Boiling Fuel Syndrome

[awryders]

I'm trying to post this at a motel.I just met a 05 FJR rider who had a serious issue with his fuel boiling

out of the tank today while on a KC to California trip.It's very HOT here in Nebraska and he was running

at a very elevated pace.. My question is,has this happened to anyone else ???? And if so what can be

done to make sure it won't happen again ????

 

[Woodstock]

What, exactly, were the symptoms? If it was just fuel coming out of the overflow hose, then it's not necessarily a problem, the overflow is doing what it's designed task.

If it was actually some violent "rolling boil" if you looked into the tank, then, um, I wouldn't stand that close.

 

[radman]

If he's running it hard enough to create the kind of heat that would actually boil the tank, then time to slow it down. It's bad for the motor as well as the other hazards that are involved. Otherwise a +1 on Woodys post. Keeping the tank at better than 1/3 full will help. Sometimes one just has to take conditions into account and adjust as necessary, despite what one would like to do. As far as fixing it, see this thread.

 

[Feejer/Weejer man]

There have been reports of this. The vent works on pressure. Some have reported that it takes a lot of pressure to relieve their vent tubes. One LD rider has taken his apart and drilled another hole to help the venting so this doesn't occur. At elevation, high temps and long hard hauls is where this will occur. I am not sure if it was an extra hole or rather the hole just drilled out larger. But he insists it made a difference.

 

[Rogue]

Mine wasn't venting and I got a lot of spray when I opened the cap on the way to WFO, I had a plugged charcol canister and vent line.

 

[Bounce]

Had a stream (not mist) of fuel shoot into my face in SLC back in 2003. I was lucky I wear prescription glasses or I'd have been hurting. I was very careful after that when opening the fuel cap for the rest of the trip. Reported temps were ~110 that day with actual heat on the pavement closer to 120°.

When I got back, I made sure my vent hoses were clipped at 45° (with the up-side facing the back of the bike) and also make sure that I service the fuel filler neck at least annually.

https://www.bikes-n-spikes.org/maint/ff/ff.html

Never had a problem like that since.

 

[awryders]

Thanks guys I'll pass the info on.

The link here in the motel sucks :angry2:

 

[timk]

I wonder if this could be caused by the increased alcohol they are putting into the gas.

 

[Alex]

I wonder if this could be caused by the increased alcohol they are putting into the gas.

I thought of the same thing. I had mine release lots of pressure when opening the filler cap twice on the way to wfo, yet when driving in the really hot weather in NV, I didn't have any, any pressure release when opening the tank. My overflow lines are not pinched, I checked after the first pressure release.

I do use 10% ethanol mix when filling in NE, but I've never had any boiling that I know of.

 

[jestal]

This definitely sounds like the tank is not venting during normal operation causing the sudden formation of LOTS of vapor when the pressure is released by opening the cap. Check the vent lines for sure.

Are these California bikes with the charcoal canister for evaporative emissions that are causing the problem the worst?

 

[zorkler]

Never had this problem and i run the bike hard at times the temps in new york get up there . so we might need the left coast people to chime in on this .

 

[weekend rider]

With all the fixes that have been mentioned and if none seem to work than what?

Consider this, the tank is designed operate at atmospheric pressure, sea level =14.5 psi.

You are at a high elevation say around 4000 feet.

I would consider the pressure and spray came from the 100+ heat and all the sloshing which help builds pressure. NOw you are at a now you decide to open the tankmore pressure in the tank than out side air, laws of physics take over, higher pushes lower end result a spray of gas this is what most likely occurred

if you find no vents plugged. A natural act of expansion and contraction from liquid to vapor

let the problem come to you and do not always think it had to be mechanical or electrical and you need a wrench to repair it. good luck post when you get problem solved weekend rider

 

[jestal]

With all the fixes that have been mentioned and if none seem to work than what?

Consider this, the tank is designed operate at atmospheric pressure, sea level =14.5 psi.

You are at a high elevation say around 4000 feet.

I would consider the pressure and spray came from the 100+ heat and all the sloshing which help builds pressure. NOw you are at a now you decide to open the tankmore pressure in the tank than out side air, laws of physics take over, higher pushes lower end result a spray of gas this is what most likely occurred

if you find no vents plugged. A natural act of expansion and contraction from liquid to vapor

let the problem come to you and do not always think it had to be mechanical or electrical and you need a wrench to repair it. good luck post when you get problem solved weekend rider

Even with all their faults I suspect that Yamaha might have considered that the motorcycle and tank would be used at altitude. They sell the bike in countries that have very high altitude roads. Chances are they even tested it at high altitude....LOL.

I would look for something wrong....period. No company makes a fuel tank that would spew fuel under normal conditions of heat and altitude. There must be a vent plugged for pressure to build that high. Fuel tanks are designed to vent and automotive fuel systems vent thru the evaporative emissions canister just like the California FJR's do.

