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Vacuum leak? crazy rpms, and now it won’t start.

Discussion in 'XJ Technical Chat' started by NikoRx, Dec 9, 2017.

  1. NikoRx

    NikoRx Member

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    So I am new to motorcycles, got an 82 XJ550 and have sunk a lot into it. I paid an elderly gentleman twice now who specializes in older bikes to do the carbs in August. I believe he did not change the throttle shaft seals but am not sure how to tell without taking them apart (he was hospitalized before he worked on it, and forgot to put some screws back after working on it). I don’t have any more money to take it back to him and now the bike won’t start up. Winter is here so I am winterizing the bike. When it was running I drove it a couple of times and when I was in my neighborhood, I had a new problem. When I pulled in the clutch the rpm would skyrocket. I thought the throttle might be sticking and double checked it and it was not. Only started happening when the bike was warmed up and the choke was off as well. I sprayed some starter fluid on the carbs and it definitely shot up when I sprayed the throttle shafts. Any advice would be appreciated. I love this bike when I ride it and now I’m not sure why I can’t start it up or keep it running without some fresh Hell happening.
     
  2. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    You will have to replace the throttle shaft seals. The good news is that it sounds like the fella did a good job of cleaning he carbs othewise.
    You should also verify that he set the float levls corectly.
    The only parts you should need are the throttle shaft seals, which can be puchaced from member Chacal. Start a conversation with him.

    IN THE CHURCH OF CLEAN

    Replacing your Hitachi throttle shaft seals (Mikiuni carbs are simmilar)

    Setting the fuel levels

    There are more helpful links in my signature.
    Take an MSF course if you have not already done so, and get a copy of Proficient Motorcycing by David L. Hough.
    Be the Bunny, and ride safe.
     
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  3. NikoRx

    NikoRx Member

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    Thank you for all of that, and I have been reading through and seen Chacal mentioned numerous times. Is it better to show up to the mechanic with the replacement parts already purchased by me?
     
  4. Stumplifter

    Stumplifter Well-Known Member

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    NO!
    You are the mechanic.


    Sorry for shouting but seriously if you can open a peanut butter jar you can be your own motorcycle (XJ) mechanic... and you should want to be your own mechanic - it is your butt that will be swinging in the breeze when you get on those two-wheels. You sure you want to trust someone else to make sure that you are safe?

    Read those links that Kmoe posted, start asking questions here... keep asking questions until you FULLY understand the answers.
     
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  5. Jetfixer

    Jetfixer Well-Known Member

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    On the upper right corner of page is xj4ever this is chacal page to catalog of parts. You can do your carbs all you need are a few simple tools a Japennese screw driverlooks like phillips but is not. Chacal sells them . A flat blade screw driver and that is about it. you have to pull carbs off the rack and remove butterfly plates to remove shaft you will need a 10mm wrench . After you put them back together you will need to doa bench synch with either a playing card or small paper clip.
     
  6. hogfiddles

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

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    +1 to the above comments.

    I will add that if you want help, I do offer carb services. Just a few hours to the east of you in NY. Send me a private conversation if you want more info.

    Dave Fox
     
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  7. NikoRx

    NikoRx Member

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    I have tried to take the carbs apart to clean them and was extremely foolish and did not read the "in the church of clean" document before doing so. I would love to take them apart again and do the throttle shaft myself or even double check but they have supposedly been rebuilt (partially from my step dad and the older mechanic previously mentioned). I also don't have the right tools to sync them, I hear they are quite expensive.
     
  8. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Cheap as can be, and just as accurate for our purposes.
    how-to-make-a-2-bottle-synch-tool.15650
     
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  9. NikoRx

    NikoRx Member

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    So while I had the tank off of the bike this winter to work on it I came back out to the garage and noticed a basketball sized stain in the the ground. It appears the petcock has been dripping slowly. I did not have it set on prime or reserve tank so I thought it shouldn’t be leaking is that normal?
     
  10. hogfiddles

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

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    Should be no drips... it's not a Harley.
    I highly recommend taking a sniff at the oil filler cap to find out if fuel has polluted the oil or not. If no smell of gas, that's good-- shoes your floats and fuel needles are good. If it smells gassy you have carb work to do, as well.
     
  11. NikoRx

    NikoRx Member

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    I know our petcocks are of the vacuum variety and I believe the petcock may have been rebuilt not 100% sure anymore. could it be due to the top of the tank having a bad seal or do they not work like that. or is it just the petcock and I should rebuild/buy a new one
     
  12. NikoRx

    NikoRx Member

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    This is it taken apart what are your thoughts?
     

    Attached Files:

  13. hogfiddles

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

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    Yuck
     
  14. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    Rebuild the petcock.
    Did you ever finish the carb work that was needed?
     
  15. Jetfixer

    Jetfixer Well-Known Member

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    definitely in need of a rebuild kits are pretty cheap , I think I paid like 20$ for mine .... I bought a used petcock and rebuilt it as P.O. fitted an after market petcock that was ON/OFF/RES ....I love the vacuum feature on the stock petcock no more forgetting to set to off ( I'm paranoid about fuel leaking past needle valve and getting engine filled with gas ) .;)
     
  16. XJ550H

    XJ550H Well-Known Member Premium Member

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    if fuel leaks past the needle valves you have some carb work to do
     
  17. cgutz

    cgutz Well-Known Member

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  18. NikoRx

    NikoRx Member

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    Hey guys it’s been a while but now that school is taking a back seat I am taking the carbs apart. Going to end up buying a ton of new screws since some were rusted in place but I finally have the carbs apart. The throttle shaft seals... are those typically stiff and not as flexible as the o-rings? I assumed that was my main vacuum leak but am not sure because they don’t look as bad as the other o-rings. I also bought some carb rebuild kits and they came with this little metal donught piece and I cannot find where it goes in the carbs... any ideas?
     
  19. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    The throttle shaft seals should be supple and flexible. Yours are done. Get new ones.

    Post a pic of the 'little metal doughnut piece"
     
  20. DarthBob

    DarthBob Member

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    I think the little metal donut is a washer for the mixture screw, there should be one for each carb and a corresponding 0-ring.
     
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