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Dyno was perfect, but still coughs, spits etc...

Discussion in 'Technical' started by rowdy13, Jan 7, 2008.

  1. rowdy13

    rowdy13 Active Member

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    Took my K-9 in to get the easy clutch put on, and again reminded them that my bike upon starting, coughs, dies, backfires etc.... This time they put it on the Dyno machine (cant remember what its called). went to pick it up, and I started it, and it , as usual, coughs, dies, spits, backfires.....they showed me the dyno readout, and it was almost perfect. they said they tried everything, and said its just cold natured. I guess I should just accept the diagnosis and learn to live with it. dont know anything else I could try. By the way, so far the easy clutch is amazing. I can pull it in using two fingers.
     
  2. Chopper Dave

    Chopper Dave SIICK!!!

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    well....what kind of numbers did you hit?
     
  3. slowrower

    slowrower 2007 Mastiff

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    Do you use the enricher? .. could be the fuel, or carb issue - unless you have jacked the compression past 11:1 or so something must be wrong. Our motors don't like it cold and they do take some time to settle down while warming up but you should not be having this problem.
     
  4. KRAUT

    KRAUT Member

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    When cold- I open the petcock and wait 10 sec to make sure fuel bowl is full. Pu the enrichener lever. Blip throttle twice. With throttle closed hit starter button. When engine starts I increase the throttle and close the enrichener. To long with the enrichener will foul the plugs. Try this and see what happens-let us know.
     
  5. Vegas

    Vegas Well-Known Member

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    I always start mine with no enrichener and take it up to 2000 rpm for a little while until it idles well at a good idle. Gets the oil flowing and keeps the plugs clean. By the way a dyno graph has absolutely nothing to do with a starting problem.
     
  6. HDLARRY

    HDLARRY Active Member

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    I don't think it's to unusual for a carburated bike to run rough, cough and spit until warmed up. Mine does the same thing. I only use the enrichener for a couple seconds until started. Using it much more is asking for fouled plugs.

    If it was a fuel injected bike I would say you have a problem with the cold starting/run program.
     
  7. lee

    lee Well-Known Member

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    I don't use the enrichener at all - even when cold - i don't even have the enrichener lever on it at the minute - just a couple of blips on the throttle before starting - I have the throttle closed when I start - does it run ok when it gets going? is your idle speed and mixture correctly adjusted? remember the conditions on a dyno do not represent real life and just because it runs well on the dyno does not mean it will run well on the street
     
  8. 05chop

    05chop Well-Known Member

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    Lee Is right Dyno only show results for when your in the main jet.WOT.Dyno is a good tool for checking low power but like lee said not a good tool for a lower jet problem. 05chop:flag:
     
  9. Fibersnake

    Fibersnake Banjo Playing PsychoBilly

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    "Dyno only show results for when your in the main jet"

    Well for the most common used dyno (Dyno-Jet) based on inertia of the calibrated rollers this is true. There is other type of dynos though that will allow a good tech be able to see everything that is going on at all speeds and loads.

    Seldom used in the typical motorcycle shop or for that matter even the common local auto tuner, is brake dyno, be it through the use of eddy brake, water, or even friction, but any good brake dyno in the right hands, will allow the tuner to nail conditions much more accurate than inertia dynos.

    Brake dynos are more commonly used in engine shops and manufactures where they are able to control the load over the whole operating range and thus indentify and adjust for each load/speed range. Also commonly used in racing and particular road circuit type racing where the load various.

    If you want to get a very accurate dyno run that will give you a much better idea of what is going on throughout the range, find a dealer that has true brake dynos. For EFI equipped vehicles, use of brake dyno is really the only way to nail it (check out S & S Tech, they even mention it).

    It is very hard to see what the4 motor is truly doing when you do a quick WOT throttle run against a calibrated roller, however if you can brake it and hold the speed increments, you can see and thus adjust for each load area from idel to WOT.

    One of the reasons they are not that common is cost-plus the skills of tuners that can set there and run a test cycle and make sense out of it.

    Here is a link to some good info on dyno from Land and Sea

    Dyno Tech Talk
     
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  10. 05chop

    05chop Well-Known Member

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    Back to the question rowdy posted.Took my K-9 in to get the easy clutch put on, and again reminded them that my bike upon starting, coughs, dies, backfires etc.... This time they put it on the Dyno machine. Dyno jet is what I have seen used in the motorcycle shops only.All these guys do is check wot hp and torq.Looking for the correct AFR.Not sure why they even put it on the dyno to start with. Dyno jet is not used for checking start up coughs. 05chop
     
  11. P8RIOT

    P8RIOT Well-Known Member
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    Wow - great site, Fibersnake - if nothing else, it makes clear what a high-tech activity this is, and how sensitive the results can be to such things as temperature and atmoshperic pressure.
     
  12. LamboV12

    LamboV12 Active Member

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    Rowdy
    Do u know the project number on your bike?
     
  13. rowdy13

    rowdy13 Active Member

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    if the project number is on the dyno readout, I forgot to get it. I'm going back tomorrow to get a copy of it. the mechanic did tell me that out of all the bikes he services, mine has the most problems. went riding today, and while turning a corner, and then accelerating, it died for a second, or maybe I should say coughed, and when it picked back up, it almost threw me off. I'm wondering if this is something that I should contact Wichita about? I know these things are sensitive to cold weather, but mine started doing it right after I took it in for the 2500 mile checkup. and it was very warm outside then. before that, it ran perfectly, and i was very happy with my bike. Sul I think said it before, if your bike is running good, and you take it in for service, DO NOT let them finger with the carb. The tech thats working on mine, is doing everything he can, but there has to be something else. F=okie, how do you like the tulsa big dog guys?
     
  14. rowdy13

    rowdy13 Active Member

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    Oh yea, I keep smelling gas now. I was cleaning the bike last night and smelled gas. I thought it was coming from a gas can in the garage, but it was coming from the bike. I also smelled it at a stop sign while riding today. I appreciate all your responses.
     
  15. Vegas

    Vegas Well-Known Member

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    Do you have gas coming out of your clear overflow hose on your carb bowl? (Two seperate issues)Sounds like the tech may have adjusted your accellerator pump to cause you cough.
     
  16. rowdy13

    rowdy13 Active Member

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    dont know yet Vegas. I'm going to get a closer look in a little while. again, I thank everyone for responding. also, didnt get a chance to say welcome back to Fibersnake. I hope you are gettin' "all up" in your guitar!
     
  17. Fibersnake

    Fibersnake Banjo Playing PsychoBilly

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    Rowdy,

    Thanks for the welcome back, yes I have spent allot of time relearning (though how much I knew before can be questioned) the guitar.

    Now that the weather is giving a little glimer of niceness, I have spent a good part of the day preparing it for what I hope will be a good ride on Tuesday since it will be close to 70 here. Of course it will be back down to the 40 or lower within a few days.

    Grab it while I can.
     
  18. LamboV12

    LamboV12 Active Member

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    Rowdy - the project number is on the neck - should start with a letter like Y. followe by about 5 numbers.

    I suspect you have a carb issue or debris in the carb. Depends on your thoughts about warranty - but if it were me, I get an upgraded carb, like a triple X, or whatever. I would also pull the tank, fuel lines and blow them out with compressed air before putting in the carb.

    Then if you still have probs, look to changing the ignition. If you do both I guarantee it would resolve the problem -

    If your project number is near mine, I may be able to offer you assistance.
    Sent it via PM.
     
  19. BWG56

    BWG56 Guru

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    Looks like there's a few of them, I thought the same as I was reading thru the old posts. I guess there's not much change when it comes to Carbs.
     
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