Stranded on the road, need help

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by 35xj, Jan 19, 2013.

  1. 35xj

    35xj Been here awhile

    Joined:
    Oct 30, 2008
    Oddometer:
    961
    Location:
    asheville, nc
    Almost in Huntsville, al

    04 950. 34 k on it. Faccet do. Recent valve check.
    Bike is behaving like its running out of fuel sporadically
    Doesn't sputter or die, but stutters and looses power
    Idles fine, runs well at low speed, won't run well above 50
    Continuously.
    Bypassed fp made no difference.

    N
    Red some help on what is wrong

    Help please!
    #1
  2. Dru

    Dru Hardly an Adventurer

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    Check the fuel filter for clogging? Vapour lock?
    #2
  3. Dusty

    Dusty Long timer

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    Vent lines for the carbs?
    If the canisterectomy was done the 2 bowl vents need to be through the bottom of the air box between the cylinders. Out of turbulent air.
    #3
  4. scruffy

    scruffy Been here awhile

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    +1 I did the valves on mine and left the vent hose out to open air and same symptoms, rerouted the vent hose back between the cylinders fixed it.




    #4
  5. jclark83

    jclark83 Been here awhile

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    Could be a split carb diaphragm.
    #5
  6. booger1

    booger1 Been here awhile

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    Hows the air filter? Happened to me once on my zx9r, I put too much oil on the K&N filter. Ran fine on the bottem end but was terrible on the top end. The shop that I took it to had a real good laugh.
    #6
  7. 35xj

    35xj Been here awhile

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    air filter is good, vent hoses are kinda in the area of air flow. ill move them tomorow.

    tell me more about the split carb diaphram?
    #7
  8. Katoom119

    Katoom119 Mmmm....Orange Kool-aid

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    It has to be some kind of vacuum lock. The fp can't pump enough fuel to the carbs against a suction. When you put it back together you may have pinched a vent hose.
    #8
  9. 35xj

    35xj Been here awhile

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    plan to tear into it tonmorow morning. the problem is strangely sporadic, the bike will run well for a while, although generally feels down on power, kinda feels like a miss possibly?

    plan tomorow is to take it back apart, pull the carbs and look it iver. check carb boots, plugs,coils, etc

    bike is also running a higher than normal idle (2K) or so, lots of popping backfiring. Temps are fine, no obvious leaks etc
    #9
  10. jclark83

    jclark83 Been here awhile

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    The throttle cables open the butterflies on the carbs. The black slides that carry the needles are operated by vacuum via the diaphragms. They are located under the black covers on the ends of the carbs. With age they develop cracks that cause a vacuum leak, causing the black slide to not fully open. If your problem didn't start immediately after service work this is where I would look. I had a similar issue and found one of mine split. If you have a split diaphragm I would replace both of them. Good luck and keep us posted on what you find out.
    #10
  11. 35xj

    35xj Been here awhile

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    the problem did start within 100 miles of service, leads me to hope/believe its something stupid i did.

    Its wierd, because the problem has become much more prevalent as the day has gone on. the bike is now running high idle and popping like crazy.
    #11
  12. jclark83

    jclark83 Been here awhile

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    Maybe you didn't get your carbs fully seated in the boots and one of them has come out of the boot? High idle and popping points to a vacuum leak or fuel supply problem.
    #12
  13. Katoom119

    Katoom119 Mmmm....Orange Kool-aid

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    +1
    #13
  14. dlrides

    dlrides 1:1.618

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    Check carb boots, vent/vacuum lines. Sounds like something simple missed during service.
    #14
  15. Dustodust

    Dustodust Long timer

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    +2
    #15
  16. jclark83

    jclark83 Been here awhile

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    Any updates?
    #16
  17. 35xj

    35xj Been here awhile

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    pulled it apart today, both plugs are brown and dry, no obvious kinked vents, carb diaphragms look fine, fuel lines appear to be flowing fine. carbs well seated,no cutsin boots,etc nothing looks obviously wrong.
    Smoke, some residue on rear cylinder exhaust from crank case breather being moved to a seperate filter at back cylinder. Rear cylinder(one i changed shims in) nothing obvious, everything still in spec.
    Oil level looks good, coolant looks good, throttle, choke cables all moved freely.

    Kinda stumped at the moment, not going to push my luck with it. going for the "ride of shame" tomorow in the bed of a truck!
    both plugs looking so lean(did not look dry/brown at service) leads me back to a fuel delivery issue. fuel pump? as far as the smoke/chain rattle, we shall see!

    i will update as i discover the issues for future reference!
    #17
  18. 35xj

    35xj Been here awhile

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    incidentally, if you stay up most of the night, researching the internet to try to figure out what the hell is wrong, you will be amazed/horrified at the potential "certain resolutions"
    at one point i think it appeared that my bike had the crabs:lol3
    #18
  19. Navin

    Navin Long timer

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    I had to pump my fuel via mouth air pressure thru the vent tube when my pump went out. Is your pump moving fuel?
    #19
  20. 35xj

    35xj Been here awhile

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    pump is moving fuel, fairly consistantly( pulled the outgoing hose, and let it pump, seemed to be ok) but im going to replace it,and then ill know!

    here we go! ordered new fuel pump(another facet) and filter, h2w jettingkit with prefilter etc. new fuel hoses.Plan to get the fuel delivery as correct as possible, then try to figure out what else is wrong with it!
    researched the oil pump spring etc this morning.
    Hopefully, going through the fuel pump/jetting stuff, it will run well enough to try to diagnose the rattle issue.

    Any thoughts on what else i should look into while its apart?
    #20