PRESSURE ADJUSTER

[Jose Paulo]

HI, IM FROM BRAZIL.I HAVE A V11 SPORT PURCHASE A FEW DAYS. THE TUBE FROM PRESSURE ADJUSTER IS DISASSEMLY. IS IT A ASSEMBLY ON THE LEFT THROTTLE BODY? THERE IS SOME PROBLEM STAY DISASSEMBLY?(NO CANISTER)

 

THANKS

[luhbo]

The pressure regulator is on the right side of the bike and not connected to the manifold. Connecting it to the right manifold will give you the one or other advantage concerning rideability, but most people don't think it's worth the effort.

 

Hubert

 

PS, one or two pics of what you are talking about might be helpful.

[raz]

It was recently discussed here: http://www.v11lemans.com/forums/index.php?...st&p=135971

 

I don't know of anyone with a V11 that has it connected. I intend to experiment with it later.

[luhbo]

It was recently discussed here: http://www.v11lemans.com/forums/index.php?...st&p=135971

 

I don't know of anyone with a V11 that has it connected. I intend to experiment with it later.

 

How many V11 owners and bikes do you know anyway <_>

 

But honestly, I've so far only read about it as well. Theory says it should be connected, those who have it so say it works better than without it.

 

 

Hubert

[raz]

How many V11 owners and bikes do you know anyway <_>

Well out of the 1,600 members on this forum you are the first to speak up, and still you don't have it connected yourself but have read about some people who has. Seems to me it's pretty rare! <_>

Anyway this is encouraging. It's such a cheap and easy fix. If it makes a noticable difference (to fuel consumption if nothing else) I'm puzzled why the word isn't spread. I will definitely get me a three way junction and connect both intakes. And report back here of course.

[luhbo]

... And report back here of course.

 

So will I On German forums you can read about that more often. Those people claim this mod would give a much better, softer transition, very useful in slow curves or in rain f.i.

 

Hubert

 

But what with Paolo? Hey, are you still out there? It's your thread ...

[dlaing]

HI, IM FROM BRAZIL.I HAVE A V11 SPORT PURCHASE A FEW DAYS. THE TUBE FROM PRESSURE ADJUSTER IS DISASSEMLY. IS IT A ASSEMBLY ON THE LEFT THROTTLE BODY? THERE IS SOME PROBLEM STAY DISASSEMBLY?(NO CANISTER)

 

THANKS

Welcome to the forum!

Good to see there is at least one V11 in Brazil.

Did you buy it in Montevideo, Uruguay?

I don't know how good your access to parts is in Brasil, but you may discover the internet is a great way to order parts. Especially from v11lemans.com forum sponsors!!!

 

 

Looking at the image Luhbo posted, you will see a grey hose. Normally that hose is not there. If it is not there, do not worry.

But there is also a fitting at each throttle body that should be capped off.

The other posters are discussing the theory that the hose should go from the pressure regulator, form a "T" and branch off to the two throttle bodies.

But it is only a theory, that some believe will improve the bike.

Your bike should have been built with no hose there.

 

 

 

You may be looking at a fuel pressure relief hose coming off of the fuel tank???

That hose merely needs to vent or breathe.

[Ryland3210]

Welcome to the forum!

Good to see there is at least one V11 in Brazil.

Did you buy it in Montevideo, Uruguay?

I don't know how good your access to parts is in Brasil, but you may discover the internet is a great way to order parts. Especially from v11lemans.com forum sponsors!!!

 

 

Looking at the image Luhbo posted, you will see a grey hose. Normally that hose is not there. If it is not there, do not worry.

But there is also a fitting at each throttle body that should be capped off.

The other posters are discussing the theory that the hose should go from the pressure regulator, form a "T" and branch off to the two throttle bodies.

But it is only a theory, that some believe will improve the bike.

Your bike should have been built with no hose there.

 

 

 

You may be looking at a fuel pressure relief hose coming off of the fuel tank???

That hose merely needs to vent or breathe.

 

It turns out it is more than a theory, Dave. It is described in the Service Manual and illustrated as connecting to both intake manifold ports via a T. The manual stresses the importance of having the pressure regulator referenced from the intake manifold pressure.

 

My '04 Cafe Sport has the internal fuel pump/regulator/filter assembly within the tank. If I ever get the thing apart, I plan on seeing if I can't create a port.

[Dan M]

It turns out it is more than a theory, Dave. It is described in the Service Manual and illustrated as connecting to both intake manifold ports via a T. The manual stresses the importance of having the pressure regulator referenced from the intake manifold pressure.

 

My '04 Cafe Sport has the internal fuel pump/regulator/filter assembly within the tank. If I ever get the thing apart, I plan on seeing if I can't create a port.

