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Retired twice: Navy and as a govt contractor
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Discussion Starter · #1 ·
at least I think it is the overflow.

Started bike for the 2nd time this year. Started on full choke after aa bit of cranking. Went to push the choke in a bit and noticed fuel running out of a hose on the left side up by that side air filter. Have not had a chance to look at it yet, but I am open to suggestions where to look. I have a Clymer hard copy manual and an electronic Yamaha service manual.
yer

Thanks John
 

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Assuming it's the carb overlfow and not just a leak, you probably have a stuck float or dirt in the float valve that shuts off the fuel.
You may have to take the carb bowl off but there is a trick you can try first, it may clear it up if you just have a tiny speck of dirt stuck in there, pinned by the pressure of the float trying to shut off the fuel since the bowl is full.

Turn off the fuel at the petcock.
Run the engine until it's out of fuel. This will empty the bowls of fuel and make the floats drop down, opening the inlet valves to the bowls wide. ( you can also drain the bowls by opening the drains at the bottom but I'm not familair with your bike so I don't know what it looks like)
Open the petcock, if your lucky the dirt is dislodged and the flow of fuel through the wide open valve will flush out the dirt.
You can try this a few times, you can tap on the carb while empty too to shake things up a bit.
If it doesn't work and still keeps overflowing you'll have to open up the carbs and see what's going on, but this fixed this exact problem on my Honda on the side of the road one day and it's been fine for 3000 miles since then.
 

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Retired twice: Navy and as a govt contractor
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Discussion Starter · #4 ·
Okay here is where I am (lost). Air comes in through these boxes on the top
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That feeds air inside to the carbs here

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I cannot get those covers off, but can peel them back so I can see inside. Air goes through the carb picks up fuel and exits through the bottom into the engine. they look like this from the sides. I do not see a bowl.


Automotive tire Automotive lighting Hood Motor vehicle Vehicle


other side looks the same.

I cannot see an oil line in the window so I am going to assume there is gas in the engine. I am going to get something to run clean fuel into it but not sure if I should change the oil first. I will spray carb cleaner down the throats and hope for the best.

I am open to suggestions.
 

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Discussion Starter · #7 ·
See number 13 and 19 in parts diagram. I think the 'covers' will come off after you loosen the screws in those clamps. (Four total, one directly on top of each carburetor). The rubber air ducts will probably be kind of stuck to the carbs so you may need to 'work' them a little. There are some small drain hoses and such in the cover that have to be unplugged for removal. Study the diagram to get an idea about that.
EDIT: You'll need to loosen clamps #52 and #53 also then 'work' the covers out. With all of that stuff to deal with it might be good to take close up pics as you go for help putting it back together later.
Found another bolt (#15) on the parts diagram. Haven't removed it yet, but that will allow me to remove the cover. Then I can get the airbox off by loosening all six hose clamps and gently working it loose. That was my plan for today, but got dehydrated yesterday and I am paying for it today.

I ordered this: working fuel tank from Amazon. Came in today.


The fuel bowls are located directly opposite from the carb caps (other end) of the carburetors in your pic number three and are not numbered in diagram but #12 is the drain screw located in the bottom of the fuel bowl. When I recommended using the fuel bowl drain screws to remove / install B12 I did not realize they were hidden under all that stuff.
Yeah I can see them buried up in there. I think once I have that airbox off I will have better access to them. I can see the bleeder screws but at the moment I need at least a 6" long Allen to get to them. Will see what it looks like with the box off..


Yes, change the oil and filter before any attempt to run or even turn the engine over. Change again if there is any question that fuel may have gotten in the oil again. Cheap insurance.

Keep us informed, post pics and ask questions as you go if need be.

I could not see an oil line in the sight glass so I changed the oil and filter. I now have a nice clean oil line halfway up the glass. I have to work in the driveway in the sun and I am taking my time. Have drained the full gas tank and mixed that fuel into my 30+ gallon truck tank. It looks like there are two overflow lines one for each bank of carbs. If that is true then my problem is probably on the left bank. My plan for now is to drain all 4, fill them with straight B12 and let the sit for a while. Monday I will tap the heck out of the carbs, put more fuel in it, turn the key and pray the fuel pumps shuts off when it should. I will let you know, thanks for all your help.

All else fails I can load it on a trailer and head north to Mike's. :)
 
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Discussion Starter · #8 ·
Finally got the airbox off, it was easy really. Hooked up my temp fuel tank with straight B12. Looked around and found a stuck slide on the right front carb. Also found out that the overflows crisscross and the right side drains down the left and vise versa. Turned the fuel pump on and it pumped and shut off without anything running out.

