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cleaned/bench-sync'ed carbs. now what?

Discussion in 'XJ Technical Chat' started by oneuglybike, Oct 29, 2009.

  1. oneuglybike

    oneuglybike Member

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    Good evening everyone. So, as the title suggests, i just went through the cleaning and bench-sync'ing steps for my carbs and put 'em back on (81 650 Max). Based on all the threads i have read, my next step is to get'er going and adjust idle, pilots, etc until she's running like a champ.

    Life never works that way. I did briefly get the bike fired up (on 3 cylinders- 2,3, and 4) but she wouldnt idle and after about 10 seconds of keeping rpms around 2500-3000 with the throttle i let it go and it sputtered out. I have tried about 10 times since with no fire. at times pressing the starter button actually appeared to do nothing at all- no turnover or delayed turnover. The "good" news is that prior to cleaning the carbs it ran on 3 cylinders, but 1,2, and 4 (so theoretically i "fixed" number 3 in exchange for number 1).

    some notes in no particular order: compression is good on all cylinders but i haven't pulled the head off. i have a feeling that my carbs on not sealing to thier boots attaching to the engine itself. rubber looks good, it just seems like they may be moving. I have my mufflers off- headers only right now- #1 (the one that doesn't fire) seems to be ejecting white (smoke, spray?) out of the pipe, but it isnt firing for sure. Other than replacing the sparkplugs, cleaning the carbs- pilots set at 2 and 1/2 turns-, replacing the battery and changing the oil i haven't done anything to the mechanicals of this bike (of course, i have a long way to go).

    Finally, on one of the attempts to start after my initial start, cylinder 1 (again, the one that doesnt fire) appeared to "backfire" into the carb and puffed some smoke out of the boot/carb seal.

    So, what should i look at next to get this thing going? Can you guys suggest something to seal my boots to the carbs to prevent the air leaks that are likely causing some of my problems? Do you have any fixes for any of the symptoms that i described?

    long post- my bad. Thanks everyone-
     
  2. wizard

    wizard Active Member

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    I guess you should check the valve clearances are all in spec', first.
    The metal clamps should secure the boots to the carbs.
    If you have cleaned, bench synced & set the float levels correctly, the bike should run, maybe rough, once running you have to vac sync' the carbs, then you can adjuct the pilot mixture screws using either plug chops or color tune.
    With the plugs out & laid on the head, are you getting a fat spark on all 4?
    Keep the battery fully charged at all times.
     
  3. RickCoMatic

    RickCoMatic Well-Known Member

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    The Intake Manifolds are "Dry-mounted" to the Head.
    IF the Manifold Bolts are seized it will be impossible to replace the Manifold O-rings,

    Take the Carbs off and add a "Bead" of RTV Sealant to the Manifolds.
    Put a dab on you fingertip and wipe it IN TO the joint where the Manifold meets the Head.
    Make the Manifolds completely air tight to the Head.
     
  4. TIMEtoRIDE

    TIMEtoRIDE Active Member

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    Your #1 carb is flooding. You can confirm that with a piece of clear tube using the drain screw. Check all 4 float levels with carbs on the bike- - 3 MM below the bowl gasket surface. You'll have to average this, as the carbs are slightly tilted.

    To fix without taking apart- - TAP (don't pound) with a rubber mallet or a 2X4 about 20 - 30 times. This simulates engine vibration. Re-test as above.
    You may need to drain and tap, refill and check.

    The intake manifolds appear to "breathe" a little at idle- - normal.
     
  5. oneuglybike

    oneuglybike Member

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    great, thanks guys. i am going to try starting her up again and will check the float level in carb 1 with the tube (I forgot to mention that i set all 4 dry at 17.5mm as described elsewhere on this site and bike is on centerstand). if all is well, i guess i get to see what the valvetrain looks like.

    As far as the bad seals i tried to describe above, my problem is where the rubber meets the carb. i have each metal clamp secured as tight as i can, but it seems like they arent doing thier job. i hope that the seals to the actual head is good- Rick you are giving me too many variables Man!

    again, thanks for your help. Someday i hope to give back to this site as you guys are giving to me.

    Mike
     
  6. oneuglybike

    oneuglybike Member

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    ok. if any of you guys are still listening, i have a few more questions.

    1: is there anyplace that i can get this clear rubber tubing for float-height testing quickly? i havent seen it anywhere and am not sure exactly what i should be looking for. Advance sold me a vacuum gauge, but the hose is black.

    2: TimetoRide, what exactly should i be hitting with a rubber mallet/2x4? (i'm getting ready to knock my head a few times, but i think the rubber will defeat the purpose...surely i have a real hammer around here somewhere..)

    3: Is it possible that my problem is not related to the carbs and fueling? what other problems might i be looking at? its been a busy weekend, but i plan to pull the head cover off tonight and take a lookyloo at the valve clearances.

    thanks-
     
  7. oneuglybike

    oneuglybike Member

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    i realized that i didnt answer all questions- to my untrained eye, spark at all plugs looks good. thanks again,

    Mike
     
  8. oneuglybike

    oneuglybike Member

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    released all the hardware holding my head cover on but it is frozen. looks like i need that rubber mallet after all. cool, i get to go to Lowes.

    reading through other posts and i read that if carbs overflow, gas could get in the oil. I decided to drain mine just to be sure, and it doesnt look like that is a problem (would it be obvious?).
     
  9. wizard

    wizard Active Member

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    Clear plastic tube, hardware shop or aquarium store.
    use the wood to TAP on the float bowls, not hard, gently.
     
  10. Bushy

    Bushy Active Member

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    If theres gas in the oil it will smell like gas/petrol.
     
  11. TIMEtoRIDE

    TIMEtoRIDE Active Member

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    Ace is the place for lawnmower clear fuel line by the foot.
    You tap no harder than if your finger were in the way. Practice !!
    Try not to hit the enrichment parts. Safe to hit the steel bracket.

    To answer #3, it would be easier for us to diagnose a running bike.
    It ran before- - get it running, do and check all that's mentioned in this thread, and get back with us with your new list of symptoms.
     

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