Keihin needle seat-- how to remove?
  • mustangnut
    Posts: 20
    Joined: Sun Jan 28, 2018 11:04 am

    Keihin needle seat-- how to remove?

    by mustangnut » Fri Jun 08, 2018 5:44 am

    I have a PD24 carb sitting on my workshop bench to rebuild, and noticed that all the rebuild kits come with a new brass needle seat. The Honda needle kits purchased from the dealership appear to also come with one. How do you remove the old one? Got the rest of the carb pretty much torn down and scrubbed clean--- but that needle seat won't budge(?) Can someone advise?
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    JimDirt
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    Re: Keihin needle seat-- how to remove?

    by JimDirt » Fri Jun 08, 2018 12:30 pm

    Off the top of my head:
    If its the screw in type with a hex nut head then it should just unscrew (counter clockwise) , there should not be any "tricks" to get it out ......... If its the type held in by the retainer and a set screw , then it should come out once the retainer plate is removed and should just rock or twist out as nothing but a O-Ring is holding it , the new one will tell you how its held in , its either threaded or smooth with a lip and has a O-Ring , can you post a picture of the inside of the carb where the seat is , and the seat ??

    Are you using a wrench or a socket/ratchet ?? , is the handle short or long ?? , perhaps you are not putting enough force into it , it should not be tight enough to break it or the carb , if it is there is something wrong , perhaps someone previously used Loctite on it , if so a slight bit of heat directly on it should break the Loctite free (like a heat gun or hair dryer)

    You would also get a better response if this would have been posted in the Carburetor/Jetting part of the forum , from our resident carb expert (Leardriver)
    02 CRF450R
    06 CRF450X
    Image
    Weiser , Idaho
  • mustangnut
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    Joined: Sun Jan 28, 2018 11:04 am

    Re: Keihin needle seat-- how to remove?

    by mustangnut » Fri Jun 08, 2018 1:26 pm

    The main jet screws into the "needle jet holder" (an emulsifier tube) which screws into the bottom of the carburetor. The needle seat is pressed into place above the needle jet holder. It is #3 on the diagram I have linked to below:

    http://fiche.worldofpowersports.com/yel ... CARBURETOR

    The top of the needle seat pokes into the throat of the carb and can be seen just below where the carb piston rests. I suppose I could go through the top of the carb with a wood pencil or something of the sort and tap it out(?)

    Thanks for the tip--- I sent Leardriver a message and asked if he could take a look. I'm pretty new here so didn't know best place to ask. Guess Jetting works best for all carb questions.
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    JimDirt
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    Re: Keihin needle seat-- how to remove?

    by JimDirt » Fri Jun 08, 2018 2:59 pm

    That is a new one to me :-k , usually on those type of carbs (pretty much all motorcycle carbs) The Seat is in a separate hole that the main gas line flows to and is usually surrounded by 2 posts that hold the pin to the float , the "slide needle" comes down from the slide and goes into the Needle Jet which is what should be what is sticking up thru the venturi , the raising and lowering of the slide control the gas that is sucked up into the venturi , not the Seat , the Main Jet screws into the Needle Jet , neither the Needle Jet , nor the Main Jet have anything to do with the "Needle & Seat" . they are strictly for the fuel flow , and fuel would never be directly flowing thru the main jet from the Needle & Seat 8-[
    02 CRF450R
    06 CRF450X
    Image
    Weiser , Idaho
  • mustangnut
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    Re: Keihin needle seat-- how to remove?

    by mustangnut » Fri Jun 08, 2018 3:11 pm

    I believe we are talking about the same thing, but I was using the terminology from the diagram. I have seen it called needle jet elsewhere. The slide raises the needle, controlling fuel.

    So do I replace the needle jet by tapping it out with a dowel or something?
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    JimDirt
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    Re: Keihin needle seat-- how to remove?

    by JimDirt » Fri Jun 08, 2018 4:51 pm

    Again , the part that goes to the Float Needle , is not part of the Main Jet and should not be sticking up thru the venturi , it would be off to one side of the body (wherever the fuel inlet pipe is) and have the posts i mentioned and house the Fuel Needle , which has nothing to do with the Main Jet or Slide Needle or Needle Jet .. can you post a pic of your carb ?? (upside down , so i can see the location of the components) , i am not sure we are talking about the same part . as the Needle Jet is what should be sticking up thru , not anything to do with the Fuel Needle Seat , 2 separate parts

    To post a picture you need a hosting site like Imgur or some hosting site , you upload your picture to it , then click on the picture and it will show several links , pick the one for Forums/Message Boards , then copy the link to the picture into your post

    It will look like this when you paste it in your post

    [img]https: //i.imgur.com/PaWWmGG.jpg?1[/img]

    But it will show up like this (yes that's me , don't laugh , i'm old)
    Image
    02 CRF450R
    06 CRF450X
    Image
    Weiser , Idaho
  • Aussiecrf230
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    Re: Keihin needle seat-- how to remove?

    by Aussiecrf230 » Fri Jun 08, 2018 8:13 pm

    From memory I used a biro body to tap out the jet that came with the new needle. That was for the PD on the 230 anyway.
    Ray
    Australia

    CRF230F 2004
    C30F Power Up needle
    Mains 132
    Idle 45
    2 turns out
    Baffle out, Screens In

    It starts,it runs,it gets to where all CRFs can get to without the valve or valve plate dramas
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    JimDirt
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    Re: Keihin needle seat-- how to remove?

    by JimDirt » Fri Jun 08, 2018 9:27 pm

    From memory I used a biro body to tap out the jet that came with the new needle. That was for the PD on the 230 anyway.

