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Discussion Starter #1
Hey guys, need some feedback. Have a 07 RoadStar w/carb when, 3-5 minutes after hot shut down, the carb pisses fuel out the bottom, back of the air filter housing, at the drip hole opening. Gas then runs along the back of the rear push rod base, along the engine case, then onto the ground, leaving a silver dollar size wet spot on the ground. This happens a lot!

I've been back to the Yamaha dealer 3 times about this and they have changed the needle assy. for the float and cleaned out the carb. The problem continues. They are now telling me that this is "normal" for hot engines having been shut down because the fuel boils in the carb and expands, burping fuel out as I have described.

Are they giving me a line of crap or are others having this same issue or have heard of this problem? Thanks for any input received.

Buck
 

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That is a true a statement about fuel boiling. It may or may not be your problem. I would try taking the fuel cap off after you park and see if it does it. Possibly a vent issue.It could be something simple as that. It's cheap and worth a try.Let us know.
 

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Discussion Starter #4
Here is another update after yet another visit to the dealership about this. I am told that the vent to the tank is open and clear. I am also told that Yamaha does not put a carb, float bowl overfill tube on these carbs due to EPA regs that say they can't dump raw gas on the ground. Yet, if the float bowl overfills, the gas will come out the carb throat and drip into the airbox...and...you guessed it...the gas winds up on the ground again.

Anyway, my dealership has thrown their hands up in the air on this and is deferring me to the regional rep. I will be having a meeting with him when he makes his next stop at the dealership in a week or two. If nothing else, their concern has to be the fuel winding up on the ground which is a no, no. I'll keep you posted as to what...or what not, is the next thing Yamaha is going to do to try and correct this problem. That is, if my bike don't burn up first!

Thanks all.
 

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If you need any help backing you let me know. I dont know if im still going to have the problem when I get my bike back, but having the problem to begin with is absoutely unacceptable. Keep us posted if they find a fix. I dont want to look like Ghost Rider going down the road.
 

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Discussion Starter #6
I will certainly keep information coming on this. Yeah, it is a little unsettling knowing that there is raw fuel running out onto an extremely hot engine! There is a small cavity behind the rear push rod base where the fuel pools up and lays there until it evaporates with the heat. I have come to leaving a window open in the garage cause the fuel stink is so bad.

This is the 4th Yamaha I've owned with this basic engine, and none of my other bikes had this issue. I've had a 99, a 2004, a 2008 (injected) and now this 2007. This is the only one with this problem.
 

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Discussion Starter #10
Okay!!! Just got a call from my Yamaha dealership and the news Directly from Yamaha is; Yamaha is definitely aware of this gas leaking problem among carbureted Road Stars:eek:. I do not know how extensive this problem is however. They have been working on a "fix", but nothing conclusive yet:mad:. I am to be notified as soon as a solution has been devised so that my bike can be scheduled for the repair. How long will this be:confused:? I don't know...but I am told it is a top priority at Yamaha. Once this plays out I am sure there is going to be a TSB released.

Will post again when new information becomes available.
 

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Discussion Starter #12
Have you been riding the bike in hot weather letting the engine stay really hot before shutting it down? It has been a bit cooler here lately and mine has stopped leaking as well. I think when the temp goes up, the fuel boils, and the overflow occurs. Let me know what temps you are riding in.
 

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Discussion Starter #14
Yeah,
I have made a definite connection between the outside temp and the overflow problem. During my cooler riding days last week...no problem. This week, with two days already hitting the high 80's, the problem is back. I stopped at the video store yesterday on the way home from work, and when I got back out to the motorcycle there was gas puddled on the right side of the engine and on the ground. How embarrassing! Of course the strong smell of raw gas was noticeable as well. I hope Yamaha comes up with something pretty quick. Keep in touch.
 

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BUMP Anything new on this issue? My bike is doing the same thing. I guess a trip to the dealer on Tuesday is in order.
 

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Discussion Starter #16
Yeah...this is an issue that many of us have in varying degrees, but not many of us complain to Yamaha about. After my many complaints at the dealership level I eventually went up the ladder and complained directly to Yamaha.

The Yamaha district rep explained the "problem" to me this way: The gas overflow, exiting from the throat of the carb after a hot engine shut down, is caused by vaporization and pressure build-up in the float bowl due to fuel boil. He backed up what the dealership tech has been telling me for the last 7 months by saying that Yamaha has no current solution for the problem...but...they are aware of the complaints and are looking into it.

As a non-authorized remedy the dealership offered to wrap the bottom of my carb with a heat reflective tape. They thought this might defer enough of the heat generated by the cylinders to stop, or at least limit, the overflow incidence. IMO this is a band-aid and I really don't like the idea.

Since we are now in our winter months I chose not to have this service performed, and with the colder weather the problem goes away. I expect it to return in about 3-4 months with the warmer weather. I have not made up my mind what I am going to do yet. I may continue to nag Yamaha directly until they recognize that this is a safety issue whereby if the gasoline ignites personal injury could result. I really don't have an answer to this problem myself but I do know that it isn't right.
R
 

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Thanks, Rich. My bike didn't seem to do it today. I rode just over 100 miles in 80 degrees. Some days there is a nice little puddle of gas pooling on the engine case. I will take it to the dealer and see what they have to say.
 

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Wouldn't it be safe to say that the float bowl in under pressure so once you've creased riding the excess fuel pressure has to go some place? A lot more rider might note a stronger than normal gas odor a while after riding. I can say that it takes a little while after a ride to catch that strong smell or to actually hear the bike sound like its pissing.

The Dealership mechanic told the sale person who is a personal friend of mine that the film on the engine case was oil residue, If you park in a garage the smell is more present opposed to parking lots

Just my 2cents
 

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Discussion Starter #19
The carburetor float bowl should not, under normal circumstances, be under pressure. The float needle controls the amount of fuel entering the bowl and the float bowl fuel level, depending on fuel demand, but it is not designed as a pressure relief valve. The fuel bowl is vented to ambient. This is to serve mainly as the overflow path. The fuel vapor you smell is a result of excessive heat (fuel vaporizing) in the fuel bowl. Fuel overflow out the carb throat occurs when this heat builds to the point that it vaporizes the fuel at a faster rate than the vent can handle. Most times this will just be a burp or two until the fuel starts to cool. Other times it can make a real mess on the right side of the engine and even leave a gas puddle on the floor.

The solution to this known problem is currently being considered by Yamaha. I say..."Ha"!
 

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So I tired this tonight to see if it helps avoid the raw fuel spill. As I approached the garage I shut off the petcock, continued into the garage, parked and let the bike run out of fuel. It didn't take long, we'll see how bad the fuel smell is in the AM.
 
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