[Tommy]

I'm aware that this is an old thread, but wanted to add some clarity in regards to the "fuel tank charge hose" (the thinner one) removal.

The other hose (thicker) is a liquid spill hose for the filling neck in case you get a bit overzealous in filling your tank, and overflow a bit, or a bit of rain water gets in there. The thicker hose does NOT connect to the inner part of the gas tank in any way.

Back to the "fuel tank charge hose". This hose in stock trim on USDM Groms will actually 'breathe' both ways if you let it. If you don't believe me, give it alternating pressure and vacuum and you'll see that air flows both ways.

Now, if you're doing this mod you have two choices: 1) leave the hose/tank stem as-is and allow your tank to openly vent if hot/pressured, and suck in air when vapors condense/fuel is consumed, or 2) add a valve (like the one MNNTHBX suggested) and allow your tank to take in air (and thereby prevent a tank vacuum - IMO the more important of the two functions on a fuel injected bike) but not allow those fumes to escape from evaporation, or in the event of the bike falling over, crashing, etc.

Considering the only apprehension in doing this mod, IMO, is that it would make your bike slightly more environmentally 'un-friendly', I opted for option #2.

 

[MV Agusta F3 800]

Deleted the entire evaporative emissions system today.

A thought...

Leaving the OEM tank vent hose (the small one attached to the nipple on the right side of the tank) routed as delivered (around to the left side of the tank), would prevent fuel spillage if the bike goes down on the right side.

 

[EddyMunsta]

Not gonna waste the time on this one, I get more of a weight reduction by taking a big deuce.

 

[srosamechanic]

The charcoal canister functions as follows: Fuel vapors and pressure build in the fuel tank. These vapors are vented into the charcoal canister (which filters the fuel from the air). The engine decides when to open the purge solenoid (usually under low load, high vacuum as in idle at stop or low RPM steady cruise)and adjusts the air fuel mix accordingly by slowing the injector pulse width. So... If you remove this, the ECU is still expecting the incoming fuel vapor when it says to open the purge valve, but alas a backyard mechanic has removed it because he's an "engerneer" and now the bike runs lean. So in short, leave it alone unless you switch to a euro spec ECU or tune it out. Any gain from weight savings ( none ) are immediately cancelled out as your bike will run hotter idling and steady cruise, causing burned valves and shortened engine life. these are not things that are seen in a couple hundred miles, but thousands. Then its bye bye motor. I am a 16yr ASE certified Auto and Motorcycle technician. There is nothing I like more than free horsepower or weight savings, but if you want a mod that will save weight and save you money, stop eating cheeseburgers. I didn't write this to insult anyone or call you out, but there seems to be lack of information and proper tech info on "mods" like these. I wanted to clear the air and inform those who ask the question "If you can get gains with no downside, why did Honda spend so much time and energy engineering this and producing these parts?". Please feel free to chime in or ask questions, but I will not respond if you're argumentative.

 

[Old Goat Ninja]

"If you can get gains with no downside, why did Honda spend so much time and energy engineering this and producing these parts?"

Because they have to meet emissions standards.

Anyways, I don't know if you are correct or not in everything else you said, but I do know that for a while, only California bikes had these canisters (not talking about the Grom, just bikes in general). Now they all do I think because it's easier to make one bike that different bikes for different markets.

 

[srosamechanic]

As I said before, taking it off is not the problem. You have to tune it out or replace ECU with euro spec (or whichever country doesn't use it). Honda (and anyone else that puts the canister on their bikes) designed and tuned the system to reduce the emissions with no downside. Win win. All it does is use the fuel stored in the canister vs injecting more, which pre-vaporized fuel mixes better with air than injected so if anything, there is slightly (doubt its any bit noticeable but nonetheless) more power with the canister than without.

 

[turpinator]

The real question is... How much fuel is this /really/ adding to the mixture when its pulling from the evap canister?

 

[srosamechanic]

That is a great question. In short, you would watch the air fuel ratio while it is attached (and the purge solenoid is active), then remove it and check the air fuel, then tune the ecu to add more fuel until the original A/F ratio is achieved. the amount you had to make up would be your answer. I no longer have a motorcycle dyno so I wont be able to tell you myself.

