FE/FC Gas bath

I did my first race on the new bike. Worked awesome. Except, since it is a new bike I wasnt too worried about making sure it was running right before the race. So about 10 minutes to my start I get on it and hit the start button and NOTHING. I hit it at least 15 times and zippo. No kickstart on this bike either. So I tried to bump start it and it didnt fire, so I hit the start button and it lit right up. Dont know, was fine the rest of the day.

At the halfway, gas stop, pulled in took off helmet and gloves, maybe 5 minutes passed and I took off the fuel cap to fill her up and gas sprayed out of the tank for at least 3-4 seconds. I mean it sprayed out a lot, and got all over my jersey and gloves and the bike. I jumped back, because the bike was hot. Luckily no fire. Later that day at home I washed the bike and noticed the white frame has turned yellow from where the vent tube connects to the head stay on down to the skid plate. It wont come off. After the race the bike had sat a while and cooled off I took off the cap and it was fine. I shake the cap and I hear something rattling inside there. Should there be a rattle??? Is there a fix for this?

Bike is awesome though.

There should not be any pressure in the tank... that's the reason for the vent on the cap.... What bike?

I'm pretty sure mine all rattle (KTM/Husky). Just the way the vent works I think. How much gas was in the tank when you took the cap off? Seems like quite a large opening for gas to spray out of. I'm stumped on the stain on the frame. Pressure build up in the tank would make make sense for the the gas bath, but that would mean no venting, so no fuel would be going through the vent line. Unless it was building pressure then releasing through it. I've had bikes vapor lock from a plugged breather than they don't run for to long. Pull the vent line off and make sure its clear, see if you can draw air through it when connected to the cap too.

2015 FE350. 5 hours on bike. I had just rode 30 some miles on a full tank so what ever was left after that is the amount of gas it had. I only put gas in it 1 other time and it had been sitting, so this was the first time riding it and then putting gas in it right away. I am sure it had to be because of no venting, that is why I asked about the rattle. I bet it didnt rattle when it was plugged. I dont know. The stained paint just pisses me off. Brand new bike. I got some of it off with carb cleaner but didnt want to get carried away.

I thought I read some where on here, where guys were having the same issue but i searched and couldnt find anything thats why I posted. Also the bike was running great all day so I dont think vapor lock was a issue.

So does your cap one of those little caps on the breather line or does it go to the frame? Blow throw the vent line and see if you get flow

Take your gas cap inline check valve and toss it as far as you can. Next either get one of those tiny aluminum hose cap or route the hose to the fitting on the frame. NO bike should leave the dealership with this inline check valve.

https://www.rockymountainatvmc.com/...-Factory-Fuel-Tank-Cap-Vent?term=gas cap vent

I never had luck with them little short ones. Tried it on my sx and with a full tank it would spill on the tank. Where is the check valve? In the cap itself?

No I believe its in the line ususally 2-3 inches up and little plastic deal....

Hose between the cap and the frame. No luck with the tiny cap then let the gas spill into the frame.

It's a ball bearing type valve in the cap isn't it. Sits down til pressure forces it up n releases.

Jus run a long breather down under the engine along with coolant overflow problem solved

Gas tanks need to breathe in AND OUT. those stupid one-way valve things fu*k things up. I've seen people over-pressurize their tank by filling up with cool gas, putting the cap on and letting it sit in the warm air with the sun shinning on it. or doing this while the bike is in the back of the truck- and then driving 2000' higher. last week at Stonyford, my buddy did this; it popped his vent line off. thankfully, he believed my explanation; so I converted another.



About 10 years ago, a guy in Arizona had his gas tank SPILT in two- because he filled it up in the cool morning with cool gas and then put it in the garage (summer time). It was probably 130° in there (and 25+psi) by the time the gas tank let go. he never accepted the fact that it was his one-way vent valve ("...everybody uses 'em." uh, not really- no pro's do, of course)

if you see a carb that leaks when the bike is not being ridden.... turn the gas off, and crack the cap.

as gasoline warms up, it's liquid volume expands. but also, the vapor pressure increases too. it gets "bigger" fast; so you gotta let the pressure out.

Well good thing you didn't get injured first off. One bonus from this event is your gas tank now has more capacity from being overheated and stretched out. Gotta think positive. Like mentioned, make sure your vent line is clear and has no obstructions and you'll be good to go.

The bike has the check valve in the cap not the hose, and the hose goes to the frame. Yea, good thoughts, I think I will take out that little ball. I am pretty sure what happened was it got stuck up in the vent hole. As new as it is I am pretty sure it wasnt the hose plugged. And I think I will try the short hose with the cap so it doesnt mess up the paint any more. I have used them in the past with no issues. As simple as it is sometimes a few others input and thoughts make it easier. Thanks

How do those short vented hoses stay on? Do ya glue em or r they jus a tight fit?

I suggested the long hose down to bash plate/bottom frame rails to save ya paint, prevent fuel goin everywhere if it expands(not issue with ktm into frame I guess but old husky into steering stem leaks onto fender n stains it!) n cos if u ever split a fuel line u have plenty of spare hose.

Check valve in cap??? Unless they changed it for 2016 there inline. They stay on with barbs. Never place the cap hose into the steering stem. Fuel will wash the grease away quickly if you like to fall!

The short hoses just slip on to a nipple. Probably barbed. I never had a issue with the one I had.