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Discussion Starter #1
Today I was out riding in the city on my F4rr and when I pulled over to get fuel I noticed a large gap between my fuel tank and airbox. When I opened the tank I got an abnormally large release of air pressure and the gap immediately went back to normal. Later on that evening it happened again but this time when I opened the cap fuel blew out like a geyser since it had more fuel in it this time. Again the gap that preceded me opening went away.

I'm sure it can't be too hard for the people here to let me know what to look for. I was thinking maybe a blocked or pinched breather hose or something. Any suggestions are welcome.

Thanks,
DJ
 

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Look under the rear of the tank. There are two hoses that come out, wye together and then run down the left side of the engine to the ground.

Make sure that path is not blocked or kinked.

What is the last thing done to the bike before the issue arose?
 

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Discussion Starter #3
Hoping to look at it closely today but decided to remove some fairings in the meantime. I noticed that my coolant bottle is really low. Not sure if that is related or not. The bike didn't seem to be overheating but maybe running a little hotter around town than normal.
The last thing I had done to the bike was install a QD slip-on exhaust.

Thanks for the help,
DJ
 

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The coolant level should be low in the bottle.

Installing a QD slip-on should not have an effect on the tank vent.

Again, I would check the tank drain and vent lines to ensure they are not pinched or fouled.

Have you removed your tank for anything recently?
 

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Discussion Starter #5
Sorry for the delay in replying but I was away at work for the past two weeks and haven't been able to look at it.
So I hadn't had the tank off before. I checked the vent line today that runs to the small hole under the gas cap. I blew air into the hole and was able to feel air coming out of the hose that exits on the left side of the bike. I'm sure what other lines I should check.
I don't know if it would cause it but the bike was low on coolant. I haven't had the fairing off the bike for a bit and realized later that the coolant bottle looked practically empty. I have topped it up but haven't been out with it since.

Do you think low coolant could be a cause? I only had the problem running around the city and not on the highway.
I am also concerned as to why my coolant has gotten so low as well. I may have the dealer look into it but I'm trying to save myself some money by being able to point them in the right direction.

Thanks,
DJ
 

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??????

DON'T FILL THE COOLANT TANK ABOVE THE "MIN" MARK !!!!!!!

It will just piss it out in front of YOUR back tire in left turns

If you have a MicroTec or remapped ECU set to turn the fans on at 85C/185F ignore this

:surprise:
 

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Sorry for the delay in replying but I was away at work for the past two weeks and haven't been able to look at it.
So I hadn't had the tank off before. I checked the vent line today that runs to the small hole under the gas cap. I blew air into the hole and was able to feel air coming out of the hose that exits on the left side of the bike. I'm sure what other lines I should check.
I don't know if it would cause it but the bike was low on coolant. I haven't had the fairing off the bike for a bit and realized later that the coolant bottle looked practically empty. I have topped it up but haven't been out with it since.

Do you think low coolant could be a cause? I only had the problem running around the city and not on the highway.
I am also concerned as to why my coolant has gotten so low as well. I may have the dealer look into it but I'm trying to save myself some money by being able to point them in the right direction.

Thanks,
DJ
You have checked the hoses are free,thats good.
Have you had a look at the fuel cap itself that it is venting?
 

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After a couple of tries by the dealer to fix the venting issue that is just like yours, they removed the canister. Problem solved.
 

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What canister did they remove?

On US bikes and probably Canadian too, there is a carbon canister located inside the tank next to the fuel pump. Remove it, hook the vent line directly to the fuel pump housing and Voila.
 

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Evaporative Emissions Carbon Cannister

@stickmandj: This is an ongoing problem we that try to help have within the forum...If we do not know the Year of your F4RR, or if we do not know the country in which you bike resides, it is difficult to accurately help.

After doing some sleuth work, I discern you are from Canada and you probably do not have a 2009 F4 1078RR (which was the original F4 1000 RR).

That being said, your bike is probably a US Spec model F4 1000 RR and it probably has the US Emissions required Carbon Cannister. This can resides in your fuel tank and is in direct line with your tank venting system.

F4 1000 Carbon Cannister.jpg
 

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It's a charcoal canister so my guess is it absorbs gases from the venting process or maybe even traps fuel that spills over at the cap or both. Not sure but I know once it was removed my venting issues went away. You could replace it if you think it's necessary but it is most certainly your issue.
 

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Discussion Starter #17
@stickmandj: This is an ongoing problem we that try to help have within the forum...If we do not know the Year of your F4RR, or if we do not know the country in which you bike resides, it is difficult to accurately help.

After doing some sleuth work, I discern you are from Canada and you probably do not have a 2009 F4 1078RR (which was the original F4 1000 RR).

That being said, your bike is probably a US Spec model F4 1000 RR and it probably has the US Emissions required Carbon Cannister. This can resides in your fuel tank and is in direct line with your tank venting system.

View attachment 389218
Apologies for the confusion. I just realized I didn't put that info in. So, yes I'm from Canada and the bike should be a US spec, 2016 F4RR.
 

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If you look at how the cannister is plumbed, it can cause issues if your tank is overfilled thus filling the charcoal with fuel, or by having it plumbed incorrectly.

The canister's purpose it to adsorb hydrocarbons before they evaporate into the atmosphere.
 

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Remembering that, if you do it incorrectly, you will cause poor running of your MV due to a vacuum leak.
 
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