Hello!
I did a search and came across this thread:
http://gstwins.com/gsboard/index.php?topic=13070.0
which seems similar to my problem, but I wanted some second opinions.
I was doing the standard things you do when you get a used vehicle/bike (oil/filter change, spark plug change [found champion spark plugs... replaced with NGK], air filter, drain and de-rust the gas tank as best I could, etc) when I noticed I have a fuel leak. I dont notice it when I'm driving and look down at a stoplight, but I've been able to re-create the problem when the bike is still. Here's what I noticed.
1) when I drive up to my parking spot and go over a lot of bumps which makes the bike rock, I have the leak
2) when the bike is on the center stand, motor off, I rocked the bike back and forth. No leak (perhaps where the leak comes from was out of fuel?). So I switch to PRI, wait a second, and rock the bike 5 or 6 times. I get a leak coming down the idle adjustment screw.
I havent had the carbs off, so I havent been able yet to double check any hoses on the underside of the carbs. When I first noticed a fuel leak problem, I could have sworn I also had some in the bottom of the air box, which from searching tells me the float valves may need replacing? I dont remember I was looking through so many threads I think I got a bunch of stuff confused.
Im leaning toward some kind of gasket/ring leak.
Anyway, if anyone has an opinion on what the problem is, or what I should check to narrow things down, Id appreciate it.
Cheers!
i'll bet on your float heights and / or your float needles being bad. either is an easy fix. heights have pictures here on the forum. float needles are a few dollars to replace.
there is a T connector between the carbs that gets old and cruddy over time. actually two of them. one is a vent, one is a feed. check them for cruddiness and replace if needed.
have you replaced your fuel lines yet ? didn't notice if you had in the original post.
the o-rings may be shot too, but you'll find out when you get the carb float bowls off n stuff.
welcome :)
Thanks for the reply, and thanks for the welcome! :)
I'll probably be jammed up this week, but I'll try to find the time to take the tank off (again, heh) and check those lines for crud. It wouldnt suprise me if they were dirty.
I havent replaced any of the fuel lines yet. They seemed to be in reasonable condition. No cracks or tears and they seemed very flexible and pliable as opposed to being brittle.
Is there a vendor or someone I should use that supports the site, or just go to the dealership or ebay for parts?
Well today the bike decided it was going to have a hanging idle and not stay on idle. I would set the idle screw at one point and it would hang at 3000rpm, so I would turn it down to where it would sit at 1500 but after a few seconds it would start to dip and eventually die.
I think the carbs have to come off and have a good cleaning. Now that the tank has been cleaned out as best as I could I think there is some residual junk that made its way into the carbs.
As for the leaking fuel, I noticed that the fuller the tank, the more of a propensity it has to leak fuel. Moreover, I had the tank off again to check lines and I noticed that the upper T has no hose that goes over the airbox. The diagrams I found say its the overflow. Instead of a hose I found the T pointing straight down.
Is it possible that the slight rise in the fuel overflow line that is supposed to be there "traps" fuel until it can be burned? Based on the way it leaks out, it seems like this T is the culprit for my leak.
Thanks in advance for any advice to make do until the weekend when I can clean the carbs out.
Quote from: CanukGS500 on September 02, 2008, 05:14:49 PM
Well today the bike decided it was going to have a hanging idle and not stay on idle. 1) I would set the idle screw at one point and it would hang at 3000rpm, so I would 2) turn it down to where it would sit at 1500 but after a few seconds it would start to dip and eventually die.
3) I think the carbs have to come off and have a good cleaning. Now that the tank has been cleaned out as best as I could I think there is some residual junk that made its way into the carbs.
As for the leaking fuel, I noticed that the fuller the tank, the more of a propensity it has to leak fuel. Moreover, I had the tank off again to check lines and I noticed that the upper T has no hose that goes over the airbox. The diagrams I found say its the overflow. Instead of a hose I found the T pointing straight down.
4) Is it possible that the slight rise in the fuel overflow line that is supposed to be there "traps" fuel until it can be burned? 5) Based on the way it leaks out, it seems like this T is the culprit for my leak.
