DIY: Charcoal Canister Removal on F800GS (with pictures!!)

There is just a nipple coming out of the tank.... The "tip over valve" Must be inside the tank....... Cause the hose to the "pressure vacuum valve" as you called it, mounts right up to said nipple on the tank..... Then after the "pressure/vacuum valve....it runs down to the CC ( on the bike that still have`em)........Then back out on the top of the CC to the purge valve, which as you correctly stated is controlled by the ecm....

Erling

Griz-
I think I'm sittin' pretty with the '11 post recall charcoal. I've had her peg-deep idling in a water filled rut while I waited for the convoy to get moving and suffered no ill effects.

I know I yanked it off the 1150gs to install the jesses and off the X to install the MSR.

It seems like it's out of the way and if it doesn't give me any flac it can save the planet.

Thanks - I have heard that the "tip over valve" is integrated into the filler neck assembly, so that all makes sense. In terms of the cracking gas tank issue: IF there is a correlation (I think there is) then the key is to remove the pressure-vacuum valve from the system.

I'm 110% up for saving the planet!

Some of us conspiracy theorists think the pressure-vacuum check valve (yes I did come up with that catchy name for it on my own) in the canister "system" might be responsible for tanks cracking.....

Bingo.......

Erling

I'm going to do exactly that this weekend. I've noticed that, despite removing the charcoal canister, I still have a vacuum in the tank quite often.


I wonder if, rather than the canister/valve creating too much pressure in the tank, the canister/valve are creating a vacuum in the tank, effectively pulling the liner from the outer part of the tank, causing the cracks?



Has anyone ever found a diagram for the tank venting system BMW uses outside of the US??

I have not seen one..... But when I removed my CC....I found this little valve annoying. It vents quite fine inwards to the tank.... ( at least mine did)..... But it took about 5 psi for it to vent slowwwwwwwwlyyyy away from the tank..... Yet again.... If you applied a vacuum on the tank discharge side( against the arrow) it instantaneously opened up and vented away from the tank.....But if you just blew against the arrow......said 5 psi would purge it..... I have heard several people mention that that function is to prevent fuel from entering the CC..... I personally don`t think that valve is a necessity. I think it is plausible that if you constant have a vacuum in the tank......It could disfigure and subsequently crack the outer shell. My tank have never had any vacuum..... My tank have not has any cracking. Very hot desert sun.....and `09 with 6000 miles on it....

Erling

Here is the Euro bike parts diagram. I recently dropped my tank and the number 18 hose ran somewhere up front near the engine. I can take a closer look if it helps?

Thanks Lukas!!

I found the part nos for parts 15 and 17 and then compared them to the parts on the US bikes. SAME PARTS.

17 is a Ventilation Valve 16 11 7 721 943

15 is a Connection Piece 61 66 1 382 908

The difference is that in the US hose 18 goes to the charcoal canister, while in Europe it goes . . .? Out the bottom of the bike I would presume.


Lukas, do you ever have a vacuum in your tank, when you open it air sucks in?

Thanks!

Ahhhhhhhh it looks like #3 / #5 is the tip-over valve & vent line and that we should be able to "recreate" a Euro-equal bike by just dumping everything after the tip-over valve and running a small vent line down low on the bike somewhere!

Many thanks!

Or.... Since it serve as inflow to the tank......replacing air created by the vacuum.... you might wanna consider a filter......This is what I did...





Erling

Looks like you used the same filter I did. I can tell you that I'm glad I did. After about 8,000 miles, the filter is coated in dust. I'm actually going to clean it this weekend.

Nice......... Yep... It could make a mess if you don`t mount a filter.....Since the CC act as a filter...without one...You would get a lot of gunk in the tank....FI pump...injectors...etc....

Erling

Don't most motorcycle tanks vent to atmosphere? Does the Euro version connect to the airbox?

David

What model # is that Uni USA filter?

Where did you get it?

How much?

Yes. However, the BMW also sucks air back into the tank. I have no idea if other bikes do that too.

No idea what model number. I just went to my local dirt bike shop and they had a bunch of them on the wall. I chose the one that fit the vent hose.

Mine is from Autozone..... O`reily has them as well...... Spectra is the brand...
http://www.autozone.com/autozone/ac...25xh?itemIdentifier=266497&_requestid=2618784



Erling

Yes, historically, the gas tank pressure relief opening on motorcycle gas tanks vents out to the atmosphere via a hose. However, refer to post #17 for an explanation as to why the US EPA has nixed the "out-straight-to-the-atmosphere" design: http://www.advrider.com/forums/showpost.php?p=15300454&postcount=17

It is important to understand here that the F800GS gas tank design, as far as venting out and sucking in goes, is no different than any other motorcycle (on a BASIC level, so no need for brainiacs here). The F800GS tank vents out and sucks in when necessary, just like a 1987 KLR650 gas tank vents out and sucks in when necessary. Regardless of whether we're talking about a carbeurated 1987 KLR650 or fuel injected 2011 F800GS, both of these bikes vent out when pressure becomes too high inside the tank. They both also suck air in to replace the fuel that gets used by the carbs and engine. It's a back and forth suck/blow () scenario, and which one the tank does depends completely on many factors: atmospheric pressure, temperature, humidity, and how much the fuel level in the tank is dropping.

PS...I personally do not subscribe to the belief that +/- 5 PSI could actually expand and contract the red THICK inner bladder on this bike enough to crack the tank's outer, much more pliable black shell. It's just not enough force. And besides, I was able to inspect the first cracked tank that was taken off of my bike at the dealer. The outer black plastic shell is pliable enough to be able to withstand a decent amount of flex. Also, it would take a lot more than 5 PSI to expand and contract the thick red inner bladder enough in order to inflict enough pressure or force on the outer shell to crack it. It's just not possible. I had the tank in my hands and thoroughly inspected it.

Outer black plastic cosmetic shell: Thin, pliable, soft plastic.

Inner red gasoline bladder: Very thick, very stiff, hard plastic.... as in not expandable.

I'm not thinking about the environmental impacts of this modification.

What I was thinking, was the need for filters or hose routing. It seems like most bikes don't use anything very fancy.



Just thinking things through so I don't miss someting.

The F8GS does have fuel pumps and FI so clean fuel is important I guess.

David