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When I turn my right fuel pepcock to prime my carb furthest on the left leaks gas. When I turn my left on to prime some hole that doesn't have a plug, which I'm still trying to figure out WTF its used for, leaks gas. What the hell is going on with my bike? Any and all help greatly appreciated.
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78 xs11 -
Fuel leaks
Sounds like your lefthand carb has a stuck float. Give it a couple wacks with a plastic screwdriver handle. If that doesn't do it, you may have a fuel valve in the bottom of the carb leaking, or a float that sinks, leaving the fuel valve stuck open. Is the hole that is leaking on the left side on the petcock? There are two nipples on the petcock. The front one is prime, and the back is run/reserve. Do you have an octopus vacuum valve still installed on your bike? The way most of us handle the octopus valve is take one step back and jump shoot it into the trash recepticle of your choice. Plug the front nipples on the petcock with a 3/16 vacuum nipple cover, run the hose from the left rear petcock to the bottom fuel tee on the right hand pair of carbs. The top tee is a vent for the carb bowls. Do the same on the right hand petcock to the left hand pair of carbs. Put an inline filter between the tank and the carbs so you don't get gunk in them. The top tees go to the airbox if you have a stock one. Make sure the vents are open or the carbs will leak. Don't connect the fuel lines to the top (vent) tees on the carbs. If you do they will overflow. Do you have a manual? Catatonic Bug has downloads if you need one. Good Luck!1979XS1100SF
K&N's and drilled airbox
Jardine 4in1
Dunlop Elite 3's
JBM slide diaphragms
142.5 main jets
45 pilot jets
T.C.'s fusebox & SOFA
750/850 FD mod.
XV 920 Needle Mod.
Mike's XS plastic floats set at 26mm
Venture Cam Chain Tensioner -
Tim,
His bike is a 78 so he doesnt have the octy b/c his petcocks are are vac operated, and his carbs doesnt have the extra vent 'T' on them. You could be right on about the stuck float or a "sunk" float. It not uncommon for the carbs to over flow when left on PRI (prime) if the float needle seats dont seal 100%. Not a huge problem... PRI is used for tuning and if you run your carbs dry, it will fill the bowls (and possibly more) without running the engine. When on PRI it allows fuel to flow freely to the carbs any time, if you leave the petcock on ON (if working properly) it will only allow fuel to flow when the engine is running b/c a diaphram opens within the petcock to allow flow. Regarding the "hole" that is leaking...we could use some more info to determine what it is and why its leaking (where exactly is it, pictures work good)... You can find almost everything you need to know about leaking carbs/petcocks in the tech tip or by searching the tech discussion area... GLLast edited by WMarshy; 07-17-2010, 07:33 PM.'79 XS11 F
Stock except K&N
'79 XS11 SF
Stock, no title.
'84 Chevy K-10 "Big Blue"
GM 350, Muncie SM465, NP208, GM 10 Bolt with 3.42gears turnin 31x10.5 Baja Claws
"What they do have is an implacable, unrelenting presence and movement that bespeaks massive power lurking behind paint and chrome. They don't wail like a screeching ninja, the don't rumble like a harley. They just growl like a spactic, stressed out badger waiting to rip your face off and eat your soul." Trainzz~RIP~Comment
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Originally posted by WMarshy View Post
Hmmm...last I knew the 78-79 model carbs (the stock ones for those bikes anyway) do have the top vent T. It was not until the 80 model year with the newer carbs with the 4th hole for a vent in the inlet bell that the vent T was eliminated.
As to this idea that leaving your bike on prime will lead to leaking no matter what, I still have to say that this is bunk. IF your fuel valves in the carbs are good, they will not leak. The force of the fuel on that valve does not change over time no matter how long they sit. Now, this does not mean I do not advocate turning the petcocks off one way or another when leaving the bike, I do by all means.Last edited by DGXSER; 07-17-2010, 07:50 PM.Life is what happens while your planning everything else!
When your work speaks for itself, don't interrupt.
81 XS1100 Special - Humpty Dumpty
80 XS1100 Special - Project Resurrection
Previously owned
93 GSX600F
80 XS1100 Special - Ruby
81 XS1100 Special
81 CB750 C
80 CB750 C
78 XS750Comment
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78 carbs DO have the top vent T. And until we have pics we cant say for sure there is not an octy (there should not be one but you never know). I bought a "Stock" 78 before I knew anything about them. I had an octy and a special tank on the bike. Anything is possible on 30+ year old bikesOriginally posted by WMarshy View PostNathan
KD9ARL
μολὼν λαβέ
1978 XS1100E
K&N Filter
#45 pilot Jet, #137.5 Main Jet
OEM Exhaust
ATK Fork Brace
LED Dash lights
Ammeter, Oil Pressure, Oil Temp, and Volt Meters
Green Monster Coils
SS Brake Lines
Vision 550 Auto Tensioner
In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.
Theodore RooseveltComment
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Ok...maybe Im missinformed about the second vent on the older carbs...it has been longer than a year since I had mine out. I only remember hooking up the fuel supply hose from the petcock to the carb T's and the vac line from the carb holders to the petcocks to operat the diaphragm and thats it...dont recall any other vent-T...Originally posted by DGXSER View PostHmmm...last I knew the 78-79 model carbs (the stock ones for those bikes anyway) do have the top vent T. It was not until the 80 model year with the newer carbs with the 4th hole for a vent in the inlet bell that the vent T was eliminated.
As to this idea that leaving your bike on prime will lead to leaking no matter what, I still have to say that this is bunk. IF your fuel valves in the carbs are good, they will not leak. The force of the fuel on that valve does not change over time no matter how long they sit. Now, this does not mean I do not advocate turning the petcocks off one way or another when leaving the bike, I do by all means.