 

[Cal24Master]

A couple of observations while messing with my 06 this weekend:

1. There is only one fuel line coming from the pump to the fuel rail now, instead of 2. There is no return line.

2. The Tanji cell flows MUCH better on the 06 than it did on the 03. I am wondering if the lack of a return line, and consequently lack of fuel getting heated in the fuel rail and returned to the tank contributes to the lower fuel temp, and possibly lack of positive pressure building up in the tank.

Since this is my first CA model, I wonder it the evaporative system, which uses vacume from the motor could actually cause the tank to have a negative pressure, which actually helps suck the fuel from the fuel cell.

Tom

IBA 161

 

[donaldb]

A friend came over last Friday and spent the night (wife was out of town) he just bought a used 05. I took Rad's advise and bought some break cleaner spray to use cleaning/clearing the tank vent tube and suggested he use it on his--just to make sure-- and his was clogged :blink: We looked a bit closer and found the orange rubber tit was off center, apparently it had been hit or something and was clogging the vent hose. Good thing we checked and found it, temp was about 100 here last Saturday, not good for a clogged tank vent, would suspect that could cause the tank to expand out of shape had the clog been complete, got it back in place and his line sprayed clear :yahoo:

 

[fJROB]

A friend came over last Friday and spent the night (wife was out of town) he just bought a used 05. I took Rad's advise and bought some break cleaner spray to use cleaning/clearing the tank vent tube and suggested he use it on his--just to make sure-- and his was clogged :blink: We looked a bit closer and found the orange rubber tit was off center, apparently it had been hit or something and was clogging the vent hose. Good thing we checked and found it, temp was about 100 here last Saturday, not good for a clogged tank vent, would suspect that could cause the tank to expand out of shape had the clog been complete, got it back in place and his line sprayed clear :yahoo:

The tank won't expand it will contract! I had my little orange vent seal swell up and pop out of it's hole, it was sitting on its side, when the cap got closed, it completely sealed the vent. while riding I felt a thump in the tank, when I stopped for fuel I could not get the cap off. I finally got the cap off and "whoosh" the tank had a tremendous vacuum built up in it and it would not take the usual amount of fuel. I ended up getting a new tank from Yamaha because the tank was buckled in the middle underside of the tank.

the moral of the story is to keep an eye on your little orange vent seal!

 

[jestal]

The tank can either build pressure or develop a vacuum depending on the conditions. You cannot say that it will always do one or the other. If it is cool and the vent is plugged and the tank is slowly emptied then a vacuum can develop. If it is hot and the heat and return fuel create a lot of vapor then pressure can develop. Keeping the vent line open and the orange rubber grommet in position will help minimize either occurance.

Fuel tank vents are designed to handle both vacuum and pressure to keep either at a manageable level.

The vacuum on the evaporative emissions system is used to pull fresh air thru the emissions canister. It does not act on the fuel tank itself so no vaccum develops in the tank due to engine vacuum. The canister is full of activated charcoal that absorbs the HC vapor as the tank vents and then the engine vaccum pulls fresh air thru the canister to pull the HC off and into the engine where it is burned with the normal fuel.

When the tank is hot more vapor is generated. Typically, the system is set up so that there is a certain level of pressure developed in the tank when this happens to keep vapor generation to a minimum. The vapor flow to the canister is controlled to prevent overwhelming the canister.

 

[fJROB]

The tank can either build pressure or develop a vacuum depending on the conditions. You cannot say that it will always do one or the other. If it is cool and the vent is plugged and the tank is slowly emptied then a vacuum can develop. If it is hot and the heat and return fuel create a lot of vapor then pressure can develop. Keeping the vent line open and the orange rubber grommet in position will help minimize either occurance.
Fuel tank vents are designed to handle both vacuum and pressure to keep either at a manageable level.

The vacuum on the evaporative emissions system is used to pull fresh air thru the emissions canister. It does not act on the fuel tank itself so no vaccum develops in the tank due to engine vacuum. The canister is full of activated charcoal that absorbs the HC vapor as the tank vents and then the engine vaccum pulls fresh air thru the canister to pull the HC off and into the engine where it is burned with the normal fuel.

When the tank is hot more vapor is generated. Typically, the system is set up so that there is a certain level of pressure developed in the tank when this happens to keep vapor generation to a minimum. The vapor flow to the canister is controlled to prevent overwhelming the canister.

The vacuum that destroyed my fuel tank was created from the fuel pump sucking on a sealed fuel tank, that was caused by the orange seal blocking the vent.

 

[ECDriver]

I live in AZ and its happened twice, both times air temp was above 108 degrees, tank level was down to 2 bars, running highway speeds, (80-85).

Pulled in to the station for gas, shut her down, opened the fill cap and hear this low rumbling sound coming from the tank. Pulled out the trusty mined approved (sparkproof) flashlight and sure enough, the fuel I can see is doing the slow boil!

Vent system works fine, won't prevent boiling, thats a temp issue not pressure.

So, to answer your question, yep, 05's will boil if tank is low enough and the temp from below is high enough. The cure for me is don't let the tank get below half if running hard or above 105. below 100 I have not had a boil yet.

Oh yea, one time I made the mistake of having 2 quarters in my front pants pocket, had two nice sunburn type red circles on my inner leg.

Dan