V7 III Evap/Tip removal

[JACoH]

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.

 

[GuzziTex]

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.

Thanks!

 

[Mayakovski]

• If you remove the evap can and care about the smell, I am working on making a nice small inline filter that will help with fumes. I will put it online when I have it well tested.

Any update on this filter?

 

[BearV7]

Any update on this filter?

Also interested in this...

 

[BearV7]

• If you plan on leaving the evap can in place... Instead of cutting the (tank breather) tip over valve line and removing it, I highly recommend gutting the valve by popping it apart, or installing a fitting that allows the vapors to flow into the canister if you don't want any fuel smells in your garage. If you leave vented to open air, be aware that fuel will flow from this line while the tank is topped off at any sudden stop or side-standing of the bike.

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

 

[Godfrey]

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.

 

[Richard Ducati]

I disabled the EVAP system first to prevent it oil canning the fuel tank, since I noticed vacuum building up in the fuel tank and odd running behavior within only a couple of hundred miles from new.

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

 

[Mayakovski]

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

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

 

[Godfrey]

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.

 

[Richard Ducati]

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....

 

[Godfrey]

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.

G

 

[Richard Ducati]

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

 

[Richard Ducati]

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

 

[Bruce Wharton]

Todd's been stressing I should can the evap system and its 'vacuum leak' since I started talking to him about the ECU reflash for Racer. Well, this morning, my second test of the ECU map with a stone-cold start on a chilly morning proved conclusively that Todd's work on that is absolutely spot on: Start, fifteen seconds to get a little heat into the cylinders, ride away ... no stumbles, no lean spot, nada. Just perfect. Thanks Todd!

But, as I returned home a couple of hours later, I noticed that the idle revs were acting a little "funny" and that the throttle seemed a hair "sticky." No idea why, but killing the motor and restarting cured both symptoms. Two miles later as I pulled into my driveway, the sticky throttle sensation was back again.

On a hunch, I opened the tank and heard a gasp of air, there was a vacuum building up in the tank. Ah hah! the evap can and it's valve were screwing up as I was told.

I spent a bit of time with the V7III ABS Service Station Manual PDF and finally found the evap system on page 234-237 as "Sistema evaporativo canister". Now I could see where they were located approximately and understand the operation completely. Vacuum line connects to the evap can to draw fumes through the tank breather after passing them through the charcoal. The valve is supposed to limit how much vacuum is applied and vent when it's too much. Obviously, it wasn't working right. A cheap and crappy valve, essentially, is the cause of the problem. But the system is ugly anyway and almost totally unnecessary for the evaporative emissions of a motorcycle.

Not having much time, I pulled the seat, side cover, and starter cover. Yup, there are the lines from the intake manifold to the canister under the gearbox, there's the tank line with the valve in it. Looking at the flow from manifold to canister, it was obvious how to do the quick'n'dirty: I cut the line going to the manifold and stuffed a blanking plug into it to stop the vacuum leak. I then cut the line coming from the tank vent and going into the canister just above the valve gizmo, and cut the bottom line and the valve off the canister. No more vacuum leak, and the tank now vents to atmosphere exactly the same way my LeMan V tank did ... just a small line leading from the top of the tank down behind the starter.

Procedure:

- remove seat
- remove left side panel (three bolts)
- remove starter cover (two bolts)
- locate vacuum tap line from manifold to canister under the gearbox
- locate breather line with valve connected to canister
- cut vacuum line and block it (I glued an aluminum slug in place)
- cut breather line above the valve and below at the canister inlet
- leave the breather line open ended behind the started ... put a filter on it if you worry about environmental dust getting into the tank
- replace starter cover
- replace side cover
- replace seat​

You're done.

note: Another one of those cheap clip nuts broke when I removed the side cover. Glad I got six better quality spares! That's three now... I'm going to pick up another dozen because I see them all over the place on this bike.

I'll clean up my work next time I get a chance by removing the vacuum line and canister completely and using a good vacuum tap plug, maybe extend the breather line down an inch or two and put a little filter trap on it. But this will suffice for the present.

I'll see what its behavior is on my run out for dinner tonight.

BTW: Is this little valve on the breather line what's referred to as the "tip valve"? Or is that something else still? ... Thanks!

G

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!

 

[Godfrey]

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!

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.

 

[Vagrant]

Wouldn't doubt that Ace hardware has them.

 

[Bruce Wharton]

Wouldn't doubt that Ace hardware has them.

Yep, checked, but they only had M6 size.

 

[pmdmn]

I have V7 III Stone and the side panel screws are M5x9. I purchased these M5 clips and they work fine: ebay.com/itm/10x-Fairing-5mm-Bolt-Kit-Screw-Speed-Spire-Fastener-Clips-Nuts-Universal-Scooter/273199362876
Auto parts stores typically won't have anything smaller than M6 and I couldn't find anything smaller than M6 on Amazon.

 

[blakestree]

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?

 

[Godfrey]

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?

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