 

As discussed at some length in earlier threads, vacuum operated pressure regulators are nearly always hooked to manifold vacuum. The idea is to bump pressure when the throttle is opened. The bump in pressure along with the increase in pulse-width by the injector driver gives an accelerator pump effect as the throttle is opened. I have not checked the pressure difference on the V11 with or without vacuum but a typical regulator reduces pressure by 5 - 10 psi when vacuum is applied. What I do know is I tested CO output with and without vacuum and got a significant reduction in CO at idle with vacuum applied. I did this last summer and don't recall the actual before / after readings but I'm thinking CO at idle without vacuum was about 3.5% or so and down around 2% with vacuum. The only down side I can see of having it connected is they fail with some regularity on cars and when they do, fuel under pressure is forced into the manifolds through those vacuum hoses flooding the engine. I don't know why most of our bikes come with it open to atmosphere but figured MG did it for a reason.

[dlaing]

It turns out it is more than a theory, Dave. It is described in the Service Manual and illustrated as connecting to both intake manifold ports via a T. The manual stresses the importance of having the pressure regulator referenced from the intake manifold pressure.

 

My '04 Cafe Sport has the internal fuel pump/regulator/filter assembly within the tank. If I ever get the thing apart, I plan on seeing if I can't create a port.

It is still only a theory that it makes the bike run better.

To prove otherwise you would need a multigas dyno analysis across the entire map, both hooked and unhooked.

The greatest vacuum and potential leanness occurs during high RPM deceleration. This would most likely cause increased popping during deceleration. It is common with a PCIII to increase richness at closed throttle to make it run better.

The least vacuum occurs during WOT at low rpms. This would likely increase richness and probably cause it to fail emission testing. EDIT it will only make it relatively richer to other places on the map, not relative to the disconnected state. Thanks Raz!

Did Guzzi change their mind?

Did disconnecting it help them pass emission testing?

Why didn't they just change the map in the ECU?

Maybe they changed the map after they changed their mind?

We don't know the answers. Until proven otherwise, it is simply all theory that the bike is designed to run better with it hooked to manifold.

[raz]

I agree it's not proven but the few reports I've heard are positive. Also, some FWIW facts:

• The WHB (both yours and mine) says it should be connected. It's never pictured and it's not in the parts manual but still, it is clearly in the text (using the word 'must'). In the generation before mine, it was pictured too, routed to both manifolds.
  
• Connecting it will not result in richer mixture at any time, just leaner at low load.
  
• The specs for the injector says it will atomise the fuel forming a cone of 30° at a fuel pressure of 3±0.2 bar (44±3 psi). This must be referenced to where it injects to, not free air. Without connecting this hose we will get well out of this range at certain conditions and the way I read it, this may result in bad atomising at low load or decel. Edit: The striked-out sentence is probably wrong, as discussed below.
  

Anyway I have ordered what I need to do this mod. and I will report back.

[Skeeve]

Anyway I have ordered what I need to do this mod. and I will report back.

 

Please do! I'm very interested in what would be required to connect the vacuum taps to the fuel pump [located inside the tank!] safely. Really not interested in fuel leaks of any type, esp. pressurized! I imagine that this additional complexity might have been what led Guzzi to just delete the connection when they submerged the fuel pump to resolve the vapor-lock issue...

 

I'll await your report!

[raz]

Please do! I'm very interested in what would be required to connect the vacuum taps to the fuel pump [located inside the tank!] safely. Really not interested in fuel leaks of any type, esp. pressurized! I imagine that this additional complexity might have been what led Guzzi to just delete the connection when they submerged the fuel pump to resolve the vapor-lock issue...

 

I'll await your report!

Your fuel pump is inside the tank, but is the pressure regulator too? Mine is not, it's on the right side of the tank. The V11's I know of look like mine in that aspect.

[dlaing]

[*]The specs for the injector says it will atomise the fuel forming a cone of 30° at a fuel pressure of 3±0.2 bar (44±3 psi). This must be referenced to where it injects to, not free air. Without connecting this hose we will get well out of this range at certain conditions and the way I read it, this may result in bad atomising at low load or decel.

Anyway I have ordered what I need to do this mod. and I will report back.

Interesting point!

Looking forward to the results.

[Guest ratchethack]

Wasn't this just covered in another thread??

 

I tried connecting the fuel regulator pressure reference to the intake "recovery canister/balance" barbs many years back. There was ZERO noticeable difference after a few days. No, I didn't do an exhaust gas analysis or dyno before and after. Instead, I simply re-plugged the barbs. It occurs to me that the .030" bore of the intake barbs is inadequate to handle throttle transitions.