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Can running lean damage my bike?

Discussion in 'XJ Technical Chat' started by JoshuaTSP, Aug 27, 2009.

  1. JoshuaTSP

    JoshuaTSP Member

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    :?:

    Can it?
     
  2. lowlifexj

    lowlifexj Member

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    Well that depends on how lean your bike is running. Post some pics of your plugs that would help. These bikes run lean from what I've seen anyway. As long as your not burning off plugs or have spark knock, lean is fast... A richer running bike is better on the engine but doesn't make the hp.. My bike has over 41k miles on it and I run light gray with a little tan in my electrodes.. I'd rather blow up than be beat by my friends HD and we are dead even right now..
    James
     
  3. That_Guy

    That_Guy Member

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    Basicallt it come down to if you expect it running lean it probably is running extremely lean (they were tuned lean from the factory).......so yes it will cause your engine to overheat and can cause some major problems
     
  4. SQLGuy

    SQLGuy Well-Known Member

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    Biggest problem would be if the mixture suddenly went lean under high load, like something blocking the main jet while you're at WOT at 7K RPM. At that point, the combustion temperature, airflow, and force of the other working cyinders carrying the suddenly lean one could cause the cylinder to start burning aluminum - i.e. burning the piston, the head, etc.
     
  5. JoshuaTSP

    JoshuaTSP Member

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    Well, I know 2 of the 4 are running lean, white plugs and bluing pipes.

    I know I need to check the valves and it really needs a major carb cleaning, but I want to wait until the riding season is over before I dig in. Since I just bought it a few months ago.

    Just want to see if I'm damaging the bike just riding it now.
     
  6. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    If it's lean enough to be bluing pipes it's lean enough to be doing other damage as well. You don't want to hole a piston (or two.)
     
  7. JoshuaTSP

    JoshuaTSP Member

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    Anyway, to "clean" the blue off the pipes?

    Since it seems to be running a lot better lately?
     
  8. helmet

    helmet Member

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    On 2 wheels... just lost my hat.
    there is something called blue away or something that is supposed to take care of that.
     
  9. JoshuaTSP

    JoshuaTSP Member

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    I'm going to have to check the plugs tonight too....just to see if they've changed color since the carbs were slightly de-gunked.
     
  10. SQLGuy

    SQLGuy Well-Known Member

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    Generally, if it's going way lean under load (i.e. with high enough cylinder temp to cause damage), you will see little specks of metal on the very white insulators of the plugs.
     
  11. JoshuaTSP

    JoshuaTSP Member

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    Thanks!

    That I didn't see the first time I checked the plugs. Just two white plugs, one tan, and one black.

    That was back before it started idling without choke on all the time. All of a sudden, one day it idled perfectly at 1050 and ran a lot smoother. The Seafoam treatment must have cleared something out.
     
  12. WildWanderer

    WildWanderer Member

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    My bike runs lean.

    I rode it from Pittsburgh PA to Chico CA.

    It's still running.

    With these bikes, you can go nuts trying to tune them to perfection, or just say awww f*** it, and ride it the way it is.
     
  13. TIMEtoRIDE

    TIMEtoRIDE Active Member

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    Some guy on here showed us 2 holed pistons a while back, so be careful. I guess if you think you are too lean and still need to ride, you could just baby the bike around, if you needed it for transportation.
     
  14. JoshuaTSP

    JoshuaTSP Member

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    What are signs of "too lean"?
     
  15. RickCoMatic

    RickCoMatic Well-Known Member

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    Clean Spark Plugs
    Overly Hot Running
    "Using" Oil -- Needing to Top-Up frequently
    Stress Fractures on the ceramic surrounding the Center Electrode on the Plugs.
    Burned Valves
    Cooked Oil Smell
    Knocks
    Catastrophic Failures:
    >Rods
    >Welded through Pistons
    >Melted Combustion Chamber
    Engine Seizure
     
  16. helmet

    helmet Member

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    On 2 wheels... just lost my hat.
    a little duct tape will take care of that.
    :lol:
     
  17. JoshuaTSP

    JoshuaTSP Member

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    Any quick temporary fixes?
     
  18. Robert

    Robert Active Member

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    Tweak the fuel screws for the lean cylinders and watch the spark plugs. It's not rocket science.
     
  19. RickCoMatic

    RickCoMatic Well-Known Member

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    Running Lean.
    You have to know "How Lean" you are!
    Pull your Plugs and examine them. If you have Color on the Plugs its a good sign.
    If you DO NOT have Color; you need to rectify the situation ... immediately.
    On Plugs that are Clean. Use a Magnifying Glass and look at the Ceramic Tip surrounding the Center Electrode.

    If the Ceramic is eroded, cracked, stress fractured or pure white ...
    THAT is a sign of being "Critically Lean" and needing corrective adjustment to prevent serious damage from occurring.
     
  20. littlegiant

    littlegiant Member

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    Turning the Pilot screws alongside the start enricher slider (choke) anticlockwise make it richer.
     
  21. JoshuaTSP

    JoshuaTSP Member

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    Will that adjust all cylinder mixtures?

    It appears that only two of them are running lean.
     
  22. RickCoMatic

    RickCoMatic Well-Known Member

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    No.
    Each Carb has its own Mixture Screw.
    The Mixture Screws need to be > Tweaked < Not turned.
    The Mixture can be changed very dramatically within an adjustment to the Mixture Screw the width of a Nickel.
    Once the "Sweet Spot" is found a "Quarter Turn" could move you from too Lean through just right to too Rich.

    Adjust each Carb individually.
    If adjustments to the Pilot Screws do not solve the Mixture problem
    Check:
    Sync
    Diaphragm Pistons Sticking
     
  23. JoshuaTSP

    JoshuaTSP Member

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    Thank you for the help.

    I just got the bike this past fall. I was hoping to avoid pulling the carbs until winter. Since I wanted to ride so bad. The bike started well, but didn't idle well at first, and didn't have much power.

    I ran some seafoam through it, and it started to idle consistently....but still lacked any real power. It sure takes off if I bump up the enrichment circuit (choke) though. Wow.

    I checked the pulls after chopping them at idle, with enrichment on....since it wasn't idling cold. 1 & 3 were lean. Not completely white, but close.

    Couldn't trust that......so I took it out for a spin, hammered up to my driveway, then cut it.......must have gotten up to 4k-4.5k RPM before I cut it.

    1&3 were still a bit lean (tweaked those)......2 was grayish and 4 was sooty.

    So that's where I sit until I can tweak a little more or winter comes for complete carb overhaul.
     
  24. JoshuaTSP

    JoshuaTSP Member

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    Ouch.

    I just did a plug chop at about 5k under load......
    plugs 1 & 3 are white with brown specs.
    4 is sooty and was wet.
    2 was white.

    When I chopped them at idle, 2 & 4 were dark......4 being black.
    1 was light brown, and 3 was white.

    I cannot wait until I can work on this thing!
     

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