Carb Overflow Leak

[Anonymous]

Ok, a while back some of you graciously tried to help me sort out a problem that I was having with my bike's engine mysteriously dying. I think I have that end of the problem fixed now so I am moving on to the next headache.

The bike is a '77 GS550 with 12k miles on it. I have only owned it for a couple of months, but it appears to have been reasonably well taken care of.

The current problem I am having is that I am getting one heck of a fuel leak out of the overflow hoses on carbs 1 and 2. I had the carbs off while I was working on the bike and they appear to be clean (they were supposedly cleaned at the dealer before I picked up the bike). The floats do (float), and the float needles are clean and appear to be in good shape. I didn't tear the carbs apart to the extent that I could inspect the seats though (mistake #1). I also did not measure the float height (mistake #2). Originally, the leak was not terribly bad, but it seems to have become worse since I re-installed the carbs, now wetting the concrete under the bike when it is parked.

I have assumed that the problem is in the needles and/or seats, but I am confused as to why gas continues to spew out of the hoses when the bike has not been run for several days. If the fuel valve is operating correctly, shouldn't the leak be no worse than the amount of fuel left in the line when the bike is shut off? The vacuum system should not be feeding fuel if the bike is not running, correct? The line is never empty though (installed clear lines to help isolate a fuel starvation problem previously).

The bike is also gas-fouling plugs with the air screws set at the factory-spec. 2 turns out. I have since taken them out to 2.5, but haven't ridden enough yet to re-check due to the fuel prob.

Sorry for the long post, but I wanted to give you as much info as possible.

[Anonymous]

it would have to be a bad needle valve, fuel filter installed???

[Anonymous]

Yep, fuel filter installed prior to my ownership, and a new one installed by me when I replaced the fuel line.

[Anonymous]

I have just had the same problem, it turned out that on the Gs 1000s the fuel tap is of a vacuum type without a tap. I had the carbies of because of the same puddle under the bike, turned out to be the fuel tap was faulty.
The needle and seats are new but will not hold the fuel back when the tap does not seal.Check to see if the tap is in the prime position this will cause flooding

[Anonymous]

Yeah, I should check the fuel valve before I pull the carbs again - those things were a real pain to put back on! I had the valve assembly off when I was checking the fuel problem, but I didn't pull it apart. Like I said, something seems screwy with the valve if gas is continuing to feed to the carbs even when the bike hasn't run for several days. If there is no vacuum, there should be no gas feed, correct?

The valve is in the "On" position.

[Anonymous]

if you have the vaccuum type petcock there is a small diapragm in it that might have a very tiny hole in it ( you might not see it even if you take it apart) If that is the case, it will mark its territory every time you park it, and worse let gas into the cylinders. Had this problem with my 1100 paid 50 bucks for a new petcock and installed it in about 15 minutes. There is also a rebuild kit available , I think, but I didn't have the patience to go that route.

[argonsagas]

It does sound like you have a petcock problem. You really must take care of it as it can cost you your engine....with all that gas running out on the floor you can be sure some is going through the manifold and into the engine, and mixing with your oil.

Fix the problem and replace the oil. Don't drive with an oil/gas mix.

FYI putting the carbs on can be a pain.....i'll tell you what I do, and why, but it really is not a recommended way to go.

Mechanics said the carbs just slip on by pushing....not mine.

I tried spraying the intakes with silicon and pushing them on by hand. Didn't go. Pushed harder...wiggled them.....same result. Increased pressure....pushed MUCH harder....bike came off the centrestand and fell over.

Tried using 24 inch F-clamps left and right and over the engine, with a long piece of wood over the carbs...slipped a few times, but it worked. Did that a couple of carb changes and wasted a lot of time with the slipping. This is not a bad idea, but you probably need a block of rubber or something like that on the engine, to prevent the clamp from slipping.



Now I use the Original Mechanic approach....If it don't work, get a bigger hammer.

I spray the carbs and inlets, position the carbs against the inlets, place a 2 foot long piece of 1 x 3 pine over the entire carb bank and hit the wood with a hammer. Carbs are on in 30 seconds. NOT recommended, but it works. (I have an advantage....having had a hammer in hand, and having used it seriously, since I was 5, I really DO know how hard it hits, and it hits accurately)

[Anonymous]

It does sound like you have a petcock problem.
Fix the problem and replace the oil...
FYI putting the carbs on can be a pain.....i'll tell you what I do, and why, but it really is not a recommended way to go...

Mechanics said the carbs just slip on by pushing....not mine.

I tried spraying the intakes with silicon and pushing them on by hand. Didn't go. Pushed harder...wiggled them.....same result. Increased pressure....pushed MUCH harder....bike came off the centrestand and fell over....

I spray the carbs and inlets, position the carbs against the inlets, place a 2 foot long piece of 1 x 3 pine over the entire carb bank and hit the wood with a hammer. Carbs are on in 30 seconds. NOT recommended, but it works. (I have an advantage....having had a hammer in hand, and having used it seriously, since I was 5, I really DO know how hard it hits, and it hits accurately)

Well, I would rather have a petcock problem than a carb problem I suppose as I can have the tank and petcock off in about 10 minutes as opposed to the sweating, swearing, more sweating, and of course more swearing that accompanies installing the carbs.

I'm game for any idea that minimizes the carb headache. I was hoping that I was not the only one that nearly knocked their bike off of the centerstand while attempting to get the carbs back in. Yeah, Clymer says it will slip back in too...sure, whatever.

I'm trying to visualize the manuever that you described. Are you saying to line the carbs up with the inlets on the engine and airbox and then just wack the figurative snot out of it with a downward strike and they will pop back into place?

Hopefully I won't have to take them back off anytime soon and the petcock is the problem. My luck does not seem to lend it self to the simplest solution in most cases though.

[Jay B]

Man you guys got some tight fittings. Little spray of WD 40 and mine slide on like skates on ice.

[SqDancerLynn1]

If you are working on your bike on the center stand DON'T forget the factory put slots for a locking pin in the centerstand. No reason to have it fall. After the bike has been used for a few hours the carb boots will soften up and they will slide right on. Or you can warm them up with a hair dryer. check the fuel valve, run a hose from the fuel valve into a container to see if it is leaking fuel while it is parked overnight. Chances are that it will need to be rebuilt if you haven't done so. It is not a dificult job. Just make sure to put it together properly (index vent hole)

[Anonymous]

Vent hole??? what vent hole???? I'm in the middle of rebuilding my carbs right now and this sounds really important. It's the first time I have done this and I'd like to get it right

[SqDancerLynn1]

It has been awhile since i had my fuel valve appart. it seams to me I remember having to rotate the vacuum diafram assemble for correct assembly Take a close look when you take it appart