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Morning start issues.

Discussion in 'XJ Technical Chat' started by Glen F., Jul 27, 2021.

  1. Glen F.

    Glen F. Active Member

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    Hey all. Color tuned and synced again last night and the bike was running fantastic. Started first thing this morning with half choke. Started to drive and she started to bog down. Let it idle for a bit, and it seems like the warmer the engine gets, the better it runs. Why would it do this?
     
  2. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    A carburated engine has to warm up to run well.
    Keep the choke (enricher) on until the engine RPM starts to climb to about 2,000 RPM, then slowly back it off to drop the idle a bit.
    At that point you can ride, and then turn the choke off after a few minutes.
     
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  3. Glen F.

    Glen F. Active Member

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    Here's another interesting thing. Went for a good ride. Idles at about 1200. After 20 minutes or so, idle goes up to 2000. I'm hoping new shaft seals will solve that issue.
     
  4. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    That's normal. As the engine gets hotter the idle will rise because the fuel is being buned more efficiently.
    When setting your idle speed you'll want to find a good balance between reliable cold starts, and RPM being around 1500 - 2000 RPM when stopping after a hard ride. Your 2000 RPM idle is not an indicator of a vacuum leak at the throttle shaft seals, or anywhere else.
     
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  5. Glen F.

    Glen F. Active Member

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    That's good to know. I just don't remember what it did 27 years ago, so it seems kind of odd to me, but that's just me.
     
  6. JCH

    JCH Active Member

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    I use my choke as K-Moe says and after warm up my engine idle is about 1100 rpm as spec I believe.
     
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  7. Franz

    Franz Well-Known Member

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    My bike is the same. The fuel condenses on cold cylinders I understand so a richer mixture in needed to get it started.
     
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  8. XJ550H

    XJ550H Well-Known Member Premium Member

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    adjust your idle after 10 or 15 minutes of riding
     
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  9. Btroppma

    Btroppma Member

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    My 82 xj650 maxim is the same as well. Needs choke to start, but after a few seconds it can go down to half choke.
    A minute or two of riding, I can close the choke. When it's fully warmed up, the idle is rock solid at 1100 rpm.
    3rd gear + 7k rpm = :)
    Bob
     
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  10. Glen F.

    Glen F. Active Member

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    I've been doing as K Moe suggested, but it seems like it's getting too much fuel because it sputters and farts and boggs down. Then after it warms up, everything is good. She starts great. Gets to 2000. Let her sit for a bit and slowly reduce the choke.
     
  11. Minimutly

    Minimutly Well-Known Member

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    Bikes are for riding, not sitting there whilst warming up. Start it, make sure all is well, ride it, reducing the enrichment as you go. The age old advice to "warm the machine up on the stand before moving off" was nonsense.
    Just be gentle and kind until the oil is warm.
    Set the idle mixture and speed when properly hot.
     
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  12. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    If she's bogging then just reduce enrichment a tad.
     
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  13. Glen F.

    Glen F. Active Member

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    I tried that today. If I reduce it too much, it has a hard time keeping idle unless I keep reving the engine. Then when I take off it sputters and farts. I drive like that for a bit and kill the choke and it takes a good hit on the throttle to clear the sputtering and then all good.
     
  14. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    It’ll take a bit for you to get the feel of it. Keep in mind that ambient air temperature plays a big role in how much fuel is needed during warmup. It may be easier to let it warm on the stand for a minute or two, but it shouldn’t need much time doing that in the Summer.
    Typically I’ll start mine and by the time I have my helmet and gloves on it’s warm enough to start riding, unless it’s very cold out.
     
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  15. Glen F.

    Glen F. Active Member

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    Thanks k-moe
     
  16. cgutz

    cgutz Well-Known Member

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    On a summer morning, mine requires choke to start. Then by the time I get down the driveway, and the rpms are up on the street, I turn off the choke. Runs great after that.

    If it hasn't been run a few weeks, I might have to turn petcock to "prime" for a couple minutes to refile carbs (evaporation?), then turn it back to run.
     
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  17. Glen F.

    Glen F. Active Member

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    Started up fine this morning. Ran with the choke on for a bit and slowly cut it back. Bike almost stalled. Opened the choke back up and then it stalled. Couldn't get it started after that, so I pushed it back home, only a few blocks away. Put the battery on the charger because it didn't seem like it had much power when turning the bike over. See what it does after work.
     
  18. Glen F.

    Glen F. Active Member

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    Bike started up right away after work. Battery was fully charged and is at 13.31. 14.7 at 2500 and same at 3500. When I first took it off the charger and tested the battery, it was dropping very slowly without the bike running.
     
  19. XJ550H

    XJ550H Well-Known Member Premium Member

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    after charging battery will settle to12.8 volts. measure voltage in morning before starting and test voltage drop when turning over.
     
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  20. Minimutly

    Minimutly Well-Known Member

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    Well I think you need to get to know your bike a bit better - sometimes a throttle blip every now an again helps clear the throats. Give it enrichner, only as much as it needs, slowly reducing until you can move off, the odd blip here and there, and off you go. Maybe your synch and/or mixtures aren't quite right?
     
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