Author Topic: 87 Fuel Leak/Dripping  (Read 851 times)

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Offline PapaFredrico

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87 Fuel Leak/Dripping
« on: April 29, 2018, 02:23:47 pm »
Hello all.  New to the group (and Concours) and amazed at how much of a community there is for this bike.

I just purchased an 87 used which came with an amazing compendium of information on the bike (including years of mint copies of magazines) as well as some OEM parts, etc.

The bike was out of gas when I test drove it, and the owner had me head straight to the gas station. I went there on the way home and put a couple gallons in.  Woke up the next morning and found it was dripping gas (about a drip a second) out of the inner drain tube from the bottom of the bike.  I moved it outdoors, and put something under it to catch the gas, and then attempted to put the bike on its center stand so I could investigate.  When I did that, gas splashed out and onto my hand from under the tank.

I realize I've bought a project and I don't care.  The bike is amazing and my ride home (despite being in hard freezing rain) was fun. 

Anyone have any ideas?  Based on reading the owner's manual (included - again amazing) the bike should electronically stop the flow of fuel on turning off the bike.  I believe this is a vacuum based system (based on reading these forums), and I suspect the inner workings of the petcock have failed (probably due to ethanol sitting in the system).  That being said, gas coming out from under the tank is terrifying and points to another issue altogether.

Thanks for any help! 

Chris

Offline Mettler1

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Re: 87 Fuel Leak/Dripping
« Reply #1 on: April 29, 2018, 02:48:56 pm »
   If you have gas coming out of a carb it usually means the float needle is stuck open and overflowing . Most likely dirt or rust in the float needle! Not good. Do NOT try to start until you find the problem. Even if the petcock is bad the carb needles should control the flow of gasoline.

  Watch videos     .https://sites.google.com/site/shoodabenengineering/video-resources

   Get acquainted with the danger of hydrolock!!!

           
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Offline Harry Martin

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Re: 87 Fuel Leak/Dripping
« Reply #2 on: April 29, 2018, 03:20:59 pm »
I've had the same issue on my 86 that was caused by pieces of the fuel line getting into the carb needles.
Only after replacing the fuel line did the problem go away. It happened while on a ride. Bike didn't lock up but it was wasting fuel like sieve.
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Offline DC Concours

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Re: 87 Fuel Leak/Dripping
« Reply #3 on: April 29, 2018, 03:39:41 pm »
What inner drain tube??? And splashed from where under the tank??? You have a rust hole there or damaged petcock?

These gas leaks are dangerous not just as fire hazards but are telltale signs of a future hydrolock.

Don't park your bike in your garage till this is resolved and do not start it either.

Offline connie_rider

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Re: 87 Fuel Leak/Dripping
« Reply #4 on: April 29, 2018, 06:51:11 pm »
Papa, a stock C-10 does not leak gas out of the carbs bowl drain port, (because it is sealed by the drain screw}
 Unless;
 1: The bike has had overflow pipes added to the float bowls. {Would normally have a hose attached to all 4 carbs}
 2; The drain screw is not properly seated.

We need more info to assist you??

Ride safe, Ted
 
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Offline PapaFredrico

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Re: 87 Fuel Leak/Dripping
« Reply #5 on: April 30, 2018, 01:21:42 am »
So in response to DC Concours:

There are two tubes that exit under the right side of my bike, one that is black and is closer to the outside, and one that is white (or clear) that is closer to the center of the bike.  The gas is dripping from the inside tube.

Regarding parking the bike indoors and starting it, that's affirmative - I had no plans to do either (totally familiar with the explosive qualities of gas vapors).

I haven't had much of a chance to work on the bike as now I'm outdoors, and I live in Oregon and our friend rain was here today.  It'll probably be Wednesday before I have some time to investigate further.

In response to connie_rider:

They call this thing a C-10?  Good to know. :)

1: I have no idea what modifications have been done.  I can tell you this - they weren't done by the original owner, he likely would have viewed that as sacrilege given the meticulous maintenance he performed on the bike.

2: Drain screw sounds interesting.  Reading the manual I did come across this in the section where it discussed using the 'Prime' setting on the petcock to drain the tank.  Perhaps this is just loose?  Would that cause this?

In response to Mettler1:

This is what I thought too.  Confused as to how fuel was getting through.  Like I said, I rode the bike (not knowing about the leak because the seller failed to disclose it) and it ran great.  A stuck carb would have made it run like crap, right?



