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Evap removal from V7III

Discussion in 'V7/V85/V9 Chat & Tech' started by Godfrey, Oct 17, 2017.

  1. JACoH

    JACoH Cruisin' Guzzisti

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    I got a batch of 10 on ebay for about $5, much better quality than stock. 5mm speed nuts... probably at better hardware/fastener shops, too.
     
  2. GuzziTex

    GuzziTex Just got it firing! GT Contributor

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    Thanks!
     
  3. Mayakovski

    Mayakovski High Miler GT Famiglia

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    Any update on this filter?
     
  4. BearV7

    BearV7 Just got it firing!

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    Also interested in this...
     
  5. BearV7

    BearV7 Just got it firing!

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    I love the GT tune (otherwise stock) and keep reading it works even better with the intake leak plugged so I want to try it, but the family wouldn't appreciate gas fumes in the garage so I'm thinking about doing this. Is the following process correct?

    1. Cut line between evap can and Y air intake. Put vacuum caps and clamps on both sides.
    2. Defeat the valve by either gutting it or replacing with inline fitting.
    Is that it? The air leak would be plugged, the tank pressure is relieved because the valve is gone, and the vapors/fuel get trapped by the evap can?

    Thanks! -B
     
  6. Godfrey

    Godfrey High Miler GT Famiglia

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    Follow up:

    My Racer's evap system has remained disabled exactly as I described at the head of this article for the past 2000 miles or more. It produces no gasoline fumes whatsoever, other than the miniscule whiff that occurs from fuel sloshing violently about in a nearly empty tank. It certainly doesn't produce any when just sitting in the garage.

    Next move will be to remove the evap canister entirely, as well as the line coming off the intake manifold, and plug the vacuum fitting on the manifold permanently. If I'm in a particularly caring mood, I'll fit a small K&N filter to the end of the tank vent hose to prevent the random speck of dust from going up into the tank. :D
     
    Last edited: May 29, 2018
    Mayakovski likes this.
  7. Richard Ducati

    Richard Ducati Tuned and Synch'ed

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    Godfrey,

    First and foremost, thanks for posting pics and writing up your canister removal blurb. I just got a GT tune from Todd and need to do this work. Like you, I'll probably just snip and plug the hose attached to the manifold vacuum port until I have better access to remove the system completely.

    In terms of the tank vapor vent, I'm struggling with why your machine would develop a vacuum on the tank side. Is there no other vacuum relief for the tank? The evap system has a check valve between the tank and evap canister, so there must be some sort of vacuum relief to relieve the vacuum developed due to fuel use (vented cap?). I was planning on just nipping off the hose at the canister outlet for now and removing the section between the canister and manifold, but will be more thorough if the check valve is an issue.

    Regards,

    --Rich
     
  8. Mayakovski

    Mayakovski High Miler GT Famiglia

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    Morning Rich;
    I believe if you search around this forum you will find a fair number of posts pointing to the check valve being garbage and failing. I think that is the reason for the vacuum issue in the tank. Gonna do this soon myself, I have the gear from Todd, just waiting for my bikes first service to be done.
    Ciao
    Maya
     
  9. Godfrey

    Godfrey High Miler GT Famiglia

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    Yes, it is the check valve itself that is at issue. That's why I blocked the vacuum tap and removed the check valve. The first eliminates a vacuum leak on the intake, the second allows the tank to vent properly.

    The EVAP system wouldn't function at all if there was a second vent on the tank. then you'd just have a vacuum leak. :)
     
    Tequilasunriser likes this.
  10. Richard Ducati

    Richard Ducati Tuned and Synch'ed

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    Understood. FWIW, I thought the evap system was just there to vent positive pressure from the tank due to fuel expansion & sending the vapors into the intake for burning, thus protecting us humans and other species inhabiting the planet from all those nasty fugitive emissions. In my little brain, the presence of the check valve between the tank and canister thwarts any thought that vacuum was to be relieved using this same system.

    Anyway, bottom line is that the check valve needs to fall off in order to ensure that the tank vacuum relief is fully functional....
     
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  11. Godfrey

    Godfrey High Miler GT Famiglia

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    Okay, perhaps a little context will make this clearer for you.

    The EVAPorative Emissions Control System (EVAP) is designed to prevent gasoline fumes from the evaporation of fuel in the tank from going to the atmosphere. EVAP systems should be totally passive and innocuous, similar to the Positive Crankcase Ventilation (PCV) systems that have been in place on most production engines since the 1950s.

    Basically, even when just sitting and doing nothing, fuel in a tank slowly evaporates and fills whatever space is in the tank with a small amount of vapor. For large fuel storage tanks, this can be explosive and very dangerous, not to mention costly if the fuel is vaporizing away unheeded, so they have extensive vapor circulation and recovery systems designed to recapture the fuel vapors and return them to the tank. In motor vehicles like motorcycles, automobiles and trucks, the amount of vapor loss is really quite small on a per machine basis, but given that it is still an output to the atmosphere that can be avoided pretty simply ... by routing it to the intake to be burned with combustion ... it seems simple enough to put a passive system in place to handle it. Automobiles and trucks typically spend a great deal of their time sitting parked, often out under the hot sun, between trips which exacerbates the evaporation problem.

    Fuel tanks also build a certain amount of negative pressure without venting while the machine is running (due to the fuel level being drawn off for the injection/carburetion), which creates MORE evaporative fumes to build up in the open air space of the tank. (...As atmospheric pressure goes down, more fuel molecules can escape the surface tension of the fluid body into the atmosphere...:))

    So the EVAP system's intent is to leverage the vacuum in the intake manifold to draw the fumes away from the tank while the engine is running by applying a small, persistent vacuum to the open space in the tank, and vent the fumes into the intake stream for burning.