Thanks in advance for any advice to make do until the weekend when I can clean the carbs out.
1) sounds like a vacuum leak (check your vacuum caps and the petcock line) causing high idle (lean mixture)
2) lean mixture, possible fuel starvation afterwards ?
3) well, if you want to sure. more than likely those float needles are pitted (in the rubber) or the float height is set wrong
4) nah, that over flow is only for When Things Go Wrong With Fueling and it vents to the atmosphere
5) the T is only the escape route, the culprit lurks inside ;)
someone will post the stuff I missed in 3, 2, 1...
:)
well whats weird is that this didnt start happening until today on my way home from work. I wonder if I didnt get everything out of the tank when I rinsed it from doing the de-rust and some of it got in the carbs. If its running lean then I'm kind of worried because its my daily and im paranoid about driving it now.
I checked the lines and they seemed tight with no leaks, and the vacum caps (what I think is the "top cap" in the service manual) is also nice and tight. I guess the next step is to hit an auto parts store and buy all new fuel lines and plumb them up to make sure there are no foreign bodies in any of the lines.
Could a faulty diaphram be a culprit as well?
Quote from: CanukGS500 on September 02, 2008, 06:03:13 PM
well whats weird is that this didnt start happening until today on my way home from work. I wonder if I didnt get everything out of the tank when I rinsed it from doing the de-rust and some of it got in the carbs. If its running lean then I'm kind of worried because its my daily and im paranoid about driving it now.
I checked the lines and they seemed tight with no leaks, and the vacum caps (what I think is the "top cap" in the service manual) is also nice and tight. I guess the next step is to hit an auto parts store and buy all new fuel lines and plumb them up to make sure there are no foreign bodies in any of the lines.
Could a faulty diaphram be a culprit as well?
yes.
also, shaking up all the stuff in the tank may have put some trash in the pilot jets. mine has some trash in them actually, as -just- off idle response is getting a little ugly.
time for me to pull the air cleaner, freshen it (K&N), and dump my float bowls too. :)
well Im still going to give the carbs a good once over, but i think I found the problem with the idle, and im such a n00b im embarrased to tell what happened.
Yesterday morning as I was pulling the cable off the bike, I had a lack of coffee moment and tipped the bike over. Fortunately a couple of plastic trash cans gave their lives so that my bike would be spared scratches :)
So after taking it to the stealership to have the rear tire put on and the bike inspected (just got the bike) on the way home is when the erratic idle popped up.
It was acting this way this morning as well, especially once the bike warmed up. When I got to work and stopped the bike, I went to turn it back on and it wouldnt even start! no clicks, no turning, nothing (all lights and the like worked though). Thats when I noticed the big red switch by my right thumb....
... yep, you got it, the switch was cocked half-out of the "on" position.
I smacked it firmly in "On", started the bike, and the bike kept a nice healthy stable idle.
who woulda thought?
Im still giving the carbs an overhaul though. Given what came out of my gas tank and the age of the bike it definately wouldnt hurt to give them a good cleaning especially because this doesn't solve the fuel overflow problem..
Thanks for all the advice and help! Very much appreciated!
I lied... the lean problem is still there.
I took off the top part of the carb and sprayed some carb cleaner down where the needle jet goes. I felt something unstick and it briefly ran great after I did this. HOwever, shortly into my ride, the weird problems came back.
I also noticed one of my needle jets (the needle under the spring and diaphram) is slightly bent. Im wondering if this could have been part of the problem too.
Anyway, im ordering new needles and I'm going to put them in and clean everything. Hopefully that will be the end of my carb troubles.
cleaned out the carbs but now I have a pinhole leak in the gastank which I just fixed.
what a day :(
Quote from: CanukGS500 on September 03, 2008, 05:18:23 PM
cleaned out the carbs but now I have a pinhole leak in the gastank which I just fixed.
what a day :(
Well, that could very well explain your initial problem. How did you fix this? The only ways to really do it right are either re-welding the seam or using an epoxy coating on the interior. If you tried to JB weld it it will probably end up leaking again.
I used an epoxy that is designed for fuel tanks to fix the leak. So far, so good. The stuff claims to be permanent