Thanks for all your help everyone!

Offline connie_rider

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Re: 87 Fuel Leak/Dripping
« Reply #6 on: April 30, 2018, 01:36:16 am »
Papa, I (and probably most of the others) thought you were referring to the nipples on the bottom of the carbs.
Please look at the bottoms of the carbs and tell us if there is a hose (or hoses) attached to the nipples.
   (If there is, see where it goes)
I recall 2 lines under the right side of the bike.
(I think) 1 is from the overflow of the gas tank. The other is from the battery.

Ride safe, Ted
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Offline PapaFredrico

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Re: 87 Fuel Leak/Dripping
« Reply #7 on: April 30, 2018, 01:56:40 am »
So here's a picture of the two tubes.  The one with the pointer is where the gas was coming from.  I did check the battery compartment and there's a hole for drainage, but no tube running from there.  Also, there didn't appear to be gas in there (although it could have evaporated I guess).

Offline PapaFredrico

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Re: 87 Fuel Leak/Dripping
« Reply #8 on: April 30, 2018, 01:58:33 am »
And here's a picture from the other side.  You can see it's still a little wet from gas.


Offline connie_rider

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Re: 87 Fuel Leak/Dripping
« Reply #9 on: April 30, 2018, 02:14:18 am »
From the manual, there at 3 hoses on the right side.
   1 is the battery vent hose.
   2 is the tank vent hose.
   3 is the (tank) fuel gauge drain hose.

From where the gas is, I suspect a leak in the tank, or a leak in the diaphragm of the petcock.

Is there a hose attached to the bottom of the carbs??
Was the bike running and idling ok?

Ride safe, Ted
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Offline PapaFredrico

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Re: 87 Fuel Leak/Dripping
« Reply #10 on: April 30, 2018, 02:24:05 am »
This is going to sound dumb but I'm not sure where the bottom of the carbs is (I'm a student too, so doing homework more than YouTube videos right now).  I just ordered a Clymer manual from Amazon.

In my opinion there kind of has to be a leak in the tank given the gas that came out when I attempted to put the bike on its center stand.  I'm sure I'll find it as soon as I start pulling things apart.

That being said, the gas coming out of the overflow tube sounds like a different symptom altogether, and from the sound of it, likely a combination of a bad petcock and crap in the carbs.

The bike ran and idled great, that's the puzzle to me.  It started right up, no rough idle, and really, really smooth.  Reminded me of my 78 naked wing I used to ride.


Offline PapaFredrico

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Re: 87 Fuel Leak/Dripping
« Reply #11 on: April 30, 2018, 02:37:44 am »
Alright, watching Steve's videos, thanks Mettler1.

Offline connie_rider

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Re: 87 Fuel Leak/Dripping
« Reply #12 on: April 30, 2018, 02:04:48 pm »
Look thru the hole {below the tank/behind the cylinders} on either side of the bike.
You can easily see the bottom of all 4 carbs...

We are all hoping you don't have a stuck float in on of the carbs as that can lead to hydrolock. "BAD"

The fact that the gas you've seen is at the base of the tank, makes us think it's a leaking tank {or possibly a leaking petcock and the gas blew back while riding}.

The hoses you mentioned are not attached to the carbs, but one could have been added if the bike has stand pipes installed.

Wish someone was near you that owns a Connie..

Ride safe, Ted

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Offline Katsi

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Re: 87 Fuel Leak/Dripping
« Reply #13 on: April 30, 2018, 03:02:07 pm »
Whatever you do, don't try to start it until you get tot he bottom of the problem.   :-\

Offline PapaFredrico

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Re: 87 Fuel Leak/Dripping
« Reply #14 on: April 30, 2018, 04:27:45 pm »
Went out this morning (I had daylight now) and looked.  Easy to spot.  Who can't find carbs?  <-- This guy  ;)

Uncovered set of four nipples out for display.  The second one with a bead of fuel on it (the likely culprit).  I'm wondering now if that fuel that appeared to be dripping out of that tube was simply running down it.  That being said, the gas coming out when trying to centerstand the bike could point to it dripping from somewhere else.

I've watched several of Steve's videos now, totally terrified about hydrolock (how can you ever start your bike without being in mortal fear?).  Battery is disconnected, and I'll do the 'pull the plugs, cover, and prepare for the spray' technique (of course after I get the carbs cleaned).

Sounds like I should invest in a set of drainage tubes, right?  Anyone got pointers on a good set?