    The purpose of the charcoal canister is to scrub any residual output of the tank's fumes, letting charcoal granules absorb them temporarily, while the machine is sitting still. (The flow of air through the canister during engine operation will be towards the intake plenum, because of the vacuum being applied, so the residual molecules are basically recovered and pushed back into the intake while the machine is running.)

    The purpose of the so-called "check valve" (it's not really, as should become clear) is to regulate the amount of vacuum being applied to the tank and make sure that the flow of gases is always in the direction of the intake plenum. So it's not really a "check valve" per se ... which is a one-way flow valve only ... but more of a very simple "vacuum regulator." It's supposed to not allow too much vacuum to be applied to the tank's air space, allowing atmosphere to enter the line between the tank and the valve when the vacuum being pulled by the intake plenum goes over a prescribed limit, while not letting positive pressure push fuel vapors out to the atmosphere.

    Too much vacuum in the fuel tank has two negative effects:
    • Fuel delivery is constrained, since too much vacuum in the tank is making it much harder for the fuel pump to smoothly deliver fuel at the specified pressure to the injector nozzles or carburetors. Ultimately, it could cause fuel pumps to fail through overheating or their own valve failure.
    • The structure of the fuel tank itself is only designed to withstand so much vacuum and, in a high vacuum situation, the fuel tank itself can be deformed by external atmospheric pressure pressing against too low an internal pressure.
    The problem with the EVAP on these bikes is that the check valve (or vacuum regulator) is a cheap device barely the size of a couple of large coins stacked together, and the charcoal canister is actually too small to operate very effectively as well. If you look at these systems on an automobile, for an engine barely twice the displacement of the V7 engine, the charcoal canister will be 4 to 8 times the volume and the vacuum regulator valve typically a similar amount larger as well. The problem is there aren't many good places to put such large components in the tight confines of a motorcycle's engine systems without them also being something of an eyesore. Combine this with the fact that the tiny amount of fuel carried by a motorcycle, and the relatively low percentage of motorcycles left sitting in the sun whilst parked (where static fuel evaporation would be at its worst), in the context of motor vehicles at large, means that the EVAP system on motorcycles at the present time doesn't contribute very much at all to the removal of fuel fumes from the atmosphere. It's hardly a big emissions problem at the present level of motorcycle population in urban areas, or the world at large.

    Meanwhile, the EVAP system, because of its underperforming specs and the fragility of the vacuum regulation device, can actually cause significant harm to the bikes' performance and running characteristics, and can cause costly damage to both fuel pump and tank. It definitely causes some issues with the ECU programming, which has to be tailored to the additional, variable draw of air/fume mixture into the intake plenum.

    I realized there was a problem the day I exited the freeway and came to a stop light at the end of the ramp: The engine first idled roughly and then stalled. Since I'd heard of the problem, I tested by opening the fuel tank cap, and was greeted by a "Pop!" as the slightly bowed fuel tank side panel returned to its proper shape as well as a big sigh as air rushed into the heavy vacuum inside the tank. I rode home and disabled the EVAP before I took the motorcycle out for the next ride. The problem has never reappeared, the bike does not put out any noticeable amount of gasoline fumes, etc etc. :D

    G
     
    Last edited: Jun 13, 2018
    Jonny G, aproud1, acidlaser and 5 others like this.
  12. Richard Ducati

    Richard Ducati Tuned and Synch'ed

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    Wow. Quite the explanation and understandably a major concern given the level of vacuum you were seeing in your tank. I'll follow your lead and just go to an open tank vent to avoid any possible issues.

    Best regards,

    --Rich
     
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  13. Richard Ducati

    Richard Ducati Tuned and Synch'ed

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    Done. Easy-peasy...clamped a vacuum cap on the intake manifold port and ran fresh tubing down from the tank vent. Removed everything in between. Glad to be free of that unnecessary system. Thanks for all the insight, Godfrey.

    Cheers,

    --Rich
     
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  14. Bruce Wharton

    Bruce Wharton Just got it firing!

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    Thanks for the great tutorial, Godfrey. I followed it and did the canister-ectomy today. And, as you might expect, two of the poor quality spring nut broke - one on the side cover and one on the starter cover. Can you point me toward a source for the "better quality" replacements you got? Are they M4? Thanks!
     
  15. Godfrey

    Godfrey High Miler GT Famiglia

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    You're welcome.

    The replacement clip nuts (yes, 4mm thread same as the originals) I bought from my dealer ... they are Ducati parts, I believe, PN 85040551A. However, I'm also sure you can find them on Ebay for less than the $2.12 apiece I paid (it was convenient because I was there...). Just search for "4mm clip nut" and you'll get a wide range of offerings.
     
  16. vagrant

    vagrant High Miler

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    Wouldn't doubt that Ace hardware has them.
     
  17. Bruce Wharton

    Bruce Wharton Just got it firing!

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    Yep, checked, but they only had M6 size.
     
  18. pmdmn

    pmdmn Just got it firing!

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    Bruce Wharton likes this.
  19. blakestree

    blakestree Just got it firing!

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    When faced with a swooshing tank, is it a good idea to open the cap to vent, periodically? Or, would that introduce too much moisture into the tank?
     
  20. Godfrey

    Godfrey High Miler GT Famiglia

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    Better a tiny bit of moisture than too much vacuum in the tank... !
     

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