I have had a very similar problem to the member in this post http://gstwins.com/gsboard/index.php?topic=11149.0
I was riding my bike for about an hour on a hot day. All was going well until I was stopped at a red light for a very long period.
Whilst waiting there I noticed my idle was slowing to the point where the bike was about to stop. I gave a quick rev of the bike and she sprung back into life but then proceeded to drop revs to the point that she would stall.
The only way I could keep the bike going was to keep its revs at 3000rpm or above.
When I stopped the bike I noticed fuel dripping out of my air filter.
I wont bore you with all the details of my dangerous ride home, but it was scary with the bike well down on power and surging and spluttering quite dangerously. Still if I let the bike idle she wanted to stall. If she stalled the procedure to start her was similar to what you have to do tto start a flooded engine. Wide open throttle when you cranked her.
Now after a quick read on here I decided to check my float heights.
Sheet! They are non existent on both sides!!!
The fuel will keep flowing right on out of the carbs.
So I pulled the float bowls off and checked the float needles. They were both shmick! Not grit and still has a perfect cone point.
I bent the float tab so it would close the valve earlier then tried pouring fuel down the fuel line again. Still it comes out of both sides carbs!!!
I repulled the bowls, and tested the float needle by ever so very very lightly pushing it into its recess and then adding fuel to the fuel lines. It seals perfectly!!!
:dunno_white: Now I'm really at a loss. Why would both carbs develop this problem simultaneously and why hasn't adjusting the float tab made any difference what so ever?
Help!
Basically this is where I think I have a fuel problem
(http://img252.imageshack.us/img252/5292/fuelleaksuu1.jpg)
When I pour fuel into the fuel hose, after filling the float bowls it then runs out of these little holes at the bottom of the carburettor air intake.
This is what I have done so far to try and fix the problem
(http://img138.imageshack.us/img138/6777/carbfloatdw9.jpg)
Bent the float tab up and tightened the screw that holds the float valve seat.
Also cleaned all the jets and the float bowl (though they all looked brand new and no blockages to be seen)
The float needle still looks brand new!
(http://img139.imageshack.us/img139/4114/floatneedleyh8.jpg)
Here's a pic of the carbs with the float removed.
(http://img171.imageshack.us/img171/7323/carbnofloatwh4.jpg)
Could the float valve seat be the problem?
Can it be easily removed?
Is there an O-ring there that could be stuffed?
Any suggestions or advice would be hugely appreciated.
The fact both carbs seem to have the same problem is what is really perplexing me. What are the odds they both got the same problem simultaneously???
Is there something else I am over looking?
You may have a seat O ring issue ... the 01 and later carbs are very hard to bend the float tangs on. I'd just leave them be and figure out by blowing with your mouth into the gas line and seeing where its comming from.
Cool.
Srinath.
So can the float seat just be pulled out after removing the single screw?
Is it held in place by an O-ring?
because atm I can't see an O-ring anywhere :icon_lol:
Is your Floats full of Gas? if they develop a leak and Fill with gas they won't float enough to Close the Needle.I may just be the way the Picture looks but the Lower Side of those Floats look a Little Darker than the Back Sides. :icon_confused:
Yep, his floats look like they have fluid in them; there must be a hole or crack along the seam that lets gas in and they wont float and close the needle and seat.
Galahs - can you verify this?
They didn't feel like there was fuel in them, but I will rule that out as a possibility today. :thumb:
Take them Out and Shake them if you feel and Hear Gas Sloshing Around toss them and Buy new Floats.I've Always had a bad Feeling about Plastic Floats and Vibration after they Turn Dark and Harden.With Brass Floats they were easily Fixable.With Plastic ones you may be able to fix them Temorarily with Epoxy but I wouldn't trust them too far.
Unfortunately I've removed the floats and they are empty. I submerged them in fuel and they don't seem to be any air bubbles coming from it to indicate a leak.
personally I think the floats are a crap design! Rotate them on their pivot point and you notice the movement the tab places on the float needle is minimal.
