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Fuel cap vent

W

willyweeman

Joined Dec 2011
14 Posts | 0+
Grand Junction Co.
Hi All,
Can anyone give me some input? I have a 2011 FE 570 and would like to remove smog canister and valve. What is the best way to vent the fuel cap?
 
I have the same bike. The way I did it was to install one of those vent cap valves on a little stalk of stiff tubing. There's a blue anodized "Fuel Tank Cap Vent" for $15.99 available from Husaberg, but I got one from Cycle Gear for maybe $10. It words fine, no issues, and the fuel cap doesn't dangle on a vent hose any more.

Note, the tubing used to install the vent is very, very stiff. You will have a terrible time trying to get it on the cap and valve nipples if you don't warm it up hot water.
 
I would recommend not to use a one way vent valve on the gas tank. I have heard too many horror stories of pressure buildup, flooding carbs, etc. Your best bet is to simply run a suitable length of tubing instead of the one way valve.
 
I'm carbed on my bike, but had a 4 month old check valve block up on me. Started hearing air escape when taking the cap off.

It's not a one way valve, it allows pressure to exit, but it got plugged.
When new I could blow air in, easier than out but after it become blocked only in.

I cut the old 3" line off, because i couldnt pull it off. I washed it in hot water and used a new short piece of hose.
Works fine now, like new.
 
Idle said:
I'm carbed on my bike, but had a 4 month old check valve block up on me. Started hearing air escape when taking the cap off.
Click to expand...

That's the whole idea of a check valve. The check valve allows air to enter but not to exit, thus leading to pressure buildup when the gas heats up.
 
Chas said:
Idle said:
I'm carbed on my bike, but had a 4 month old check valve block up on me. Started hearing air escape when taking the cap off.
Click to expand...

That's the whole idea of a check valve. The check valve allows air to enter but not to exit, thus leading to pressure buildup when the gas heats up.
Click to expand...

?

actually i think you'll find its to allow air in and not allow fuel out if you tip the bike on its side.

most of the time i bin the check valve and just pit on a longer piece of pipe which you can put a loop in to get the same effect. Also a simple piece of pipe wont go south
 
I loop them around the handle bar and up to the throttle where is zip tied, at the end is a filter for a pressure washer i got from the hardware store, its a 1cmx2cm cylinder filter with a 3/16 peice of brake line epoxy'd in so that it can be connected into the vent tube line. i used to always just loop them around the bar a couple time with nothing at the end, the filter thing just looks custom and cool it really doesnt need to be filtered or sealed, you can lay it on its sides and if fuel gets in there it evaporates out, ive never seen anything more than maybe a drip come out on a full tank and bike on its side, or for that matter even a drip in the looped portion of a clear hose, maybe im too busy rippin and just dont pay attention to a few drips of gas coming out or a few micro particles of dust in my fuel, ive never owned a efi bike.
 
Chas said:
Idle said:
I'm carbed on my bike, but had a 4 month old check valve block up on me. Started hearing air escape when taking the cap off.
Click to expand...

That's the whole idea of a check valve. The check valve allows air to enter but not to exit, thus leading to pressure buildup when the gas heats up.
Click to expand...

No, i don't think that's how fuel tank vents are designed.

I don't know who makes the one I have, I got it at the Honda shop. It's likely the same as all the other billet fuel vents.

I'm sure because when new, I checked it's operation. Air easily passes in if you blow on it. Turn it around and it's restricted enough to not allow much if any fuel out, but will allow air pressure to escape.

It has been fine since I've cleaned it. No pressure buildup and no fuel leaking when it's taking a nap.
 
These one way 'check' valves are designed to keep fuel in the tank. When they are working as designed, they keep fuel and also air from escaping hence the pressure buildup when things heat up.
 
they do keep air in if shut but this is as a result of the pressure building and closing the vent which then causes more pressure to build, they arent actually made with the idea of building up air pressure, its just a side effect.
 
cypher said:
they do keep air in if shut but this is as a result of the pressure building and closing the vent which then causes more pressure to build, they arent actually made with the idea of building up air pressure, its just a side effect.
Click to expand...