 

[LameDuck]

I am well aware this is an old thread, but i thought resurecting it would be better than starting a new one on the same subject. Wouldn't the ECU read the AFR from the O2 sensor and compensate for it, rather than run lean? Even if it didnt, would the lack of some vapor really effect ACF enough to make a difference that wasn't almost completely negligible anyway?

 

[turpinator]

I am well aware this is an old thread, but i thought resurecting it would be better than starting a new one on the same subject. Wouldn't the ECU read the AFR from the O2 sensor and compensate for it, rather than run lean? Even if it didnt, would the lack of some vapor really effect ACF enough to make a difference that wasn't almost completely negligible anyway?

bingo.

 

[farkas]

bingo.

But, but, but.... he's an ASE Certified Mechanic.... lol

 

[LameDuck]

So am I, amd his argument still makes no sense to me lol

 

[Pigman]

Cause he is wrong.....LOLOL. Doesn't affect the fuel imput at all

 

[Paultergeist]

The entire charcoal canister implementation has always seemed odd to me. In my line of work, we use activated charcoal sorbent media for purification of breathing air within industrial environments (such as painting shops) -- the idea is that the charcoal will remove some organics chemicals from the air (prior to that air then being breathed by a worker). My issue, however, is that the charcoal sorbent media will only adsorb a finite amount of chemical molecules -- once the sorbent has adsorbed all it can ("saturated") it will adsorb no more. This point of saturation does not take very long. Once saturated, the organic molecules are then only released from the sorbent with any efficiency by methods such as: translocation with another more avidly-bonding chemical molecule, a very strong vacuum, or high heat. In a nutshell: the sorbent media in the canister probably helps pass some initial emissions tests when the bike is brand new, but once the sorbent charcoal is saturated, I do not believe it does anything else -- it cannot adsorb any more. Once saturated with gasoline vapors, those molecules are extremely unlikely to be released in any coordinated manner on a motorcycle.

I have always found the notion that the charcoal canister somehow *saves / stores* gasoline vapors -- to then be magically released back into the intake due to throttle position or solenoid response -- to be in contradiction with what I have learned about the chemistry and thermodynamics of such things. Please enlighten me if I am incorrect on this point.

 

[phillybuilt]

The entire charcoal canister implementation has always seemed odd to me. In my line of work, we use activated charcoal sorbent media for purification of breathing air within industrial environments (such as painting shops) -- the idea is that the charcoal will remove some organics chemicals from the air (prior to that air then being breathed by a worker). My issue, however, is that the charcoal sorbent media will only adsorb a finite amount of chemical molecules -- once the sorbent has adsorbed all it can ("saturated") it will adsorb no more. This point of saturation does not take very long. Once saturated, the organic molecules are then only released from the sorbent with any efficiency by methods such as: translocation with another more avidly-bonding chemical molecule, a very strong vacuum, or high heat. In a nutshell: the sorbent media in the canister probably helps pass some initial emissions tests when the bike is brand new, but once the sorbent charcoal is saturated, I do not believe it does anything else -- it cannot adsorb any more. Once saturated with gasoline vapors, those molecules are extremely unlikely to be released in any coordinated manner on a motorcycle.

I have always found the notion that the charcoal canister somehow *saves / stores* gasoline vapors -- to then be magically released back into the intake due to throttle position or solenoid response -- to be in contradiction with what I have learned about the chemistry and thermodynamics of such things. Please enlighten me if I am incorrect on this point.

I will honestly say I don't know as much about the chemical composition of charcoal and how it works, first and foremost. I've worked with evaporate emissions systems for the past 11 years on cars of all types.

The idea of the system is to control excess fuel vapors, by a closed loop method which contains and then releases those vapors when the solenoid is activated, and can vent to the tube going to the intake manifold.

The charcoal canisters in your theory would be replaced really often if that is the case. Going back to your previous post, the fuel molecules are released from the sorbent by vacuum.