I also tried turning the carbs upside down and blowing down the fuel line. Seems to be a perfect seal. Si its obvious the floats are not pushing enough pressure up on the float needle. Why I wonder?
Could the floats have gotten heavier with age? (They're only just over a year old!!!)
another thought.... could it be possible that the fuel I am using is less dense therefor why both carbs floats to not seem to be raising high enough to seal :dunno_white:
I filled up the day before the problems happened. Rode 20km home mostly doing highway speeds.
Then the next day rode for 45 minutes on the motoway (6000 rpm might have hidden the problem) Then it showed its head when I got into town in the stop start driving.)
Considering both carbs are leaking and both carbs are basically independent but share the same fuel supply... could I be on something?
I'm going to try some different furl right now.
Hmmmm thats Funny it's Possible that you may have got a BIG slug of Ethanol that had settled out of the Gas at the Station but I would say the Floats would Float just as much in alcohol as they would in Gas.You could Experiment with Rubbing alcohol and then gas to see if there is a Difference.I wouldn't think that the would be since Alcohol is Burned straight in some race Bikes,Quads ETC. and I've never Heard of Floats Sinking. :icon_confused:
Ahhhhhhhhhh! >:(
different fuel and it still flows out of the carbs like a tap!
Both sides just wont seal!!! :mad:
From the link I posted in the first thread...
Quote
Diagnosis : not sure.. but the mech tightened the carb values ? - if you look at this diagram :
<<<old link>>>
it's screw #13. He said that they were tightened to spec before, but tightened them a bit more (still in spec). He gave me a couple of pointers where to look if it happens again.
I can only see one screw in the carb but I don't know how that could make a difference.
Now if I manually push the float up ever so gently, it is at this position (it can go much higher) that the float needle seals perfectly.
ie. I can't blow through the fuel line.
(http://img145.imageshack.us/img145/8080/floatclosediq1.jpg)
So if the float does indeed float it should seal.
So maybe my float doesn't float enough anymore :dunno_white: but it doesn't have any fuel in it and I have submerged it in fuel looking for leaks and found none.
Arghhhhhh!!
And I just looked it up to find a single replacement float costs $20 US. What a rip off! (and a fair chunk of cash for something that may not be the problem)
Have you had a careful look around the area where the float pivots and is it free on the pin? Look for cracks or distortion in the plastic and the metal carb` body. Could something be physicaly limiting the floats travel and preventing it from moving the valve into position? It might be free to move by hand but will probably act differently when fuel is in the bowl.
Yeah it all looks good but tomorrow I'll have another look. Again I find it strange that both floats seemed to go at the same time.
Wonder if the heat of the hot day, plus idling for a long period did something?
[45
Thinking about it I had a similar thing happen on the GS a few years ago, it was a particularly hot day and I had just tanked up. I left the bike idling on the drive for a few mins for whatever reason when I got home and found it had dumped some fuel when I returned to it, it ran rough for a few secs but cleared itself. It never did it again so I forgot about it until now
We know fuel expands when hot and you are in an area with a high ambient temperature, maybe fuel somewhere in the circuit is becoming pressurised due to the effects of the heat and resultant expansion and it is just "blowing out" the overflow. Perhaps a lot of sun on the tank is enough to cause it. I would have a close look at the filler-cap and check the vents are not blocked, also under the tank at all the pipework making sure nothing is blocked or kinked.
I had the thought that it might have been caused by vapour lock or something when it first happened but now that I have disassembled the bike the fuel I'm pouring in is not hot, the engine isn't even running and the carbs still overflow just by pouring fuel into the fuel line.
I have also checked both float heights using the clear tube method and the float level is high... as high as the overflow pipe in the carb mouth.
The floats seem to rotate easily/freely/smoothly on their shaft so I can't see that hindering their movement. And the float needle valve seals correctly it I gently raise the floats (float bowl off)
Just once I put the float bowl bak on and pour fuel into the fuel hose it continues to fill up the float bowl until it starts flowing out the over flow.
So for some reason my floats (I'm having the same problem on both carbs) is not pushing the needle valve high enough to seal the inlet and preventing the bowls from flooding.
