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Low RPMS with choke

Discussion in 'XJ Technical Chat' started by Glen F., Sep 28, 2021.

  1. Glen F.

    Glen F. Active Member

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    Not sure what to make of this, but when I start the bike with the choke on, it doesn't get to around 2000 rpms. It sits just above the regular idle. After the bike warms up and the choke is off, it runs just fine. I've synced, color tuned, and synced again. The bike runs fantastic, but takes a bit to warm up with low RPMS. Any idea why I can't get the 2000 RPM's at start up, that it should be at with the choke on?
     
  2. jayrodoh

    jayrodoh YimYam Premium Member

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    Is this your 82 Maxin 650? I would suspect that the enrichment circuit is plugged up somewhere in one or more carbs, the "choke" is ineffective if plugged up. Does it start okay? If it starts okay and just takes a little longer to warm up, I probably wouldn't worry about it. Save that job for winter.
     
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  3. Glen F.

    Glen F. Active Member

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    Yes it's my 82 xj650. That's the strange part, it starts fine with a flip the the throttle. It's not the end of the world, but strange that it would all of a sudden happen.
     
  4. Minimutly

    Minimutly Well-Known Member

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    Strange that all faults are "strange, weird, all of a sudden".
    As @jayrodoh says, likely one or more enrichment "well" is blocked. Someone explained this quite well the other day - the well fills over time (so not fully blocked), but once the engine is running the level in it drops, so any "choke" action is reduced from then on.
    You could pull both the outer bowls off (90 degree screwdriver attachment) to check them, might tell a story?
     
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  5. Jetfixer

    Jetfixer Well-Known Member

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    The best thing to do is pull carbs , remove float bowls , and spray nozzle in carb cleaner both directions ( aim away from yourself, it will shoot a jet if it is clear) and a piece of .020 safety wire . Please note , the jet is staked in. Use a strong light you should be able to see the opening in bottom of the bowl.
     
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  6. Glen F.

    Glen F. Active Member

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    I pulled them yesterday, sprayed carb cleaner in all bowls and blew them out with compressed air. The flow is good through the holes. No change at start up. I stand by the bike and hold the throttle so it's at 2000 until it warms up.
     
  7. Glen F.

    Glen F. Active Member

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    Started the bike this morning and the rpms were at 2000. First time in days. Had a small issue when starting though, and it's not the first time. Starter button didn't work right away. I know I have to get in and clean that up. It did start but, something sounded like it was arcing from the engine. No smell of smoke nor could I see any in the dark.
     
  8. XJ550H

    XJ550H Well-Known Member Premium Member

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    clean the battery termanil and stareer cable on the solinoid too
     
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  9. Minimutly

    Minimutly Well-Known Member

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    Starter brushes?
     
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  10. Glen F.

    Glen F. Active Member

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    Checked and cleaned all connections, not that they needed it. I haven't heard that noise since it happened.
     
  11. Glen F.

    Glen F. Active Member

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    Very little time right now because it's crazy at work. I'll pull the starter when things slow down. What am I looking for? I've never done this before.
     
  12. XJ550H

    XJ550H Well-Known Member Premium Member

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    crud filth short brushes .
    if you are going through the trouble of pulling and opening the starter you should consider replacing the brushes at minimum ..
     
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