In anycase, I agree that the carbs should not leak if the petcocks are left on PRI...BUT, its also very common for the float needles to leak/weep enough to flood the air box, and worst case fill the oil sump up with gas. IF they seat properly you wont have that problem but for many like myself who have clean carbs, the float needle valves just cannot be trusted. Leaving mine on PRI or even ON will result in gas in the air box (due to leaky petcock diaphragm and float needle valves). Thats why I did psychoreefers petcock mod...
True, anything is possible, I wouldnt underestimate anyones stupidity.Originally posted by natemoen View Post
Pictures are worth a thousand words...
'79 XS11 F
Stock except K&N
'79 XS11 SF
Stock, no title.
'84 Chevy K-10 "Big Blue"
GM 350, Muncie SM465, NP208, GM 10 Bolt with 3.42gears turnin 31x10.5 Baja Claws
"What they do have is an implacable, unrelenting presence and movement that bespeaks massive power lurking behind paint and chrome. They don't wail like a screeching ninja, the don't rumble like a harley. They just growl like a spactic, stressed out badger waiting to rip your face off and eat your soul." Trainzz~RIP~Comment
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And its not always stupidity (although it often is) with the gas tank on mine the PO said the tank he had rusted out and he bought a new one. Not sure how he missed the fact that it didnt look the same or that the petcocks were totally different but he did get the octy to go with the different petcocks. Ya just never know!
Sorry to be off topic!Nathan
KD9ARL
μολὼν λαβέ
1978 XS1100E
K&N Filter
#45 pilot Jet, #137.5 Main Jet
OEM Exhaust
ATK Fork Brace
LED Dash lights
Ammeter, Oil Pressure, Oil Temp, and Volt Meters
Green Monster Coils
SS Brake Lines
Vision 550 Auto Tensioner
In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.
Theodore RooseveltComment
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Thanks for the help. Carb tap seemed to do the trick, doesn't drip anymore but if I run my hand over it I can smell the gas on my hand. The "hole" I'm referring to is located physically just under what I believe to be the air filter. I'm new to these things so I got the manual download but nothing refers to it. The hole seems to actually be a built out square or rectangular piece with a hole in the bottom that leaks every time I the bike up straight.78 xs11Comment
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Hey Turbo,
That square hole in the bottom of the airbox IS the drain for the airbox for WHEN they get filled with leaking gas from the carbs. So...you've still possibly got carb leaking problems....float needles and seats, or also floats.
You'll want to check your oil for presence of gas....because the carbs can leak forwards as well as backwards, and get down into the intake, then cylinder, past the rings and into the oil. Then it messes up the bearings and you can burn up the engine/crank quickly!
Take a stick, stick it in the crankcase filler spout, get some oil on it, then step FAR away from bike, garage, and then take a lighter to it and see if it will light! If so...then it's contaminated with gas, need to change oil/filter.
BUT first fix the leaking carbs!
T.C.T. C. Gresham
81SH "Godzilla" . . .1179cc super-rat.
79SF "The Teacher" . . .basket case!
History shows again and again,
How nature points out the folly of men!Comment
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The gas only seems to drain out when I'm sitting the bike straight up. Once straight up it just drips to a stop. Does this mean the leak could be positional or is this effect regardless of the location of the leak?78 xs11Comment
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No. The hole is in the center, and any fuel left in the airbox will only drain out when the bike is centered. Try dropping the airbox and cleaning it out. As long as the leak in the carbs is fixed, that should stop the airbox from dripping.Originally posted by turbo loco View Post1980 XS850SG - Sold
1981 XS1100LH Midnight Special (Sold) - purchased 9/29/08
Fully Vetterized and Dynojet Kit added, Heated Grips, Truck-Lite LED headlight, Accel Coils, Irridium plugs, TKAT Fork Brace, XS850LH Final Drive & Black SS Brake lines from Chacal.
Here's my web page devoted to my bike! XS/XJ User's Manuals there, and the XJ1100 Service Manual and both XS1100 Service manuals (free download!).
Whether you think you can, or you think you cannot - You're right.
-H. FordComment
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Good call on dropping the AF. It was leaking just what was left and had me thinking it was continued. Fires up and doesn't leak. Starts smoking from the left exhaust right below my shifter. Is this common afterwords or am I in a world of trouble now?78 xs11Comment
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Smoke is probably oil that has leaked from the shifter shaft down onto the header/pipe. There is oil behind that cover, and the rubber seal will get old/ dry and leak a bit. It's not really under much pressure there, just a catch area, and for the shifting mechanisms/parts.
T.C.T. C. Gresham
81SH "Godzilla" . . .1179cc super-rat.
79SF "The Teacher" . . .basket case!
History shows again and again,
How nature points out the folly of men!Comment
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And if the oil leaked there does it have to do with gas getting into it from the carbs or that in itself is a separate issue?78 xs11Comment
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Separate issue entirely. Can you tell if there is a leak from the shifter shaft? Any oil on the pipes will smoke, but only until it's been burnt off. Try giving the bike a bath and see if it still smokes there.Originally posted by turbo loco View Post1980 XS850SG - Sold
1981 XS1100LH Midnight Special (Sold) - purchased 9/29/08
Fully Vetterized and Dynojet Kit added, Heated Grips, Truck-Lite LED headlight, Accel Coils, Irridium plugs, TKAT Fork Brace, XS850LH Final Drive & Black SS Brake lines from Chacal.
Here's my web page devoted to my bike! XS/XJ User's Manuals there, and the XJ1100 Service Manual and both XS1100 Service manuals (free download!).
Whether you think you can, or you think you cannot - You're right.
-H. FordComment
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