I've had a similar thing that happened to sledge, happen 20 years ago on a black bike that I once owned - filled up on a hot day, and as soon as I hung up the pump nozzle, I turned around and the gas was overflowing out the filler neck all over the tank!
Galahs - two tings:
1. With the floats installed, but without the floatbowls, turn the carbs sideways with the floats away from you, hold them about waist high so you can look across both carbs, lining up the floatbowl surfaces. Slowly rotate the carbs toward you (maintaining the alignment with your eyes (like you're shooting)), and observe when the float closest to you stops moving, apying special attention to where the needle stops, too. This is where it actually stops when fuel is in there.
Now you stated the the fuel level is as high as the overflow pipe in the carb mouth, that's your problem.
2. Pull the floats and put them in a bowl of gas for about a fifteen minutes to half an hour. If they sink, or take in gas, you'll know that's the problem.
Quote from: Jughead on March 17, 2007, 09:01:41 PM
Take them Out and Shake them if you feel and Hear Gas Sloshing Around toss them and Buy new Floats.I've Always had a bad Feeling about Plastic Floats and Vibration after they Turn Dark and Harden.With Brass Floats they were easily Fixable.With Plastic ones you may be able to fix them Temorarily with Epoxy but I wouldn't trust them too far.
phew. that was the LONGEST title i ever read.
I fixed it!
I'll write up a detailed explanation a little later. But thanks for the help GSr's.
You wont believe how easy the problem was to fix!!!
This has frustrated me for a while so I'll share the pain and tell the full procedure I undertook to make my realisation.
I knew my floats sealed ok when manually lifted so I decided to find out why my floats weren't floating.
They didn't have a leak and their was no fuel in them.
So I removed the float bowls but left the floats attached to the carbs,
I then filled the float bowls with methylated spirits, and raised them towards the floats whilst peering over the top of the bowl to see f the floats were infact rising. They weren't!!!
Hmmm, so my floats don't seem to float.
So I removed the float and put them in a container of metho. They floated!
Hmmm, I then submerged the float bowl in my ccontainer of metho so it was slightly submerged, then put the float in the float bowl. It floated!!!
So it seems that the float needs a bowl level just a touch higher than the float gasket to get it to float.
When I emptied the float bowl I thought it was strange that the float bowl seemed to hold more fluid than I had noticed when I drained the floats all these times when checking the level.
BINGO!!!
Something was stopping the floats from filling up enough, preventing the floats from rising. But how could this happen because the fuel is obviously rising up and out of the carb throat.
Wait a second!!!
What if there is an air lock in the float bowl!!!
No way.. it couldn't be!
I then decided to blow down the carb breather pipe.
Ahhhhhhhhhhhhhhhhh! It was blocked!
This would explain it. Both carbs shared the same breather explaining why both sides failed together.
So I removed the breather hose and blow down the breather connection and it flowed.
It ended up the breather pipe had a wasp build a mud nest in it!!!! blocking it.
I cleared the blockage, reinstalled the floats, float bowl for the 1 millionth time then tried pouring fuel down the fuel line.
NO LEAKS!!!!
Ahhhhhhhhhhhhhhhhhh! :mad: :laugh:
Everything solved!!!
So a simple breather blockage caused all my dramas and was nearly at fault for my death on the road.
I've done a drawing to help people understand what happened for future reference because I don't want anyone going through this heartache. We all take from GStwins and its good if we an all give alittle too!
Here is a diagram explaining what was happening.
(http://img296.imageshack.us/img296/8602/vapourlockeb2.gif)
The blockage of the breather hose prevented air from escaping from the float bowl as fuel was poured in.
As fuel entered the bowl, the bowl would fill pushing the displaced air out of the jets.
once the fuel level in the bowl reaches the jet no more air can escape from the float bowl. The pressure of the fuel flowing into the bowl however pushes the fuel up the jet into the carburettor throat, then leaks out the air filter.
The current level of the fuel is not high enough to allow the float to rise and shut the fuel supply off.
