needles and likely jets...
     
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  7. Terry duncan

    Terry duncan New Member

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    Does anybody know the original jet size. (The size of the hole, drill bit wise? I drilled my jets too big and wanted to go back to the original size. Please help :)
     
  8. JPaganel

    JPaganel Well-Known Member

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  9. Bryce W

    Bryce W Member

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    If I remember correctly from a post long ago, Yamaha would put the jets under some amount of water and force the water through the jet. After a given amount of time, the amount of water that went through the jet, and therefore how much the jet "flowed" would determine the jet size. A larger jet allowed more water to pass through, meaning it got a higher number. The difference in hole diameter size between a #42 and #40 I feel like you would not be able to do via a drill bit, unless you were a machinist and could measure thousands of an inch, I mean after all, these holes are small!
     
  10. Bryce W

    Bryce W Member

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    With that being said, places like Amazon or ebay do sell rejetting kits, though I dont know how accurate those are. You can get them through Chacal, the vendor on our site. To completely rejet a bike through Chacal is like 60 bucks, but those ebay kits are only 20, so....
     
  11. Terry duncan

    Terry duncan New Member

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  12. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Is this the air-cooled or water-cooled XJ700 model?

    Also, if you’ve ever wondered what the numbers on your jets refer to:

    - on Hitachi fuel jets, the numbers refer to the actual physical size of the passage hole expressed in millimeters, i.e. a #114 fuel jet is 1.14mm in diameter, a #42 fuel jet is 0.42mm in diameter, etc. Hitachi air jets are a whole different animal, measuring airflow volume at some (unknown) specific level of vacuum, and thus there is no direct (easily computed) relationship between the air jet passage diameter and the Hitachi "size" on their air jets.

    - on Mikuni fuel jets, the numbers are a measurement of the volume (cc’s of gasoline) that will flow thru the jet when poured in from a height of 50cm. There is no direct (easily computed) relationship between the jet passage diameter and the Mikuni "size" on their fuel jets. And we do not know what Mikuni air jet numbers refer to…….although we suspect, as with Hitachi air jets, that it's a volume of air that can pass through the jet at some level of vacuum. Anyone who has insight into this issue please let us know more!
     
  13. Vladimir Kalinov

    Vladimir Kalinov New Member

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    Hi, just installed pods on my 1985 XJ700. My original pilot jet was 35 and main jet 105. I upgraded main jets to 110. Pilot jets I wanted to upgrade to 37.5 but I ordered wrong shape pilot jet and it didn't fit. I turned left/unscrewed what I think was the mixture screws 1.5 turns to compensate not having bigger pilot jets. But two of my four mixture screws had very little thread left so I don't know, I think I turned them 1 turn out.
    I thought the bike would be lean up to half throttle but when I started it it was fine, started just like it did with the airbox.
    On the road I noticed a significant change. The engine had more grunt in low/mid revs. Made a great sucking sound from this airpods too. Whereas with the airbox my midrange was really awful now it is acceptable. Gone is the sharp power gain at 7,500 RPM, there is a much smoother transition now. But it almost feels like I lost some top end which does not make sense to me. Must be that the smoother power transition is masking the true power at high RPM.
    I am definitely happy with the result so far. If I get my hands on four 37.5 pilot jets I will go for them.
    I would also get a thinner needle to further improve throttle response at half throttle but I can't find just needles, only full jet kits. Also, I was hoping I can adjust the needle clip but mine seems to be non-adjustable?
     
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  14. Timbox

    Timbox Well-Known Member

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    Terry, please take the time to do some looking on this board. You can search for PODS and find some many people that have done the same thing. You will have some good results if you find tune them enough.

    The bike may look good with the PODS on it but the engineering of the carbs are for a air box is what helps the carbs work as they should from factory.

    Best of luck in your PODS conversion. I hope you take the time to look for other members that have had good luck and can give you the guidance you need on this.
     
  15. Vladimir Kalinov

    Vladimir Kalinov New Member

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    When I first saw the small airbox opening I was amazed. It looks like forcing a sprinter to breathe through a straw.
     

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