Thanks!


Offline JPD

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Re: 87 Fuel Leak/Dripping
« Reply #15 on: April 30, 2018, 04:57:14 pm »
I am repeating Sisf, put a hose on the bottom nipple of a carb, blow into it. If you can, it has overflow tubes installed. A good thing. If no airflow, no overflow tubes. Sisf is the go to guy for carb work. Tank valve rebuild is a DYI item. Gas tank will rust at left back corner and leak. Hose on right bottom of bike could leak if tank is overfilled cold and expanding fuel comes out vent to the cap area. Cap drain connects to one of the nipples at the back of the tank, view with seat off.

Offline PapaFredrico

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Re: 87 Fuel Leak/Dripping
« Reply #16 on: April 30, 2018, 05:31:49 pm »
Thanks JPD.  I'll get a hose and try blowing on it.  Out of curiosity, where will that send the fuel?  Out the tube?  If the carb is full of fuel (as it appears number 2 is) and I blow in with no overflow tube installed won't that send the fuel right into the cylinder (where I don't want it)?

There's no way this thing was overfilled.  It was bone dry and running on fumes (likely due to the leak) and I put 10 dollars in (about 2.7 gallons).  My understanding is this thing has a mammoth tank.




Offline connie_rider

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Re: 87 Fuel Leak/Dripping
« Reply #17 on: April 30, 2018, 06:50:05 pm »
I've watched several of Steve's videos now, totally terrified about hydrolock (how can you ever start your bike without being in mortal fear?). 

Installing stand (overflow)  pipes in the carbs will "absolutely" prevent hydrolock.

Sounds like I should invest in a set of drainage tubes, right?  Anyone got pointers on a good set?

Part of Steve's carb rebuild includes installation of standpipes.


  Do not do anything until you discover where your fuel leak's are.
Luckily you say the bike is running good, so this may save you a little initial effort.

Tank/petcock leak:
  Remove the tank and look it over. (We can instruct you on how to do removals).
  If the tank or petcock is leaking, everything below it can have gas on it.
  Also, if the tank is leaking it is probably from corrosion, and you need to fix that before moving on to carbs.
  On the side of the petcock is a small hole. Turn the petcock to prime and see if gas leaks out of it.
   If gas is coming out of that hole, the diaphragm in the petcock is torn.
    {Do not leave the petcock on prime when your finished}.

Even if it's ok, I recommend buying a kit and rebuild the petcock while you have tank off.
 Murph has 1 that will do for now...

Carb leak;
  A standpipe in a carb can leak slightly if the fuel level setting is high or if the needle has a bit of trash on it.
  So find out why it is leaking.. May be a simple fix...

  Your blow test will establish if you already have stand pipes.
     If you do have them, great!!
     A carb flush might do the trick for now...

  If you don't have them, try removing, cleaning the tip, and reinstalling the carb drain screw.
     If that solves the problem I still recommend stand pipes, but it gives you time to learn your bike.
      Eventually "DO" INSTALL STAND PIPE'S"!!

After you look thing's over, tell us your findings...

Ride safe, Ted
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Offline DC Concours

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Re: 87 Fuel Leak/Dripping
« Reply #18 on: April 30, 2018, 06:54:47 pm »
It seems that you haven't yet figured out exactly where you are leaking from. Wipe dry and try again. Hydrolocks are an issue especially on older bikes. There are however tens and tens of thousands of bikes out there, this and other models, that have similar carb setup which are starting just fine with no hydrolocks. It is not as prevalent as it may seem. Do get the overflow tubes, they are a good insurance.


How many miles do you have on your bike?

Offline WillyP

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Re: 87 Fuel Leak/Dripping
« Reply #19 on: April 30, 2018, 08:16:57 pm »
On blowing air into the tube: If air flows, the air will simply flow out the vent for the carbs, as the overflow tubes are doing there thing and not allowing the carbs to overfill in the event of a malfunction of the float valve. If the air is blocked, the tubes are not installed, and you won't be able to blow air into the carbs at all.

The factory reason for the nipples is to drain the carbs, the screw with hex socket head, near the nipple, can be opened to drain the fuel out of the carb bowls, if so desired.

Also, as the bike may have had previous owners perform repairs of dubious quality, you should follow those tube up to where they originate, and not rely on them being correct.

