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Discussion Starter #1
My wife has a Suzuki gs500f and it has an ongoing problem and nothing I do seems to change anything. Since the day we bought it, it has two spots on the tac that make a suction sound around the carb area. As you increase the revs, it starts around 1700rpm and then again around 2500rpm. The tack kind of bounces as it spits and pops and once past 2500rpm it seems to run fairly well. I'm not 100% sure its a sucking sound but that's what it sounds like to me. I did a carb cleaning...didn't change a thing. One of the diaphragms was smushed when we got the bike, replaced them with new ones...no improvement. Maybe I'll post a vid later of the tac and the sound. Any ideas? Any help would be greatly appreciated.
 

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My wife has a Suzuki gs500f and it has an ongoing problem and nothing I do seems to change anything. Since the day we bought it, it has two spots on the tac that make a suction sound around the carb area. As you increase the revs, it starts around 1700rpm and then again around 2500rpm. The tack kind of bounces as it spits and pops and once past 2500rpm it seems to run fairly well. I'm not 100% sure its a sucking sound but that's what it sounds like to me. I did a carb cleaning...didn't change a thing. One of the diaphragms was smushed when we got the bike, replaced them with new ones...no improvement. Maybe I'll post a vid later of the tac and the sound. Any ideas? Any help would be greatly appreciated.

Hey Strom... Clue me in. What year GS500? Has it been "altered"? Meaning, airbox removed, K&N air filters added? Perhaps a different muffler? Did it run great one day and suddenly develop a problem? Clue me in bro!!!
 

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Discussion Starter #3
Its a 2004, all stock 6,900 miles. Always had the problem but we were both still able to ride it we just had to feather it a bit to get moving. Once above the 2500rpm mark it rides like a dream. One thing new was last fall we got caught in a rain storm and it quit on her, so we switched bikes and I limped it out of the storm and once on dry roads it started to perk back up. Not sure if the two problems are related but I thought I would mention it. Won't let me upload a vid
 

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Kinda sounds like a possible vacuum leak problem. As you describe the problem, it is only happening at low rpms. As the rpms increase it (the problem) disappears... Is this an accurate discription?
 

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Yeah that sounds right. Would that effect the idle adjustment? I haven't messed with it for a long time (I gave up :biggrin:) but it idles a bit low and when I turn it up to where it sounds right we ended up sitting at stop signs and stop lights with it revving up at 4000rpm and it wouldn't go back down until we adjusted it to where it was before. Thanks for the input Jack! This vacuum leak... How would I go about finding something like that?
 

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I too think there is a vacuum leak somewhere. I remember the Honda VT500C I owned, had rubber boots that the Carbs mounted in to. If those are failing to keep a tight seal at the base of the Carb(s) I'd replace em.

You mentioned "feathering" at slow start up.........I had a lag at low speeds, when trying to accelerate quickly (say, getting on a highway from the entrance ramp) and added a couple of ignition washers to the Main Jets to allow more fuel in. Helped a bit with the lag.

-Soupy
 

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Yeah that sounds right. Would that effect the idle adjustment? I haven't messed with it for a long time (I gave up :biggrin:) but it idles a bit low and when I turn it up to where it sounds right we ended up sitting at stop signs and stop lights with it revving up at 4000rpm and it wouldn't go back down until we adjusted it to where it was before. Thanks for the input Jack! This vacuum leak... How would I go about finding something like that?
Yes, a vacuum leak would make maintaining a consistent idle difficult. Vacuum leaks tend to affect the engine more at lower rpms. I use a can of non-chlorinated carb cleaner (with a skinny straw attached) and start spraying the areas where the carbs attach to the engine, then where the air box attaches to the carbs, and any vacuum lines attached to the intake ports (such as the one that controls the fuel petcock valve). Start the bike, then start spraying and listen for a sudden change in idle. When the idle changes, that spot is the suspect.
 
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