With high hopes I went out and found a reduction adapter so I could connect the temp tank correctly. Tank is now 50/50 Sunoco and B12 Turned the key on fuel pump kicked on built pressure and shut off like it is supposed to and no leaks anywhere. I hit the starter and it cranked for a bit and started right up. It also started spitting fuel out the over flow. Shut everything off and went back inside.

I tapped and tapped everywhere I could and tried again. Same result. I will try again tomorrow after it has sat over night. My allen wrenches aren't long enough to get to the drains and there are hoses and cables in the way for good access.

I have it narrowed down to the right side and I believe it is the front carb. Part, actually a lot of my problem is that my eyes will not adjust to see clearly in the range I have to work in. My progressive glasses are worthless and my dime store cheaters are quite good enough.

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Discussion Starter · #12 ·
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This is what the fuel looked like going in this morning.

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Looked like this coming out.

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2 tanks later they looked like this

It runs but is still spitting fuel out of that over flow. In the picture below if I blow air in the overflow it comes out of the marked orifice in the picture below. If I blow air in that orifice it comes out the same hole in the other carb on that bank. Slides move freely and the bike responds to the throttle still spitting fuel. Won't idle because the carbs are wide open to the outside.
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The other two holes spray a fine mist of fuel into the barrel of the carb.

Drain plugs I still can't get to, I am going to have to get another set of allen wrenches with longer shanks or that will fit my socket set.
 

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Sorry you’re having such a workout! How old is that fuel? Has your bike been sitting for a while? Hang in there brother you’ll get it. For what it’s worth I always added fuel stabilizer after my bikes were on “E” before filling them when I was preparing for “down time.” I rode the machine a few miles afterwards to assure it ran thoroughly through the fuel system. An extra in line fuel filter never hurts. I never experienced any problems when starting up after the bikes sat for a while unused. I did this religiously every fall in New England for many years. I’m sure you know this this already. Just saying. Good luck. The wind misses you!
 

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Discussion Starter · #14 ·
Anthony it was full and had a half a bottle of staybill in 5 gals of fuel. That was done before my open heart surgery in summer of 18. I have started it every couple of months but only ridden it 3-4 times since then. I was afraid of the weight if I had to hold it up and what it would do to my surgical scars. Everything was fine until this time around. Started right up but spewed fuel out the overflow. I have been trying to get it the float unstuck to no avail. At 76 my eyes aren't what they used to be and after this go around I am going to put it back together and see if I can't find someone that can fix it. Once it is running I will go through it and sell it. My Harley is over 100 lighter so I am ridding that for now. Will probably sell that as well and get something smaller.
 

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Discussion Starter · #15 ·
Semi, bought some new longer allen wrenches and tried those. Still not long enough to use but I could get them on the drain nut. So now knowing the size I dug through all the loose allens in the bottom of the drawer and found my longer 5mm wobble and a 5mm t handle. between the two of them I managed to drain the bowls. Fill them and drain them again. When I fill the bowl just a tiny amount of fuel comes out as the pump shuts off. If I turn the ignition back on after a few minutes fuel comes rushing out. It all most looks like more than before. 🤷‍♂️ I am going to let it sit over night as it drains all over itself and I want to let it evaporate before I try again.

But I think I am a stage were I am going to have to bite the bullet and find a professional. Thanks for all your help. Below are pictures of the drains.

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Thanks for all your help. John
 

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Sounds like a plan. My Harley’s a lot simpler than dual or triple carb set up for sure. Mine’s a single carb 84 FLT. What year is yours? Incidentally Stable is only good for two years at best. Things do get gummed up after that. Good luck with the sale.
 

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Discussion Starter · #17 ·
The Yammy is a v4 with 4 carbs in the valley of the cylinders. My 88 FXSTS has a single carb hanging out in the open,

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I am going to let it sit over night as it drains all over itself and I want to let it evaporate before I try again.
Yeah if sitting overnight a few times with a full load of straight B12 isn't enough to clean off and let the float valve/s seal then most likely there are more gummed up parts inside the carb's that need attention anyway.
I was just hoping all it needed was a few good rinse and repeats.

S F
 

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Incidentally Stable is only good for two years at best. Things do get gummed up after that. Good luck with the sale.
Two Years??? WOW! You guys must get some good fuel up there. Maybe it's because you have COLD temps that we don't have in the Houston area. I have heard of winter blend fuel. I wonder if that's the difference?
With the ethanol fuel we are forced to use it's more like three weeks of sitting and the damage has begun, even with Sta-Bil in the fuel.

S F
 
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