Question about Yamaha Motorcycles
When shutoff valve is turned on, gas flows out of small diameter hose connected to carburator
Posted by Anonymous on
Hi, Anonymous and the usual suspects are:
1. Damaged or restricted fuel tank venting system.
2. Loose float bowl screws.
3. Damaged float bowl o-ring.
4. improper fuel level in the float bowl.
5. Worn or dirty inlet valve or seat.
6. Damaged or leaking float assembly.
7. Particle contamination in inlet fitting cavity.
For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have nice a day.
Dirt Rider Magazine
Carburetor is leaking gas out of overflow tube need help
YAMAHA PW80 Owner Service Manual
OEM parts for Yamaha
YAMAHA PW80 Owner Manual
Posted on Dec 14, 2016
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Posted on Jan 02, 2017
Sounds like a stuck float. try gently tapping on side of carb near bottom where float assembly is located to see if it frees up if it doesn't you will need to remove and clean your carb and check your float adj.
Posted on Dec 28, 2008
If you had gasoline in your oil, there's only two ways for it to get there. It either came through the carb or someone poured it in there.
I've been messing with Harley's since 1966, back before they created these cute little names for the engines like Panheads, Shovelheads, Evolution, Blockhead, Fathead. We only had two engines, Sportster 61 cu. in, and the 74 cu. in. in the big bikes.
Now, the way the fuel got into your gasoline was through the carb. If you've ever watched an old timer get off his bike, he'll reach under the tank and turn the fuel off. This was keep what happened to you from happening. It worked every time. The problem these days is in their infinite wisdom, Harley has adopted the misguided conception that the Japs started, the vacuum operated petcock. The absolute worst invention man has ever designed and put on a motor vehicle.
Now, in both the petcock and the float bowl of the carb you have a "needle and seat" all it takes is one very small bit of trash to cause the gasoline to seep past the needle. Keep in mind now that gasoline has a lower viscositiy than water. It will go where water won't go. It's thinner. A lot of gasoline can seep past a needle and seat in a 12 hour period. I've seen fuel tanks empty themselves in that time.
I've fixed many bikes that had the vacuum operated petcocks on them. They started putting them on the bike in 1996. I've seen people stranded beside the road with full tanks of fuel but not a drop getting to the carb. I've seen gasoline pouring out the small vacuum line (probably what happened to you) after the engine had been flooded out due to a ruptured diaphragm. And, I've even seen a couple of cases where the engine was sucking air through the petcock and would not idle or even run very well.
Now, when you change the oil on a harley engine, you don't get all the oil out of it like you do on car engine or a Japper engine. There will be a certain amount of oil left in the top of the heads and the camchest. Also, the gasoline fills up the crankcases that are supposed to be empty of oil. If you have a quart of gasoline that has run down past the rings into the crankcase, you now have one extra quart of fluid in your oil system. Whenever I suspect something like what happened to you, I always take the spark plugs out and spin the engine over a few times to get any excess fluid out of the crankcase. It will blow it out of the crankcase vents which in your case is in the heads. Those big bolts that hold the air filter backing plate on are hollow and are actually crankcase vents.
So, in short, my suggestion is to take that vacuum operated petcock off your bike, plug up the vacuum hose, and purchase a high quality manually operated petcock like a Pingle. They're expensive but if you get into the habit of turning it off whenever you get off your bike, this problem will NEVER happen to you again.
BTW:, you need to check your primary oil to see if it's been diluted as well. The gasoline will go past the sprocket shaft seal and contaminate that oil as well. You're pretty safe on the transmission lube though.
Steve (old biker)\\\\\
Posted on Jul 11, 2010
Sounds like your carburetor floats are stuck to the bottom of the bowls. You can try to tap the carb bowl with a screwdriver and try to get them to pop loose, otherwise you will have to remove the float bowl (usually about 4 screws on the bottom of the carb). All you should have to do is pull it down about 1/4" or so until the floats pop loose and then put the bowl back on. This is pretty common on bikes that have sat for a few months, especially if you are good about draining the gas from the carbs when you're storring it.
Posted on Jul 14, 2010
SOURCE: Gas leake from Air vent
If you mean that fuel runs out of one of the vent lines, note that one of those lines is for overflow from the carb bowl. If this is what is happening, you might have corrosion or dirt making your float needle stick, and overflow fuel to that carb. It needs to be cleaned out by removing the bowl, float and float needle.
Posted on Sep 06, 2010
SOURCE: fuel leaking out of a
You need to remove carbs, clean float bowls, remove floats, fuel cut off valve under float, quite a big task so recomended fit new cut off valve in each carb, check also throttle slide mooves freeley before replacing, recently done the same job for customer, you could just clean float cut off valve but at twelve pounds each
ch you are best replacing them
Posted on May 12, 2011
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