Over revving at random

[voughtcorsair]

Good morning,

Just picked up my '02 GS500 a week ago and she's been having nothing but problems. At first, she wouldn't start (charged battery) then would stall almost immediately at idle (cleaned carbs, put floats as high as possible,) and now it over-revs at random - talking a random climb to 6-7k RPM in first/second gear without touching the throttle. Idles really high (hangs?) and then will slowly come down in RPM. Seems like some kind of leak. Ordered new gaskets for the bowl since those were disintegrating & today will be readjusting throttle cable and setting floats to 14mm. Any other things to check on if those ideas don't work? I just wanna ride this thing before it gets too cold! Thanks in advance for any help

[Armandorf]

review last topics,check vaccum leak,oring intake boots,carb  float height/float valve and cylinder head valve gap, check exhaust is not loose, inspect spark plugs,clean tank/put inline filter,inspect petcock

[karlhoffman_76]

Good morning,

Just picked up my '02 GS500 a week ago and she's been having nothing but problems. At first, she wouldn't start (charged battery) then would stall almost immediately at idle (cleaned carbs, put floats as high as possible,) and now it over-revs at random - talking a random climb to 6-7k RPM in first/second gear without touching the throttle. Idles really high (hangs?) and then will slowly come down in RPM. Seems like some kind of leak. Ordered new gaskets for the bowl since those were disintegrating & today will be readjusting throttle cable and setting floats to 14mm. Any other things to check on if those ideas don't work? I just wanna ride this thing before it gets too cold! Thanks in advance for any help

What do you mean by "put floats as high as possible"? Your float adjustment should be to a factory specified level. You even mention that a bit later.

[voughtcorsair]

What do you mean by "put floats as high as possible"? Your float adjustment should be to a factory specified level. You even mention that a bit later.

Karl, a friend helped fix the initial non-starting problem and just stuck em way up there to the top since he'd had a similar problem and raising the floats had fixed it. Right now my goal is to just get the bike back to factory settings since I know that in theory there's fuel/air/spark

[karlhoffman_76]

Karl, a friend helped fix the initial non-starting problem and just stuck em way up there to the top since he'd had a similar problem and raising the floats had fixed it. Right now my goal is to just get the bike back to factory settings since I know that in theory there's fuel/air/spark

Easy mate, let us know how it goes. It's possible setting your floats appropriately will be the fix.

[Joeywhogs500]

I've been trying to post but idk how to I'm new here and it brought me here.  Has anyone used the first generation carbs of the gs500 on a newer model (2009 gs500) if so is the stock jets(37.5/122.5) good or do they have to be changed to a different size?

[voughtcorsair]

Easy mate, let us know how it goes. It's possible setting your floats appropriately will be the fix.

Well, I put everything back (after literally a month  ) and she doesn't run. It cranks GREAT since I stuck a new battery in but won't even give a hint of starting. I might've hooked everything up wrong (though I doubt it, I'm new to working on bikes so it totally could've been my bad), I'm gonna check the idle screw...maybe that's the last problem to fix? We definitely messed with it after the over-revving fiasco. I'd be surprised if that's it, but...oh well. If that doesn't work I'll start checking compressions, etc., I have no idea at this point, it seems like for every thing I fix/clean up, something new pops up. At this point, I just need it to run for a six-minute drive to my buddy's garage before it snows...

[karlhoffman_76]

Well, I put everything back (after literally a month  ) and she doesn't run. It cranks GREAT since I stuck a new battery in but won't even give a hint of starting. I might've hooked everything up wrong (though I doubt it, I'm new to working on bikes so it totally could've been my bad), I'm gonna check the idle screw...maybe that's the last problem to fix? We definitely messed with it after the over-revving fiasco. I'd be surprised if that's it, but...oh well. If that doesn't work I'll start checking compressions, etc., I have no idea at this point, it seems like for every thing I fix/clean up, something new pops up. At this point, I just need it to run for a six-minute drive to my buddy's garage before it snows...

Did you remember to open the tank petcock with a flathead screwdriver when putting the tank back on? If so, did you prime your carbs with fuel before setting the external petcock to "on"? Is the vacuum line for the diaphragm connected?

[voughtcorsair]

Did you remember to open the tank petcock with a flathead screwdriver when putting the tank back on? If so, did you prime your carbs with fuel before setting the external petcock to "on"? Is the vacuum line for the diaphragm connected?

The fuel petcock on the tank is on, as is the external one. I connected the little line running from the petcock to the brass nipple, which I'm pretty sure is correct...but I'm not sure about priming the carbs? I tried starting it with the external petcock on all the different settings including prime. Not sure if that's right though...

[voughtcorsair]

Did you remember to open the tank petcock with a flathead screwdriver when putting the tank back on? If so, did you prime your carbs with fuel before setting the external petcock to "on"? Is the vacuum line for the diaphragm connected?

Ok, so...primed the carburetor, f%&ked around with the idle screw and set it lower, then let her warm up real good and she's good to go. The over-revving happens only with the choke on now which I think is honestly fine and everything seems to be sorted.

For anyone reading the thread and having the same issue, I cleaned the carbs, replaced the gaskets on the bowl, eyeballed a 14mm float height, and have the idle set to 1300ish and baby it while it warms up. She seems to want to run for 2-3 minutes or so before starting to turn the choke off. I also primed the carburetors by holding down the starter button (not touching anything else, it shouldn't turn over, I think this just turns the gas on?)

Since it's running good tonight, I brought her to her new home in my buddy's garage instead of at the town dock lol.

[karlhoffman_76]

Ok, so...primed the carburetor, f%&ked around with the idle screw and set it lower, then let her warm up real good and she's good to go. The over-revving happens only with the choke on now which I think is honestly fine and everything seems to be sorted.

For anyone reading the thread and having the same issue, I cleaned the carbs, replaced the gaskets on the bowl, eyeballed a 14mm float height, and have the idle set to 1300ish and baby it while it warms up. She seems to want to run for 2-3 minutes or so before starting to turn the choke off. I also primed the carburetors by holding down the starter button (not touching anything else, it shouldn't turn over, I think this just turns the gas on?)

Since it's running good tonight, I brought her to her new home in my buddy's garage instead of at the town dock lol.

To prime the carbs, you set the external petcock to the "PRI" position, which bypasses the vacuum operated diaphragm. Gravity will automatically feed fuel into the float bowls, you just have to wait a few minutes to ensure they are full.

Over-revving with the choke on is normal, it will do that. For future reference, the operator's manual for the GS recommends choke on for 30s held at 3k rpm on start up, you theoretically shouldn't need it on for longer than that, but that could depend on the environment you're operating in. For temperate climates, such as where I live, 30s @ 3k rpm is enough to hold the min revs on start and then about 5-10 min of riding to get up to full operating temperature and nominal revs.

What did you set your pilot screws to btw? Are you using the stock airbox and exhaust? Do you have stock jets?