    What do you do ?? , take the whole pen and push it down from the top by hand ?? , what is the reason to use a pen rather than say a Phillips screwdriver or a tapered punch ??

    And isn't the Needle jet the part that sticks up thru , so wouldn't it just unscrew ?? , the Float Needle Seat can''t be removed that way can it ??
    02 CRF450R
    06 CRF450X
    Image
    Weiser , Idaho
  • Aussiecrf230
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    Joined: Fri Jan 06, 2006 11:11 pm

    Re: Keihin needle seat-- how to remove?

    by Aussiecrf230 » Sat Jun 09, 2018 4:13 am

    I assume we are all talking about the needle jet that pokes up through the carb body that the needle moves in an out of! Used the plastic pen to tap out the old as we are only talking brass jet in alloy carb body. You could press it out with what takes your fancy. The main jet holder screws in to carb body and holds it in so should be removed first. Heating of carb body might help budge it.
    Ray
    Australia

    CRF230F 2004
    C30F Power Up needle
    Mains 132
    Idle 45
    2 turns out
    Baffle out, Screens In

    It starts,it runs,it gets to where all CRFs can get to without the valve or valve plate dramas
  • Back2-2
    Posts: 650
    Joined: Tue Jan 04, 2011 3:31 pm

    Re: Keihin needle seat-- how to remove?

    by Back2-2 » Sat Jun 09, 2018 5:47 am

    I believe we are talking about the same thing, but I was using the terminology from the diagram. I have seen it called needle jet elsewhere. The slide raises the needle, controlling fuel.

    So do I replace the needle jet by tapping it out with a dowel or something?
    Your terminology is correct, That is the needle jet and needle jet seat.
    The seat is press fit into the carb body. Unless yours is damaged which is very rare, I would not replace it. A small piece of scotch brite used to polish the seat is all that should ever be required to clean up the seal area. The needle has the rubber tip to make the fuel tight seal. If the seat is damaged, then yes it has to be tapped out and the new one pressed in.
    Hope that answers what you were asking.
    Neil
    Scottsdale, AZ
    "It's all about motorbikes - Always has been, always will be"
  • mustangnut
    Posts: 20
    Joined: Sun Jan 28, 2018 11:04 am

    Re: Keihin needle seat-- how to remove?

    by mustangnut » Sat Jun 09, 2018 5:52 am

    I assume we are all talking about the needle jet that pokes up through the carb body that the needle moves in an out of!
    Yep, that's it. I gave it a thump with a wood pencil from the top and it moved a bit. Never replaced one before, but got the idea now. New one comes with the needle so I'll replace it.

    Thanks everyone for the help!
  • Aussiecrf230
    Posts: 1401
    Joined: Fri Jan 06, 2006 11:11 pm

    Re: Keihin needle seat-- how to remove?

    by Aussiecrf230 » Sat Jun 09, 2018 7:57 pm

    They can get damaged if the neeedle rubs but that shows other problems with the carb. Normally old age from fuel erosion as it passes through it and around the needle. If it comes with the kit then you may as well change it. Glad it started moving for you they can grow in there over time.
    Ray
    Australia

    CRF230F 2004
    C30F Power Up needle
    Mains 132
    Idle 45
    2 turns out
    Baffle out, Screens In

    It starts,it runs,it gets to where all CRFs can get to without the valve or valve plate dramas
  • Leardriver
    Posts: 315
    Joined: Wed May 05, 2010 10:33 am

    Re: Keihin needle seat-- how to remove?

    by Leardriver » Sun Jun 10, 2018 4:19 am

    Do you have a picture?
    I don't remember ever removing one of those.
  • Back2-2
    Posts: 650
    Joined: Tue Jan 04, 2011 3:31 pm

    Re: Keihin needle seat-- how to remove?

    by Back2-2 » Sun Jun 10, 2018 5:28 am

    Do you have a picture?
    I don't remember ever removing one of those.
    It is just the brass cylinder that the needle rides in. Most people do not remove and replace them due to complications that can arise from pounding out a press fit part.
    It's solid brass and does no wear out only need a little polishing up on rebuilds. Years ago when the needles did not have rubber tips and both parts were solid brass it was replaced as a machined set.
    Neil
    Scottsdale, AZ
    "It's all about motorbikes - Always has been, always will be"
  • mustangnut
    Posts: 20
    Joined: Sun Jan 28, 2018 11:04 am

    Re: Keihin needle seat-- how to remove?

    by mustangnut » Mon Jun 11, 2018 11:43 am


    Years ago when the needles did not have rubber tips and both parts were solid brass it was replaced as a machined set.
    I believe you are referring to the float needle with a rubber tip(?) I'm talking about the seat for the needle jet; the needle inside the throttle piston (or throttle valve or whatever is the proper term). I just noticed when you buy a new needle from Honda or a rebuild kit for the carburetor it comes with one.

    Have patience with me-- I have always been fortunate enough to just swap jets or shim a needle here and there. I've never completely rebuilt one of these carburetors before; I figured it would be a good project this summer 8-[

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