When I worked at Kia, we had issues with the optima's having the canister crack where it mounts, causing either small or large evaporate emissions leak codes. Those are really the main times they get replaced, when they cause leaks.

But just a thought - if the charcoal became useless that fast, knowing how greedy auto companies are, you don't think they would be trying to replace those at service intervals?

Sent from my HTC One A9 using Tapatalk

 

[ajbrooks1]

Does this apply to the 2018’s?

Sorry, new Grom owner!

 

[farkas]

Does this apply to the 2018’s?

Sorry, new Grom owner!

It applies to any Grom destined for US markets.. so, yes

 

[Paultergeist]

The idea of the system is to control excess fuel vapors, by a closed loop method which contains and then releases those vapors when the solenoid is activated, and can vent to the tube going to the intake manifold.

Yes, that is indeed the "theory." The *reality* is that the relatively weak vacuum produced by engine intake is not going to dislodge significant amounts of fuel molecules from he charcoal sorbent.

The charcoal canisters in your theory would be replaced really often if that is the case. Going back to your previous post, the fuel molecules are released from the sorbent by vacuum.

The evaporative canister is there because of a legal requirement imposed by the government in efforts to reduce smog. While the intentions may have been good, I am saying that the under-lying science behind this idea is flawed. Current emissions tests of such systems DO NOT confirm the sorbent's ability to first adsorb vapor molecules and then somehow conversely release those fuel molecules (as if, just because we wished it worked that way) -- the evaporative test is limited to confirming solenoid function and that the system will hold a vacuum.

Once that sorbent is saturated with fuel vapor molecules, it is done.

 

[S1930]

LOL, I love reading threads like this.

Short answer is that ALL new motorcycles that could be sold in the country of California have this charcoal canister. Period.

I removed this from my $22K Ducati just like I will from my Groms. It gives me more room to mount aftermarket parts (and saves weight on the grom). Also, note that old canisters on some motorcycles can suck charcoal back into the gas tank and really mess up your day. Ducati's are well known for having starting problems with older charcoal canisters. Remove the canister and no issues with starting (I think the 1198s were notorious for this).

You don't need the canister unless you have to pass inspections in California. Euro bikes don't even have this device.

 

[Pard]

do not cap the manifold line my throttle dropped after doin so and my bike stalled out

everything is open in the running state not closed

op should really revise this

a lot of wrong info in the first post

The charcoal canister functions as follows: Fuel vapors and pressure build in the fuel tank. These vapors are vented into the charcoal canister (which filters the fuel from the air). The engine decides when to open the purge solenoid (usually under low load, high vacuum as in idle at stop or low RPM steady cruise)and adjusts the air fuel mix accordingly by slowing the injector pulse width. So... If you remove this, the ECU is still expecting the incoming fuel vapor when it says to open the purge valve, but alas a backyard mechanic has removed it because he's an "engerneer" and now the bike runs lean. So in short, leave it alone unless you switch to a euro spec ECU or tune it out. Any gain from weight savings ( none ) are immediately cancelled out as your bike will run hotter idling and steady cruise, causing burned valves and shortened engine life. these are not things that are seen in a couple hundred miles, but thousands. Then its bye bye motor. I am a 16yr ASE certified Auto and Motorcycle technician. There is nothing I like more than free horsepower or weight savings, but if you want a mod that will save weight and save you money, stop eating cheeseburgers. I didn't write this to insult anyone or call you out, but there seems to be lack of information and proper tech info on "mods" like these. I wanted to clear the air and inform those who ask the question "If you can get gains with no downside, why did Honda spend so much time and energy engineering this and producing these parts?". Please feel free to chime in or ask questions, but I will not respond if you're argumentative.

Can someone check my work and make sure I did it correctly?

I am installing an Aracer mini 5 and a chimera intake tomorrow so I will tune for best fuel air mixture, eliminating the worry of the throttle body line to the canister cited above. Hence, I just capped it, item #2 in the picture.

#1 is the solenoid connector, vinyl tape to cover it and zip tied it out of the way.

#3 is the connection of the tank vent line using a run of plastic tubing.

Am I good to go? Bike starts up and runs fine with no check engine light.