So fuel just keeps pouring into the float bowl, out of the jets, into the carb throat and out of the air box never allowing the float bowl to fill sufficiently.
After the vapour lock (air bubble) is cleared by clearing the breather, the fuel is allowed to fill the float bowl to a suitable level where the float will rise and shut off the fuel flow.
Here is a picture of breather hose I had to remove and clear a blockage from.
(http://img141.imageshack.us/img141/3503/carbbreatherdg6.jpg)
Great documentation! :bowdown:
Thanks for sharing!!!! I followed the thread completely clueless... congratulations for your findings :cheers: :cheers:
As Wrecent_Wryder stated, it was going to be some thing simple.
That makes it more frustrating!
It comes back to the old saying, check the simple things first!
And yeah, I put a little bit of effort in my findings to help my fellow GSers who I've learnt so much from :thumb:
T7
Quote
the lack of venting caused pressure in the bowls to build up beyond ambient, so fuel was jetting into the carbs even though the fuel level in the bowls never rose far enough to close the needle valves, is that it?
Yep! Exactly!
My carb breather hose runs to the rear brake side of the engine. I was thinking of putting a filter on it too to prevent this from happening again. For the time being a drilled a few holes in the rubber tube about 2 inches and 4 inches from the exit to make it harder to totally block the pipe.
Galahs,
I can't believe you solved this problem!!! I've been dealing with the exact same thing for over a year now and have tried all the same tests as you. My temporary solution has been to install a fuel shutoff valve so I wouldn't empty the tank thru the airbox every time I parked.
I can't wait to get home and check the carb breather hose... BRILLIANT!!!!
Jake :thumb:
Aaah, I thought I was gonna have a chance to feel so smart. I once had the same thing happening after dissassembling my carbs. The problem was that I went a little too crazy with the vacuum port caps I bought to replace the cracked ones. I didn't have a breather tube installed so I saw the open port for the breather and decided to cap that too. Gas was everywhere.
Then I read on and saw galahs tried this already and it was the magic fix. Glad its working now.
Damn mjn12, I wish you logged on a few days earlier, you would have saved me many heart aches!!! :laugh:
Would you believe I started my bike today and it was struggling to idle.
I straight away checked the breather pipe and it was full of mud!!!
I cleared the mud and shook the hose and a hole bunch (around 15) dead spiders fell out.
Seems we have a local mud wasp that thinks my bikes breather tube is a good place to store the prey he catches.
This made me think I better check my battery breather hose. It was completely blocked with mud and dead spiders too!!!
Ahhhh! Now I'm going to have to put some sort of screen or filter on my breather pipes.
this is very interesting my bike has the same issues im definatley going to try this tommorow
I'm also super glad this came back up! I am rebuilding my carbs in the morning due to mine pouring gas out of the left carb. I'll check this aswell. What I need is a good picture of how/where to messure the float hight. Anyone have one by chance? i need from where at on the float to where at on the carb body.
Toole
So glad this thread was here. I have been struggling to diagnose my leaking left carb, ever since I dropped the bike in the driveway last week. I took off the tank, pulled the airbox, checked all fuel line connections. Everything looked fine. Put it all back together but the carb is still leaking. Gonna check several items mentioned in your ordeal. Could be I buggered the float's functioning when the bike fell over on it's left side. Thanks for your detailed account. It gives me hope.
I'm having a similar problem, I hope this will be quick fix. If a wasp in my breather hose is the biggest issue I have, I"ll gladly evict the fellow and be on my way :D
Floats are simple, make sure they float first, if they do than you most likely need to clean the sealing surface and adjust
Sent from my iPhone using Tapatalk
I missed the rest of the thread sorry nvm my response
Sent from my iPhone using Tapatalk
THIS is a PERFECT example of the power and usefulness of online forums.
A a 7 YEAR OLD THREAD can, and is, still helping people solve their problems.
Short version; my project bike had this EXACT same issue....and it was after reading this that I found out it had the EXACT same problem as well.
See... the internet is good for other things besides porn. :woohoo: