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Discussion Starter #1
Hey Guys,

I took the charcoal canester off my B3 800 and plugged my vac line. Had the bike in for its first service and the techs mentioned they needed to re-route the orphaned vac line. According to them, blocking it off isn't good enough and it needs to be open.

They ran it to my airbox so it could get clean air and wouldn't have to be plugged. has any one ever heard of this? It seems like a few members here just have them blocked...
 

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If you are talking about the purge hose from the canister to the intake tracts, that must be blocked off. You will have a major air leak if you don't.
The vent hose from the cap (which used to go to the canister) must be open to air. The old hose to just the canister was fresh air into can. Canisters inside the tank have this hose going to an external port in the tank which must be plugged or you have gas running out.

Not sure the F3-B3 set-up, but any hose(s) from canister to intakes must be plugged.
 

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Discussion Starter #3
Thats exactly what I thought and had done, but the techs had said it feeds to the intake and that it could cause issue? I'm not 100% sold on what they told me but I will monitor how the bike runs. They did leave the vent hose open as it vents the gas tank, but as I said they rerouted and unblocked the vacuum line that feeds to intake.

What are the ramifications on leaving this vacuum line un-plugged and routed to my airbox? any symptoms I should watch out for?
 

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They have no idea how the system works.....plug the hoses going to the intake tracts...that is nothing but an air leak causing a lean condition if the canister is not connected.

Tell them to go back to school.
 

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Discussion Starter #5
So I took a second look at my charcoal canister (good thing I kept it). I wanted to see how the air flowed through it and where the check valves were.

Interestingly enough, there is an open nipple on the bottom of the canister that is always allowing air in through the vacuum line. There is a check valve on the vacuum line, and the fuel vent seems to have a pressure valve and needs a few PSI to actually allow air through. the bottom one is wide open so I believe my dealership might actually be right about this.
Image below shows what i'm talking about
 

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The can is always open to fresh air. That's the inlet to let air in to replace the gas going out. The pressure valve is where the gas cap vents fuel vapors into the canister as the expanding evaporating gas in the tank raises internal pressure. The check valve on the vacuum side to the throttle bodies is to prevent air flow until there is vapor in the can to vent.
Trust me on this one ..... Gas cap vent to open air. Throttle body hoses from now removed can plugged off.
 

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They have no idea how the system works.....plug the hoses going to the intake tracts...that is nothing but an air leak causing a lean condition if the canister is not connected.

Tell them to go back to school.
yes +10
 

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What is this where is this and what does it????
You do not have this....it is an emissions device mandated by the state of California in the USA. Fuel vapor from the fuel tank vent are captured and fed into the intake tract to be burned, rather then vented into the air where it could contribute to smog.

It is impractical for MV to build 2 different spec bikes for the USA market (although the Japanese do). Most European bikes have just the one USA spec bike, and they all have the evaporative emissions system so they can be sold in California.
 

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When I had my 800 in for it's break in service, they toldme with the new update to the software, removing the carbon canister would cause all kinds of issues. Any truth to this?
 

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When I had my 800 in for it's break in service, they told me with the new update to the software, removing the carbon canister would cause all kinds of issues. Any truth to this?
Unless there is an ECM activated purge valve solenoid that will be removed and cause fault codes....NO.

Since only US models have this device, I seriously doubt that statement....very seriously doubt it. I suspect they do not even understand what it does or how it works.

They don't know what they are talking about.....if you live in Kalifornia then they may be worried about getting in trouble for "Tampering" with an emissions device if they take it off for you (a $40,000 fine for each offense)...but they would have to be pretty paranoid to think CARB is going to come looking and find out.
 

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When I had my 800 in for it's break in service, they toldme with the new update to the software, removing the carbon canister would cause all kinds of issues. Any truth to this?
My dealer said the same thing. I've been complaining about my F3 675 stalling/rough idle etcetera since day one. After this latest incident following the map update, (back on July 24) the mechanic was emphatic that if I'd touched the canister then I had caused a vacuum leak.
It doesn't matter if the canister does or does not effect anything. The point is the dealers believe it does and therefore if it's tampered with that is what they focus on first! So my advice is that as long as we here in North America have warranty on our bikes we should not mess with the canister.
 

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My dealer said the same thing. I've been complaining about my F3 675 stalling/rough idle etcetera since day one. After this latest incident following the map update, (back on July 24) the mechanic was emphatic that if I'd touched the canister then I had caused a vacuum leak.
It doesn't matter if the canister does or does not effect anything. The point is the dealers believe it does and therefore if it's tampered with that is what they focus on first! So my advice is that as long as we here in North America have warranty on our bikes we should not mess with the canister.
If you don't cap the canister lines to the intake tracts when you remove the canister then you do have an air leak. A big one.
What your dealer's techs told you is just what the technicians at one dealer told another member when he removed his canister...then they actually removed the caps he had installed!!! (there is another thread on this topic)

These techs have no familiarity with the CARB mandated EVAP systems and don't know what they are talking about.

The evap cans have been on "California only" models from every manufacturer for years, and are becoming more and more standard on all North American models as the manufacturers find it less cost affective to offer both "California only" and "Others" models.

MV has included the evap can on all USA models since the very first F4 because it made no sense to try and produce 2 separate models for the USA market alone.

Tell these guys they need to get some training. Regardless of how long they have been working on motorcycles, they are out of date on their technical knowledge.
 

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Discussion Starter #15
If you don't cap the canister lines to the intake tracts when you remove the canister then you do have an air leak. A big one.
What your dealer's techs told you is just what the technicians at one dealer told another member when he removed his canister...then they actually removed the caps he had installed!!! (there is another thread on this topic)

These techs have no familiarity with the CARB mandated EVAP systems and don't know what they are talking about.

The evap cans have been on "California only" models from every manufacturer for years, and are becoming more and more standard on all North American models as the manufacturers find it less cost affective to offer both "California only" and "Others" models.

MV has included the evap can on all USA models since the very first F4 because it made no sense to try and produce 2 separate models for the USA market alone.

Tell these guys they need to get some training. Regardless of how long they have been working on motorcycles, they are out of date on their technical knowledge.

I'm still a bit torn on this one though. I ran it plugged for a while until my dealership changed it. I'm a bit wary of going against what they do lest they use it as an excuse to deny me a warranty claim down the road. I haven't seen any difference in either configuration as well.

I did take the time to check out the charcoal canister and how air flows through it. What I found is that the air line to the intake is open all the time. Meaning it is always pulling air in. The gas tank vent has a check valve to prevent backpressure but the other 2 are wide open. When I spoke to the guys at the dealership they said plugging it will only make your bike run slightly rich which won't have any noticeable effect. I would assume better to run rich than lean, but better to run as designed than rich...

I did at one point try reaching out to MV Agusta but their response was that they don't recommend removing the charcoal canister due to local regulations...
 

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They have to tell you not to remove it. Removing it is considered "tampering with an emissions device" by the EPA and CARB in California.
They can be fined big bucks and get into all kinds of government trouble if the EPA found out they told you it is OK to remove it.

Dealerships and their technicians are in the same boat, although very few have actually been prosecuted. The EPA/CARB have bigger fish to fry. That said, DynoJet-PowerCommander got fined millions for selling their product in California a few years ago and not specifying "Closed Course Competition Use Only". Now they sell a "Race" version and a "California Legal" non-adjustable version for street bikes.

All the Carbon Canister Evap systems on bikes work basically the same way. The differences have to do with more modern ECUs controlling a "purge" valve to dump the fumes into the intake, and older tech models using simple intake vacuum all the time. (My 2008 Euro3 Brutale 910R had a ECU controlled solenoid valve which I simply unplugged since the "kit" ECU doesn't control it anyway).

You will not find Evap systems on the non-USA (North America now, it seems) MV Agustas. What you will see is the tubes from the intake tracts capped off. Those tubes are used to connect vacuum gauges (or carb sticks, etc) when you synchronize the throttle bodies.

I have attached a PDF file diagram of a basic evap system.

Here's how it works:
The canister vents to atmosphere.
The fuel tank can draw air through this vent, and though the charcoal, into the tank to compensate for fuel consumption from use or shrinkage from cooling.
The fuel tank will vent any pressure build up from refilling or heat expansion, and associated hydro carbon vapors from the fuel, into the charcoal.
The charcoal absorbs the hydrocarbon vapors before allowing the pressure to escape from the canister into the atmosphere.
The one way valves prevent raw fuel from entering the canister from the tank (sort of a roll over valve).
The canister vents from the bottom into the intake tract allowing the HC vapors to be drawn out of the charcoal and burned.
A purge valve allows the intake to draw vapors from the canister only under sufficient vacuum when the engine can consume the vapor without affecting fuel mixture.
Electronically controlled purge valves are opened by the ECM when the intake manifold pressure signal (or other sensor) indicates the engine can accept the HC vapors without affecting mixture.
(The drawing I attached is for a carbureted bike and the IAP sensor and vacuum damper is not related to the evap system, The purge valve operates strictly on high intake vacuum (low pressure.)

So you see, If you simply open the vent hose from the fuel tank to atmosphere the tank will vent properly, but any HC vapors will add to the local air pollution.
And if you simply plug off the hoses going to the intake manifolds the engine will never see the occasional small dose of HC Vapors during high load conditions. Those venting HC vapors, by the way, are NOT enough to change fuel mixture significantly, unless dumped in under low load or air flow (idle).

Please read the information at the top of the page I attached with the diagram. This will explain why you are getting the "do not remove" from MV and the dealers....but if you HAVE removed the canister you had best plug those intake hoses unless you like a big air leak and screwed up fuel mixtures (driving that 02 sensor wild at low speeds where it is working).
 

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Reviving this thread.

I've taken the two tubes off the cannister, left one open, and pinched the other off. I was having a tank venting issue - tank sucking in - and figured it was the evap cannister.

Since doing this I've not had a tank problem but the bike is running rough at low rpms, at low speeds, and has stalled a couple times ... a first for the bike.

Could it be that air is still leaking through the intake tube? I simply doubled the tube and pinched it off with a zip vs silicone sealing because I was just experimenting because I might need to take the bike to the dealer and I'm not keen to give the dealer any reason to dick around with warranty.
 

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I need to study the evap system on the 3 cylinder bikes (guess I should visit Donsy's site).
The bottom line though is you must locate the hoses that vented the evap can into the intake tracts and plug them.
 

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If fresh air enters the evap can, how does that not eventually lead to un-filtered air being fed to the engine? Based on the diagram it seems like the dealer that fchan spoke to was trying to mimic the stock setup with the evap can. I would be curious though how they routed the line to the airbox in a non-invasive manner.

Has it been confirmed that on EU models, the throttle bodies are simply capped where the North American purge hose feeds to?
 
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