Bell Housing Leak

[docc]

One of the great past-times at motorcycle events is to gather about the bikes of an evening and chat it all up over a pint. Little goes unnoticed by the enthusiasts and at Barber Vintage Festival some keen lad noticed a wee drip on the ground under the left rear corner of my sump. Engine oil.

 

Groan . . . wet alright, the entire back corner. Arriving home I found this:

 

But felt a glimmer of hope finding the dip stick O-ring all flattened out:

 

Cleaned it all up and applied gstallons' tried and true spray foot powder to see this at the weep hole of the bell housing between the engine and gearbox below the clutch:

 

First thought, of course: Bugger! A rear main seal .

 

Thank goodness for this forum. A little search time brought up this post by The Lovable and Cuddly Pete Roper:

 

"1.) Almost always leaks from the bell housing can be traced back to the breather hose that comes off the pipe from the top of the bell housing. Guzzi, for expediency clamp this with a shitty clamp like the sort of thing that they use for ringing birds! they also use really crap hose that tends to perish quickly and crack. When the clamp loosens or the hose cracks or collapses the hose leaks, it then runs down through the hole the pipe pokes through, through the bell housing and dribbles out of the drain slot and people who should know better say, "Uh! You've got a blown rear mainseal mate! That'll cost you a zillion dollars to fix!". If you're lucky while they are pulling the old tart apart they'll notice the pipe is a bit ordianary and replace it and then the leak will be fixed. If not then the leak will recurr within a few days, you'll get the sh!ts, the dealer will get the sh!ts with you, you'll sell the bike and then spend the rest of your life saying Guzzis are awful sh!theaps. Simply replace the hose first, make sure the ball valve is there and not gummed up and use decent clamps to secure it."

 

A quick look, and the top of the engine and gearbox junction are all nasty and wet. The clamp on the oil hose tightened about a turn and a half or more. Cleaned it all up and had a ride. Dry on top. I'll expect a little residual from the weep hole for a time, but it certainly not the Exxon Valdez which gives some hope!

 

Thanks very much to Pete Roper for all his contributions. How much I appreciate having this forum to turn to!

 

Wish me luck then! Sometimes you can keep searching the internet til you get the answer you want whether it is right or not!

 

 

 

 

[docc]

I got looking for the "check valve" in the crankcase breather. I can't find it in the Workshop Manual or the Parts Listings.

 

Where is it, actually?

[Baldini]

Hi Docc,

 

On Tontis, there is a check valve (as shown in your link). It sits in the mouth of metal pipe that exits centre top of bellhousing. This pipe is the main crankcase breather & connects via a hose to a breather box that sits above it. V11s vent pipe connects to a longer hose that vents to frame near headstock. I remember I replaced that hose but I can't recall if there was a valve in there. As you say the parts list does not show one. Sorry I can't be definitive, someone will be along soon, no doubt.

 

Cheers,

 

KB

[gstallons]

It sits in the vent pipe that protrudes out of the engine case . It may "stick" in the vent hose or it may remain in the vent pipe . It performs a similar function as a PCV valve in automobiles .

[docc]

We are to presume it is considered part of the vent pipe for parts and assembly purposes?

 

I'm afraid to go looking for mine since I think the hose would be destroyed.

[gstallons]

Don't worry..................it will crumble !

[GuzziMoto]

The V11 uses a crank case vent up to the frame behind the steering head. From there the oil separates out and drains back down into the bottom of the crank cases. The air vents out the top of the frame and runs to the airbox as I recall.

If you put a one way valve on the crank case breather with that set up it would prevent air from being sucked in to the crank cases through the breather when the pistons rise. This could/would suck air through the vent at the bottom of the cases where the excess oil drains back to the cases from the frame. While I don't think that would be a really bad thing, it would prevent a one way valve at the crank case vent from really working as it should. It might also cause some foaming of the oil when said air bubbles up. But probably not enough to matter. But unless you had a one way valve in each of the two lines you could not generate real negative pressure in the crank cases (which is the purpose of the PCV valve) and if you did oil would not be able to drain back in.

