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Xj750 CARBURETORS

Discussion in 'XJ Technical Chat' started by Codysc843, Mar 24, 2020.

  1. Codysc843

    Codysc843 Member

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    So I've got the bike running with no carbs when I stuff a gas soaked rag into the intake on the motor itself I cleaned the jets (small jets wouldn't allow a cleaning tool to go through) I used a can of carb cleaner, the bike won't run still what's wrong with the carbs any ideas? Idk where to buy a brand new set
     
  2. Codysc843

    Codysc843 Member

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    Also yes they're bench synced
     
  3. Simmy

    Simmy Well-Known Member

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    I would suspect they are gummed up.
    There are tiny passages in the body which can get plugged and the only way to clear them is to completely submerge it in a strong cleaning solution, an ultrasound tank helps. Time for:

     
  4. jayrodoh

    jayrodoh YimYam Premium Member

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    Don't take this comment poorly but you have 4 threads now on the same issue. You should keep the conversation within one so that new readers can see the history and offer their feedback intelligently. When you post to the old thread it will pop to the top of the forum for new readers to see. This also alerts others that have commented on your previous threads that there is new information.

    That said. If it runs when you dump a bunch of fuel in the intake by spray or put an extremely rich mixture in (i.e. gas soaked rags) you are confirming that you have spark. It still sounds like carbs are an issue BUT we'd love to see your compression numbers and valve shim clearances. If you have low compression it may still fire but it won't run properly and you need vacuum from the motor for the carbs to work. In another thread you commented that it has been run for 5 minutes without oil, I would really like to see the compression numbers now that we know that. Valve clearances will lower compression if ignored and are too tight.

    You most likely won't find any, and if you did they would probably cost more than 3 to 4 times what a professional rebuild would. There are guys that restore carbs to better than new for a reasonable price, I've had many sets done. I wouldn't spend that money until you go through the other tests and determine the state of the motor.

    She won't start if those are clogged. See the link provided, much information on how to clean and test those.
     
    k-moe likes this.
  5. Huntchuks

    Huntchuks Well-Known Member

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    If the enrichment tube jets are clogged, the engine will not want to start. Spray carb cleaner will not do the trick, you need to use a wire.
     
  6. Codysc843

    Codysc843 Member

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    Same bike different issue therefore new thread but ok I'll leave all issues in this thread I'll tear down the carbs later tonight or tomorrow and soak everything in carb cleaner. Question after soaking do I rinse them water gas etc or wipe each part or shoot compressed air on everything and through the jets? Or just simple soak and reinstall after sitting overnight
     
  7. Simmy

    Simmy Well-Known Member

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    You need to strip everything off the body.
    The body should be void of everything.
    Soak them for a couple hours, blast the passages with air then soak them again.
    Blast them with air again, then spray carb cleaner through the passages. Then reinstall the jets, o-rings etc.
    You need to allow many hours for this.
    Did you read everything in the church of clean?
    You need to order replacement parts before they go back together. New screws for the butterflies are highly recommended, throttle shaft seals . It’s a big job but must be done right
     
  8. Codysc843

    Codysc843 Member

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    Man one of yall just clean a carburetor and ship it to me I got money ready for em don't tax too much ready to have this bike done
     
  9. Simmy

    Simmy Well-Known Member

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    @hogfiddles will rebuild them for you if you’re not willing to tackle this. These carbs are nearly 40 years old. They don’t need a cleaning, they need a rebuild.
     
  10. Codysc843

    Codysc843 Member

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    These are hsc32 hitachi carbs correct? 1982 xj750 maxim just wanna make sure cause I'll be ordering a rebuild kit also the small brass tube that's next to the jets what's that and how do remove them
     
  11. Simmy

    Simmy Well-Known Member

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    The tube you’re referring to is not removable.
    The commercial rebuild kits do not include throttle shaft seals or the fuel tube o-rings.
    Tear them down and you will see what is needed before ordering.
    The carb bodies need to be completely stripped before dunking them. Any solution strong enough to do the job will destroy the rubber components. This is all explained in the church of clean.
    Do it all, don’t cut any corners or you will be doing it all over again. This is not a 1 or 2 evening job.
     
    Timbox and jayrodoh like this.
  12. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    And I HIGHLY recommend you get the complete deluxe rebuild kit from Len Chacal. That is the ONLY source I use. All others gave me nothing but grief. Get the right parts the first time.

    dfox
     
  13. Codysc843

    Codysc843 Member

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    My question was what model carbs comes stock on these 82 maxim xj750 I think its hsc32 Hitachi right
     
    Wingedwheel likes this.
  14. jayrodoh

    jayrodoh YimYam Premium Member

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  15. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    On all up-to’83
    xj650 maxim/Seca, xj750 maxim/Seca

    the carb bodies and racks are the same.... it’s the jetting that’s different between them
     
  16. Codysc843

    Codysc843 Member

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    If the carbs worked before I had relay and wire issues now that relays and wires are fixed what could all of a sudden go bad in carbs?
     
  17. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    You mean like this?
    https://xjbikes.com/forums/threads/owww-my-eyes.112790/

    Well, reading all the way back to the beginning of the thread, it seems to me that YOU are the one that’s been questioning the carbs right from the first post. Maybe I’m just missing something here.....

    dfox
     
  18. Codysc843

    Codysc843 Member

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    Naw your misreading. I'm asking a question in that comment not debating or making a statement it's odd to me how one day carbs work next day they don't and I'm asking what would go bad all of a sudden?
     
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  19. Codysc843

    Codysc843 Member

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    And yeah them carbs look pretty good how much for a set? Any discount if I ship you my set to rebuild and resell?
     
  20. Codysc843

    Codysc843 Member

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    I'm thinking soak the carbs in gunk after I remove everything let it all sit in gunk overnight (except rubber components) then boil it all in water (to try and break up any loose rust or dirt) then another soak overnight and shoot air all over the carbs...never went this much in detail cleaning bike carbs what's yalls thoughts on my idea?
     

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