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Cold 1/3 headers

Discussion in 'XJ Technical Chat' started by splazoid, Apr 28, 2012.

  1. splazoid

    splazoid Member

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    Something's going on that the header pipes on 1 & 3 don't warm up. Sounds pretty terrible, and unburnt gas dripping from the collector box.

    I pulled the plugs on 1 & 3 and there is spark, but they're headers comfortably cold to the touch after 10+ mins of riding.

    Where do I begin? New plugs somewhat recently.
     
  2. mlew

    mlew Well-Known Member

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    You have carb problems, stuck floats are overfilling the carbs. Time to take them out and clean and rebuild. Are the plugs on 1 and 3 wet with gas? They won't fire if they are.

    Check your oil and see if it smells like gas, change it if it does.

    Check the valve adjustment while the tank and carbs are off.
     
  3. splazoid

    splazoid Member

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    I just completely rebuilt everything in the carbs, but there is a potential for a stuck float which I'll check.

    Brand new oil and filter, valves have been a fiasco, but should be sorted out now.

    I'll check the floats, thanks for the tips kind sir.
     
  4. mlew

    mlew Well-Known Member

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    Did you verify the float levels before you installed the carbs? The clear tube method works best.
    If you are sure the float levels are correct it is possible some trash is logged in the seats keeping them open. A few taps with a rubber mallet on the side of the carb can help to unstick a float. If that does not help then clost the petcock and drain the fuel bowls, open the petcock and try to flush out the trash. Repeat several times. In line fuel filters will stop that from happening again.
     
  5. splazoid

    splazoid Member

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    Yes, i used the clear tube method, and very meticulously checked the levels. It could very well be garbage in the bowls, but have used an in-line filter since the rebuild.

    Is there a potnential that leaving the fuel on prime could cause this? I noticed that after checking things over.
     
  6. mlew

    mlew Well-Known Member

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    Leaving the fuel on prime can cause that. It also means your float needles are not sealing 100%. Clogged jets could also be a possibility.
     
  7. adrian1

    adrian1 Active Member

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    While it sounds like you thoroughly checked your float levels I tink you need to re-via it them again
     
  8. hogfiddles

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

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    If its 1/3, I'd be more inclined to look at a coil issue.........

    Dave F
     
  9. splazoid

    splazoid Member

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    See i thought that too, but when i ground a spare plug to the frame, it's got great spark on 1/3.
     
  10. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    The bike fires 1-4 and 2-3 off the same coils, not 1-3.

    If you have fuel dripping it has something to do with your floats. Leaving it on PRI just reveals the problem; if the floats were working correctly you could leave it on PRI and it wouldn't matter.

    You set the floats to Mikuni spec, not Hitachi, correct? I only ask because a preponderance of info on this site is for the bigger bikes.

    Did you replace the o-rings on the outside of the float valve seats? A leak there will look and act like a float issue.

    Go back and do a wet-verify on the floats. If you can get the bike level from side to side, and prop up the front enough to get the carbs level front-to-back, you can check (not adjust, check) them on the bike.

    You're going to have to find and solve the drippy carb issue, that's all there is to it.
     
  11. Kaya

    Kaya Member

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    Cant it fire it any way you wire it? Wasted spark?

    Maybe thats just XJ650s?


    -Kaya
     
  12. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    No. Yes.
     
  13. hogfiddles

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

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    Oops, my bad. After I hit send, I started thinking about that again, realized my mistake, but only am back to the keyboard. now.

    Please accept my apologies....hanging my head in shame, crawling home with tail between my legs. BAD dog, BAD, BAD, BAD ,BAaaaaaaAaaAAD. Go in your box.

    dave f
     

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