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Thread: GS550 has no high RPMs

  1. #1

    GS550 has no high RPMs

    I recently bought a 1981 Suzuki GS 550 as a bike for my son and me (I'm just starting riding). The bike was in good shape and runs well except that it will not rev above about 7K RPM. Any experience with this? The parts are all stock; he thinks its running lean and essentially runs out of gas.

  2. #2
    RiderCoach 8000 Posts! WoodstockJeff's Avatar
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    Lots of possibilities. Clogged fuel strainer, pinched fuel line, dirty carbs, for starters. Even a rats nest in the air box.

    Sat for a while?
    Jeff

    "The future is so much easier to predict when you have a handle on how you arrived at now.... Works with traffic just as well as the rest of life. "

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    Flirting With The Redline 1000 Posts! ZaGhost's Avatar
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    I'd start with the carbs, Performance for the 80's bikes begins with good clean carbs.
    Running lean wouldn't give you that effect, it would accelerate nice and fast, run hot, but not an out of gas feel.
    Now incorrect float levels.... that would cause an out of gas feel if set too low
    Read the GS resources carb cleaning series ( mind you they go to an extreme, no need to split the rack usually as syncing them up afterwards is a real PITA)

    I has a similar issue with my Yamaha when I got it only to find the PO had reversed my main jets.
    Soooo it's possible a PO may have messed the order up. a Service manual will tell you the correct sizes and you can double check them while cleaning.
    The GS is a great bike, damn near bulletproof. a Little TLC and you got a winner

    Oh and be sure to check all that Jeff mentioned while your at it and I'll throw in dirty/missing air filter
    1999 SV650 (US import)
    1983 Yamaha Maxim 400
    My Maxim rebuild page

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    Flirting With The Redline 2000 Posts! Repeater's Avatar
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    A tank breather or fuel cap whose vent does not work anymore will also starve the engine of fuel enough to limit rpm, too. Otherwise, stuck carb floats are likely culprits as well.
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  5. #5
    Thanks for the replies above. I did order the manual (arriving next week). We'll check out all points suggested. In addition, I picked up an 82' CB 650, so I'll probably pick your various brains about that in due time. One bike at a time. I guess my pretty familiar quotes right now would be "When all else fails, read the instructions" and "If it ain't broke, don't fix it." Thanks.

  6. #6
    Flirting With The Redline 1000 Posts! ZaGhost's Avatar
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    If it ain't broke doesn't always apply to older bikes....... some fall into the " if it hasn't failed yet, it will" category
    Preventative maintenance can easily save your life in some cases
    1999 SV650 (US import)
    1983 Yamaha Maxim 400
    My Maxim rebuild page

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    Senior Moderator We've stopped counting... subvetSSN606's Avatar
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    All good suggestions and most likely either fuel flow or air flow. I believe that bike should redline at 10K.

    The only unlikely but possible thing not mentioned yet that comes to mind is too much slop in the throttle cable/linkage so that you're not really opening it up all the way.

    Tom
    In the end, regrets rarely come from things done, but from things not even tried.


  8. #8
    Hittin' The Twisties squirrelman's Avatar
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    Bike won't run to top rpms unless all cylinders are firing, so check headers for heat, and investigate if you find one stone cold.
    '66 YL-1, '72 CB125 , '89 VTR 250,'90 VTR 250, '89 NT650 Hawk, '86 VFR700(3), '86 Radian, '90 NT650, '97 VFR750.

    We're goin' to Hell in a bucket, but at least i'm enjoying the ride!"

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