Fuel tank breather 1125r

[paul.berry]

Hi there,
Just wondering if anyone has successfully stopped their fuel tank breather dripping fuel out & if so how?
I've tried secondary filter breathers to atmosphere which eventually soak & drip.
I'm now making a small charcoal drip tank that I can empty when necessary, it also vents to atmosphere & I may fit a filter breather on the end as well. Just finished it so no results as yet but hoping it will work.
Anyone else done anything different that has worked or is a work in progress?
Thanks folks.

 

[34nineteen]

Hi there,
Just wondering if anyone has successfully stopped their fuel tank breather dripping fuel out & if so how?
I've tried secondary filter breathers to atmosphere which eventually soak & drip.
I'm now making a small charcoal drip tank that I can empty when necessary, it also vents to atmosphere & I may fit a filter breather on the end as well. Just finished it so no results as yet but hoping it will work.
Anyone else done anything different that has worked or is a work in progress?
Thanks folks.

So, you're making a breather to fit a tank that is receiving fuel from another breather from another tank?

 

[Cooter]

He's making a reservoir for fuel vapor, silly.

IMO, I'd let it drip. Or put it on a rear stand. That stock vent is only open when the bike is on the side stand.

If you can't deal with that, use the charcoal can set-up you already have... and put a hose from it to a 'ported' vacuum source at the TB. It will empty the fuel vapors from your charcoal can for you. No more draining.

 

[34nineteen]

I would add one more catch tank and breather for good measure.

 

[Cooter]

Like Christmas lights, just hang them all around the bike!

 

[paul.berry]

He's making a reservoir for fuel vapor, silly.

IMO, I'd let it drip. Or put it on a rear stand. That stock vent is only open when the bike is on the side stand.

If you can't deal with that, use the charcoal can set-up you already have... and put a hose from it to a 'ported' vacuum source at the TB. It will empty the fuel vapors from your charcoal can for you. No more draining.

Sorry but it doesn't make sense that the vent is only open on the side stand, how does the tank vent when the bikes running if that's the case?
I can deal with drips, just not under the rear wheel when I'm trail braking & hard left cornering, which is the reason for the vapour trap & for my doubt about the vent only being open on the side stand.
I don't fit stuff on my 1125r for the sake of it, the charcoal trap is a tiny 3" by 1" alloy container that fits under the seat, one pipe in & one out. It certainly isn't bling & weighs in at 10 grams with charcoal.
Thanks for the reply Cooter.

 

[34nineteen]

The vent tube should exit at your passenger peg mount, if I'm not mistaken (my 1125CR's did that).

If you are venting enough raw gasoline to cause a safety issue while riding, you have a much bigger problem. Do you have the insulation on the inside of the frame rail?

Even when I got my 1125's super hot to the point where I was boiling fuel in the tank, I would only get a few drips when I would shut it off and let it heat soak.

 

[Cooter]

The breather on your bike that leaks fuel now is for relieving pressure build-up in the tank. That overflow should NOT be dripping while under throttle, only after you shut the bike off, put it on the side stand, then it's doing it's job. 1125's are notorious for freaking people out. Gas is flammable ya know LOL.

There is a different valve in the gas cap that will bring in fresh air to replace the gas you're using while the bike is running.

Trailbraking is NOT done with the rear brake, unless you enjoy epic high sides... and a couple drips won't matter either Mr. Rossi

I "think" it's in this video, if not its in one of the NCCR workshop vids, find it yourself for proof if you wish...
https://www.youtube.com/watch?v=DuHWLUIUiiA&t=945s

 

[paul.berry]

The vent tube should exit at your passenger peg mount, if I'm not mistaken (my 1125CR's did that).

If you are venting enough raw gasoline to cause a safety issue while riding, you have a much bigger problem. Do you have the insulation on the inside of the frame rail?

Even when I got my 1125's super hot to the point where I was boiling fuel in the tank, I would only get a few drips when I would shut it off and let it heat soak.

Hi 34nineteen,
I have 2 1125r's both are insulated with an extra fan, both tuned ECUs, airboxes, stacks & exhausts, both run under 87 degrees all the time & both have the venting problem.
I use one of them at Santa Pod & the fuel drip is a particular issue for this.
The problem seems to be that everyone thinks they only drip when they're hot & parked, in reality that's the only time I see it but they are venting all the time especially when hot & when the fuel is being tossed around in the frame whilst riding.
The vent tube standard does exit at the left foot peg which explains why the fuel ends up under the rear tyre.
Don't get me wrong here, it isn't pissing out, it's just the odd drip or splatter but enough to lose grip, especially on spirited down hill lefties.
I just wondered if anyone had successfully dealt with this issue but seems people don't have an issue with it.
Anyway, I'm hoping this little charcoal laden canister (third serious attempt at dealing with this) will soak up any gas for the time being & may give me an indication of just how much actually leaks during a ride.
Can keep folks informed if you want?
Otherwise thanks for your reply. You take care now.

 

[34nineteen]

Is the fuel boiling?
Are you overfilling the fuel tank?
Have you checked the operation of the fuel tank vent valve?
Is the bike overheating?