I have played with one way valves on my Daytona, which has a similar set up to the V11. I have not yet found the method I like best.

But I think the older Guzzi's that have the one way valve don't share the return line where the oil that separates out from the breather drains back below the oil line in the cases.

I am pretty sure that the V11 does not have a one way valve in its breather and positive my Daytona does not. I think that valve is for the older and touring style Guzzi's. I believe the Cali's of the same vintage as the V11 may have had the valve. But that last part is a guess.

[docc]

Has anyone ever actually seen this check valve in the breather tube of a V11?

 

Otherwise, it will be one less thing to worry about and I can remove the reference from the "Tank Off Maintenance Checklist" in FAQ . . .

[moto fugazzi]

I didn't have a check valve in my 2001 V11S, but I'm not the original owner. I don't think the PO had the breather hose off at any time.

Ken

[docc]

I am beginning to think the check valve was used when the vent went to a canister and before the system was closed with a vacuum applied from the airbox connection . . .

[czakky]

My Lemans didnt have a check valve in the tube. Guess I assumed it was in the crankcase. My tube looked original but who knows?? I'm the third owner.

[docc]

No valves and counting . . .

[GuzziMoto]

The V11 uses a crank case vent up to the frame behind the steering head. From there the oil separates out and drains back down into the bottom of the crank cases. The air vents out the top of the frame and runs to the airbox as I recall.

If you put a one way valve on the crank case breather with that set up it would prevent air from being sucked in to the crank cases through the breather when the pistons rise. This could/would suck air through the vent at the bottom of the cases where the excess oil drains back to the cases from the frame. While I don't think that would be a really bad thing, it would prevent a one way valve at the crank case vent from really working as it should. It might also cause some foaming of the oil when said air bubbles up. But probably not enough to matter. But unless you had a one way valve in each of the two lines you could not generate real negative pressure in the crank cases (which is the purpose of the PCV valve) and if you did oil would not be able to drain back in.

I have played with one way valves on my Daytona, which has a similar set up to the V11. I have not yet found the method I like best.

But I think the older Guzzi's that have the one way valve don't share the return line where the oil that separates out from the breather drains back below the oil line in the cases.

I am pretty sure that the V11 does not have a one way valve in its breather and positive my Daytona does not. I think that valve is for the older and touring style Guzzi's. I believe the Cali's of the same vintage as the V11 may have had the valve. But that last part is a guess.

I thought I explained it here. I guess I was not adamant enough.

Some Guzzi's had a check valve. The nature of a V11 breather system precludes it. Cali's and earlier Guzzi's are where you would be likely to find the check valve.

[docc]

Understood. I counted your post among the opinions that there is no check valve in the V11. 

 

If there is a valve, it would be exactly as gstallons noted: like a PCV valve on a passenger vehicle. These are simple ball valves that are "pulled" open by intake vacuum. As noted, the upper (spine) frame member receives the crankcase vent hose and the oil fraction settles in the frame returning to the crankcase through the return line on the lower left side of the frame. Intake vacuum is applied from the airbox by a hose that connects the forward left side of the airbox to the banjo fitting visible at the top of the frame just behind the headstock pulling the oily vapor portion from the crankcase back into the aibox. If there were a check valve, it would be "opened" by this vacuum.

 

So far, I'm with GuzziMoto and moto fugazzi, also baldini and czakky :    "No PCV check valve on the V11."

 

I've amended the "Tank Off Maintenance Checklist" in FAQ.

 

Anyone finding a check valve in their vent pipe under the crankcase vent hose needs to "pipe" up!

[moto fugazzi]

I have some leaking at my bell housing as well, and it doesn't smell like gear oil. The breather hose was replaced this year, and there's no leaks from there. The leak is getting gradually worse, but isn't bad yet. I wonder if I can remove the starter and take a look inside with a mirror and flashlight to find the leak?

FWIW, I'm told the PO had the rear main seal replaced under warranty at under 1K miles.

Ken