Exactly my point. That is why I suggested not to use one way check valves on the fuel tank in the first place.
 
obvioulsy been some crossed wires as in the post above you say;

"That's the whole idea of a check valve. The check valve allows air to enter but not to exit, thus leading to pressure buildup when the gas heats up. the idea of the check valve is to keep air in."

which i think every one has read as the check valve is there to keep the air in and thats what its designed to do.

oh well all sorted now
 
Yea! wrap it around the bars once or twice, tie it off whereever you like it, and do whatever you want cept put a valve on it!
 
My FUEL CAP VENT has three functions. Those of you who have a vent that allows pressure to build up have been shortchanged and should upgrade.

Function 1, allow air to enter tank as fuel is used.
2, keep fuel from spewing out when the bike is on it's side
3, allow air pressure to escape when the sun warms the tank and expands the air and or fuel.

It's clear that 1 and 2 work as designed. "3" is not an accident, I think it's designed like this as air is thinner than fuel and can escape through the vent whilst fuel can not.

#2 function splained;
I ride on 17" wheels off road and am new to dirt as of April. I've dropped it over a dozen times and fuel has never leaked out of the cap or vent.

#3 function splained;
If I blow in the tank through the vent hose and pressurize it and immediately open the cap I can hear the air
escape. If I pressurize it and wait 5 or ten seconds, and then open the cap I get no air escaping. (it's leaked out).

As I stated earlier, it quit working a few months ago and allowed pressure to build. I cleaned it and it's worked as
designed ever since.
 
willyweeman said:
Hi All,
Can anyone give me some input? I have a 2011 FE 570 and would like to remove smog canister and valve. What is the best way to vent the fuel cap?
Click to expand...

I don't know what the 2011 models have but my 2010 has this:
Fuel+Tank+Breather.JPG


The hose is just 1/4 inch ID
I purchased one of the blue anodized "Fuel Tank Cap Vent" things but they have a one way valve in them that wont let air out of the tank, as already mentioned in this post above. I never had the boiling fuel issue till I installed the blue anodized "Fuel Tank Cap Vent" thing. So I went back to 1/4 inch hose as per the picture.

The little plastic plug in the frame is:
51030022000 ANGLE PIECE 90 DEGREE M10X1 $3.38

Sorry for the delayed reply but I have been busy with lots of PM's :evil:
 
I have the same setup, connected to the frame om my 2010. This is good to keep the fuel away from your hot engine and pipe in case of a tip over.

To comment to all the other postings: I had a fuel injected enduro bike before. Running it on the dyno we had a power dip around 8.000 rpm. We searched and searched. Then the engineer had an idea: let's remove the fuel cap with this short one way valve.

And presto! It climbed through the power band like a wilde ape!! :cheers:
 
Okay, Noppy, that does it. I'm going to remove the valve from my fuel cap and just run a hose.
 
I ran a length of clear blue fuel line from the fuel cap to the steering head and zip-tied it in place. Good results. There is no hesitation to abrupt throttle inputs and it revs very happily.
Noppy, you're a genius!
 
Well, thank you indeed, no one has ever said that to me :lol:

At least, I didn't feel like one and still don't. That mechanic of mine, truely is a genius. Pity he is with Yoshimura/Suzuki :bounce3:
 
You're welcome, sir, and you need not be modest when the truth is involved!

There's an additional benefit in using clear fuel line over black rubber or the aftermarket check valve - you can see what's going on. I spent about an hour and a half on the 570 yesterday, and at the end of the ride there was a very small quantity of fuel (no more than a drop) visible in the clear fuel line just at the gas cap nipple. It's entirely normal of course, but I would not know that entirely normal was occuring with black rubber or the aftermarket check valve.
 

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