Any container of hot fuel is going to build pressure and need a place to vent that pressure to. Why not just reroute the vent house further back on the bike so any drops that are expelled are left behind you? Or just do your elaborate system of charcoal filters and catch cans. After all of the mods you said you have done to the bike; this should be easy.

Have you actually measured the amount of fuel leaking from the hose while riding or just making an assumption? How hard are you leaning this in the turns where a drop of gas is enough to spell certain doom?

 

[paul.berry]

Hi Cooter,
Firstly Great Videos links to NCCR & really interesting. Thanks for those.
I'm assuming that you still don't think the tank vents whilst riding despite the fact that pressure builds all the time the petrol is moving about & also think that the the ball in the relief valve only works whilst parked?
I can assure you this is not the case on either of my 1125r's.
I am aware that trail braking is done with the front brake & this is the reason why the fuel gets pushed to the front of the frame & the vent especially on downhill lefties like I said. A couple of drips of fuel in my case at least can be the difference in a critical line on a bend & that does matter a lot to me.
Mr Rossi I ain't by any means but I do like riding my 1125r to it's potential without unwanted hazards.
Thanks for the video links & your reply I appreciate the input.

 

[paul.berry]

Is the fuel boiling?
Are you overfilling the fuel tank?
Have you checked the operation of the fuel tank vent valve?
Is the bike overheating?

Any container of hot fuel is going to build pressure and need a place to vent that pressure to. Why not just reroute the vent house further back on the bike so any drops that are expelled are left behind you? Or just do your elaborate system of charcoal filters and catch cans. After all of the mods you said you have done to the bike; this should be easy.

Have you actually measured the amount of fuel leaking from the hose while riding or just making an assumption? How hard are you leaning this in the turns where a drop of gas is enough to spell certain doom?

Hi 34nineteen,
No the fuel never boils, I have the heat under control 87 degrees max, I have to use the spare fan in traffic to maintain that but otherwise the bike runs at around 76/80 on motorway/A road runs.
Fuel vent works as it should.
I'm in the process of measuring how much get's vented, I made the little catch can yesterday & working out the best place to fit it today so will know an average in the next week or so.
I tried vacuum venting like Cooter suggested but found fuel in the air box bottom so there's too much to vent successfully that way, although this will help at a later date.
Thanks for your reply, any input helps.

 

[Cooter]

If you vented it the way I described you couldn't have fuel in the air box. Run your charcoal canister air vent line to a 'ported' vacuum source. Ported vacuum only operates off-idle so you engine can deal with ingesting the extra fuel vapors and won't affect idle mixture.

It's exactly how a charcoal canister is supposed to be plumbed.

 

[paul.berry]

Hi Cooter,
Yeah I know the theoretical answers,they weren't what I requested..
To be honest I asked if anyone had done this or tried it on an 1125r. You obviously haven't or you wouldn't be quoting theories at me. Also the fact that you said the vent only works on the side stand tells me you don't really know FA about what I asked other than theory. Anyone can read theories, doing the job is different & theories are just that, theories.
But thanks anyway.

 

[Cooter]

Hi Cooter,
Yeah I know the theoretical answers,they weren't what I requested..
To be honest I asked if anyone had done this or tried it on an 1125r. You obviously haven't or you wouldn't be quoting theories at me. Also the fact that you said the vent only works on the side stand tells me you don't really know FA about what I asked other than theory. Anyone can read theories, doing the job is different & theories are just that, theories.
But thanks anyway.

I have had that breather apart and in my hand. Have you?

And it isn't any "theory" that engine vacuum will pull gas vapors out of your charcoal can. It is exactly how they function in any factory emissions system. Including California Buells, including every EBR.

NOT just sticking a hose in the airbox, you muffin... thats called a vapor BOMB:hororr:

put a hose from it to a 'ported' vacuum source at the TB.

and it is how you solve your worry that one drip from a vent tube will send you off in the dirt while "theoretically" dragging your elbow, inside passing that annoying Marquez.

Wow. Helping people who ask for help is getting more difficult these days.

 

[Cooter]

 

[34nineteen]

Hey Cooter,

Next time you need to give a precise, direct answer to peoples issues. Your theories are worthless and unwarranted. You probably havent even owned an 1125 or have even done a track day. Unless you have the correct answer, please refrain from your asinine comments.

But thanks anyways!

PS. My dog was right, your kickstand does lean your bike more than you do.

 

[Cooter]

Hey Cooter,

Next time you need to give a precise, direct answer to peoples issues. Your theories are worthless and unwarranted. You probably havent even owned an 1125 or have even done a track day. Unless you have the correct answer, please refrain from your asinine comments.

But thanks anyways!

PS. My dog was right, your kickstand does lean your bike more than you do.

My girlfriend leans harder than this tool does.

 

[34nineteen]

Oh noes!!! Cooters gonna crash!!!!

 

[Cooter]

You owe me a keyboard. Because theres coffee all over mine.




And there's an STD joke in there somewhere??:upset: