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XJ650 Seca Seized Engine Help

Discussion in 'XJ Technical Chat' started by Rebem, Jul 28, 2016.

  1. Rebem

    Rebem Member

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    So here are a couple of photos to show progress. I'm still having a hard time with stuttering at low revs so I'm worried about the plastic I saw coming off the floats and it might be time for a new set. Has anyone had their floats perish and crumble before?

    XJ Side View.jpg XJ Tank View.jpg
     
  2. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    Typically, the Hitachi floats are pretty indestructible, but if they are starting to flake apart (or have large chunks missing from them, then it might be time to replace them............we do have new and good used floats in stock, and of course can fly them right over to you!
     
  3. Rebem

    Rebem Member

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    Thanks Chacal. Considering ripping the carbs off again and I'll check the state of all 4 floats and get back to you.

    Before I do that I've been removing the spark plugs and adjusting the mixture based on what I see. Initially all 4 were black and sooty so I reset the screws to 2.5 from soft-bottom as a starting point. So far I've had to lean (turn in clockwise 1/4 turn at a time) each of them off significantly. I'm at 1.5 from soft-bottom for #1 and #2 and they're still sooty. #3 and #4 appear ok around 1.75 turns. This feels like a long way in. Is there anything odd about that?

    My symptoms are the same - very little choke needed (and not for long) and once the engine warms up, I get severe spluttering on take-off through to about 3,000rpm when the main jet kicks in I guess. So just querying my next steps again with you please guys :
    - Keep going with the 1/4 turns to lean out cylinder #1 and #2
    - Pull the rack and double check all the pilot circuits and maybe float levels again?

    Here's a photo of the plugs but #1 and #2 (left) are a lot blacker than the photo shows. Maybe #3 is a touch lean now?
    IMG_20171210_140954.jpg
     
  4. hogfiddles

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

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    Are you using hitachi jets or aftermarket ones?
     
  5. Rebem

    Rebem Member

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    Stock standard Hitachi. Checked the numbers against the jet numbering at the Church. I have an aftermarket 4-1 exhaust but I thought that would have the opposite effect on the mixture at idle?
     

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