Also, it's not the tank that you are concerned about over-filling, the carbs can over-fill even when the tank has barely any fuel in it.
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Offline LeeM

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Re: 87 Fuel Leak/Dripping
« Reply #20 on: May 01, 2018, 03:42:28 am »
PapaFrederico you are right, the bike has a vacuum petcock. I recommend you stop turning the reserve valve lever. I recommend you install a petcock parts kit if it leaks.

You mentioned buying a tank of gas. Note that the season is changing, and in California the fuel blend changes. What I believe happens is when the fuel blend changes, the neoprene tip of the needle valve and the neoprene parts of the vacuum petcock swell for a few days and then the parts shrink back to size when the added or removed smog additive penetrates all the way through the neoprene.

My experience is, the vacuum petcock started to leak and I would ride to work and people would tell me I stink. I had been turning the petcock valve to figure out just how many miles I could drive on a tank of fuel.

My solution is, I rebuilt the vacuum petcock with a Murph's Kits rebuild kit, confirm the vacuum diaphragm works, turn the valve to "Reserve". Then never turn the reserve valve lever.

My bike gets 145 miles per tank. I use the trip meter and buy gas at 100 to 120 miles. I simply don't turn the petcock lever.... ever.

When removing the Fuel tank, carefully label the three vapor recovery hoses. Keep track of the two rubber knobs that support the front of the fuel tank.

I also now add one dollop (1 oz or less) of tcw3 two stroke engine oil each tank of gas. The tcw3 has additives to keep water (and ethanol) in suspension. Recommended by Steve in sunny Florida.

Offline DC Concours

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Re: 87 Fuel Leak/Dripping
« Reply #21 on: May 01, 2018, 04:05:33 am »
why would you always leave it on reserve? And I think you're getting very low miles per gallon. I usually refill at about 230 miles which for me is a little after I turn on reserve.

Offline Bud

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Re: 87 Fuel Leak/Dripping
« Reply #22 on: May 01, 2018, 09:48:34 am »
PapaFrederico you are right, the bike has a vacuum petcock. I recommend you stop turning the reserve valve lever. I recommend you install a petcock parts kit if it leaks.

You mentioned buying a tank of gas. Note that the season is changing, and in California the fuel blend changes. What I believe happens is when the fuel blend changes, the neoprene tip of the needle valve and the neoprene parts of the vacuum petcock swell for a few days and then the parts shrink back to size when the added or removed smog additive penetrates all the way through the neoprene.

My experience is, the vacuum petcock started to leak and I would ride to work and people would tell me I stink. I had been turning the petcock valve to figure out just how many miles I could drive on a tank of fuel.

My solution is, I rebuilt the vacuum petcock with a Murph's Kits rebuild kit, confirm the vacuum diaphragm works, turn the valve to "Reserve". Then never turn the reserve valve lever.

My bike gets 145 miles per tank. I use the trip meter and buy gas at 100 to 120 miles. I simply don't turn the petcock lever.... ever.

When removing the Fuel tank, carefully label the three vapor recovery hoses. Keep track of the two rubber knobs that support the front of the fuel tank.

I also now add one dollop (1 oz or less) of tcw3 two stroke engine oil each tank of gas. The tcw3 has additives to keep water (and ethanol) in suspension. Recommended by Steve in sunny Florida.
Unless I'm riding on the aggressive side, I usually switch to reserve at 240 miles.  If you're only getting 145 miles to a tank, you have problems of your own.  You might want to start a new thread asking why your fuel mileage is 20 mpg.  That would concern me if it were mine. My 92 5.7L Buick Roadmaster with over 200,000 miles will get 20 mpg doing 80-85 mph all day on the interstate.  As for leaving it on reserve, that is a good way to find yourself sitting on the side of the road with no fuel.  Leaving the petcock in the on position is fine.....reserve...not so much.  If I were in your shoes, I'd hope someone would say this to me.  HTH

Offline DC Concours

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Re: 87 Fuel Leak/Dripping
« Reply #23 on: May 01, 2018, 12:26:43 pm »
And not to mention leaving it on reserve all the time is a good way to invite a hydro lock.

Offline connie_rider

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Re: 87 Fuel Leak/Dripping
« Reply #24 on: May 01, 2018, 02:07:09 pm »
DC, "Reserve" position on the petcock operates exactly like the "Run" position. {Both are vacuum operated}
I think your confusing Reserve position with "Prime" position which can lead to hydrolock! {mechanically opens fuel flow}

Ride safe, Ted

Still waiting to hear from Papa about his test results?
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