Oil leak.

[audiomick]

I discovered the other day that the V11 Le Mans is dropping a bit of oil. Not much, about a 2" spot on the garage floor after about a week or 10 days.

 

My first thought was the sump gasket, but then I remembered that a very well informed person had predicted that the timing cover gasket and or the seal on the shaft to the alternator would start to leak sooner or later.

 

So I'm taking bets, what do the well informed and experienced people here reckon: is the sump gasket more likely, or the timing cover gasket and/or that seal?

 

I've got my bases covered, as I ordered gaskets for both and the seal today. I'd just like to know where to look first. The bi-annual roadworthiness inspection is due this month, so it would be good if I don't have to mess around too much to get the leak sorted.

[MartyNZ]

You might also consider the seal in the alternator spacer.

[audiomick]

Ok.

The seal I mentioned is #19 on this drawing

https://wendelmotorraeder.de/motorgehaeuse-v11-02-le-mansskura-ex-30_3006_300602_30060203_3006020330_300602033001.html

 

I wasn't aware of the one you are talking about. I wish I had been. It only costs about €1.60, but the postage is probably about €5,-.

Maybe I can get a suitable one from "my" mechanic. Or order some more stuff to make the postage worthwhile....

But before I order anything else, I need to have a closer look at where the oil is coming from. If that O-ring is the culprit, there must be oil coming out directly behind the alternator cover. If it is the seal, that would also be the case, I think. If it is the timing cover gasket, the leak must be further back, i.e. no oil traces from under the front cover.

 

While I'm at it, does one need a puller to get the alternator off? According to the PDF workshop book I have, it should just come off.

I have in mind the alternator on the V35 Imola. That is the "classic" Bosch alternator, and needs some persuasion to come off. Going by the drawing that Marty posted, the one in the V11 sits on a straight shaft and has a key to hold it in place. Should be easier to get off, I think, but am I right?

[docc]

A couple things first . . .

@audiomick, consider editing the signature in your profile to show the year of your LeMans. Certain changes through the range make the production year helpful. (I realize European model years" could vary from the rest of the world, but it's a start.)

Next, where does the leak appear relative to the front/rear, left/right of the motor? It is, for certain, motor oil? Does the motor, itself, show a wet area anywhere?

[audiomick]

32 minutes ago, docc said:

Next, where does the leak appear relative to the front/rear, left/right of the motor? It is, for certain, motor oil? Does the motor, itself, show a wet area anywhere?

The bike is a 2002 Le Mans, wrinkly paint on the motor, 15 M ECU, 43mm forks with rebound damping on both legs. I've added the date to my profile.

 

I haven't had a closer look at the leak yet. What I noticed was "very well oiled" on the right hand side of the sump. No oil above the sump spacer. I can't say how the left hand side looks.

The oil on the sump that I observed would be, perhaps, consistent with a leak low down on the right hand side of the timing cover, or perhaps towards the front out of the sump spacer gasket.

I'm not likely to get into the garage for the next couple of days. If I do, I'll have a closer look and report.

And yes, almost certainly motor oil. I know what gearbox oil smells like, and I didn't smell that.

[MartyNZ]

You should search this site for Valpolini. There's some useful comments about these hi zoot metal reinforced gaskets, especially in relation to the timing chest cover.

I asked Valpolini in Italy directly for some gaskets, but they declined to send to me. Luckily the NZ dealer could supply. You should have less trouble being nextdoor to them.

As for removing the alternator rotor, your biggest problem will be undoing the nut. Locking the crank using a big screwdriver in the bell housing porthole worked for me. Then a couple of pry bars can gently slide the rotor forward. 

Conventional wisdom says keep the rotor in the stator when off the motor to reduce loss of magnetism.

[docc]

The "wrinkly paint" 2002 V11 do seem over-represented in timing chest leaks.

+1 on @MartyNZ's advice . . .

Yet, also, consider cleaning all the surfaces and spraying a coat of "foot powder", take a ride and look for discoloration indicating the leak source.

 

 

[p6x]

15 hours ago, audiomick said:

is the sump gasket more likely, or the timing cover gasket

I had the same problem, last year, same question;

@docc suggested to use talcum powder to find out the origin of the leak. I posted pics in the thread somewhere. It works.

Replaced the timing cover gasket with the metal one; the one installed on my 2004 V11 Le Mans was stock, and paper. You could visually identify where the seal was broken.

 

[guzziart]

22 hours ago, MartyNZ said:

You might also consider the seal in the alternator spacer.

I goofed, didn't look at this illustrated parts breakdown for the alternator prior to pulling the front cover otherwise I would have definitely replaced the #9 oring.  I realized the oring was present when I was going back together and the oring offered a slight drag while sliding onto the shaft.  Anyway, if you're pulling the front cover, replace the oring imho.  Also, my spacer did not have a chamfer for an additional oring but a flange, the only way to remove the spacer is to remove the crank seal too or pull the cover. ... both after stator/rotor removal of course.

FWIW, I have about 200 miles on my Lemans since timing cover gasket replacement, went back with a "genuine" Guzzi metal/composite gasket and no leaks detected nor was gasket sealer used upon installation.  This gasket lined up perfect with bolt holes & bosses.  The same distortion/misaligned bolt holes I encountered with an aftermarket composite gasket I have also observed with a paper/fiber gasket from another dealer which leads me to think that whomever is making "knock off" gaskets used  a poor example for a template.

Art

[audiomick]

On 5/13/2023 at 2:15 AM, docc said:

... a coat of "foot powder"...

Yes, I'm aware of that trick. I'm not sure if we have talcum powder in the house, but I dare say I'll find something appropriate.

 

Thanks for the tips, everyone.