Oil leak

[richard100t]

I have an oil leak coming from the front of my engine near the timing chain cover. There is also a sensor near the cover on the clutch/shifter side. Its kind of hard to tell where the leak is coming from at this point. I remember some members telling about changing either a gasket or a seal behind the timing cover. Can that sensor near the cover weep oil? I'm not even sure what its for yet My bike has about 18k miles on it now, does anyone have a guess about the leak?

[callison]

I'd check the crankcase to spine breather hose first. They rot, then they leak. Since it's up underneath the tank it's easy to overlook. You may have to pull the tank to check it. Somewhere here, there is a thread (or two) on aftermarket replacement parts that can be made to fit rather than relying upon MGNA to actually have something in stock for an outrageous price.

[richard100t]

I'd check the crankcase to spine breather hose first. They rot, then they leak. Since it's up underneath the tank it's easy to overlook. You may have to pull the tank to check it. Somewhere here, there is a thread (or two) on aftermarket replacement parts that can be made to fit rather than relying upon MGNA to actually have something in stock for an outrageous price.

Thanks a lot Carl, I appreciate the advice. I hope you're right as that would indeed be a very fast, cheap and easy thing to fix.

[richard100t]

Upon further inspection now that the bike has cooled down, I tried that sensor thats behind the shifter side header as it comes right out of the head. What is this for? Anyway it had the most caked on oil & gunk so I decided to have it out & take a look at it. I put the allen head socket in the bolts & guess what? They were barely more than finger tight. Whats more, Guzzi uses a steel gasket between the sensor & the block. I put it back in & snugged up the bolts firmly, but not overtight. Hopefully this is where the leak is from. I would recommend for anyone to check these bolts as like I said mine felt like they would have been on the highway in a few thousand more miles if I hadnt noticed it.

Btw I cleaned the sensor & the bolts up & I'll ride it later when it stops raining to post an update.

[Guest ratchethack]

Upon further inspection now that the bike has cooled down, I tried that sensor thats behind the shifter side header as it comes right out of the head. What is this for? Anyway it had the most caked on oil & gunk so I decided to have it out & take a look at it. I put the allen head socket in the bolts & guess what? They were barely more than finger tight. Whats more, Guzzi uses a steel gasket between the sensor & the block. I put it back in & snugged up the bolts firmly, but not overtight. Hopefully this is where the leak is from. I would recommend for anyone to check these bolts as like I said mine felt like they would have been on the highway in a few thousand more miles if I hadnt noticed it.

Btw I cleaned the sensor & the bolts up & I'll ride it later when it stops raining to post an update.

Richard, you're describing the timing sensor. It's notorious for seeping a little oil from the timing case. The "gasket" you're referring to is actually a very soft aluminum shim, which is very easily bent. It's critical not to damage this and get it back in place so as to maintain the correct clearance between the sensor and the timing pickup on the cam sprocket. The sensor should be kept clean to ensure a good signal, so it's good to remove any buildup on it, but I've never actually heard of a sensor problem due to this. I'd be very careful NOT to overtighten the socket-head screws, and would suggest mild threadlocker like Loctite Blue. You don't want to distort the shim. I've tried several kinds of sealant (GE Silicone Seal, Hylomar, Yamabond, etc.) very thinly applied on both sides of the shim with marginal results. Let us know if you've found the magic goop -- in my experience, just when you think you've got it knocked, it shows up again.

[richard100t]

Richard, you're describing the timing sensor. It's notorious for seeping a little oil from the timing case. The "gasket" you're referring to is actually a very soft aluminum shim, which is very easily bent. It's critical not to damage this and get it back in place so as to maintain the correct clearance between the sensor and the timing pickup on the cam sprocket. The sensor should be kept clean to ensure a good signal, so it's good to remove any buildup on it, but I've never actually heard of a sensor problem due to this. I'd be very careful NOT to overtighten the socket-head screws, and would suggest mild threadlocker like Loctite Blue. You don't want to distort the shim. I've tried several kinds of sealant (GE Silicone Seal, Hylomar, Yamabond, etc.) very thinly applied on both sides of the shim with marginal results. Let us know if you've found the magic goop -- in my experience, just when you think you've got it knocked, it shows up again. <_>

So you have actually had this sensor out several times & used a different sealant each time? On top of that have you personally used the Loctite Blue? What was the reason that you kept trying different sealants? Did the sensor keep getting loose or did it just keep weeping oil that made you switch products? I've been looking for a good excuse to get a bottle of Loctite anyway. Would too much sealant actually affect the correct clearance between the sensor & the timing pickup? Enquiring minds wanna know :!:

Btw Ratchet...how many times have you stripped your bike down & put it back together lol? It seems you're familiar with every little washer & nut.

[Guest ratchethack]

So you have actually had this sensor out several times & used a different sealant each time?

Richard, I think I've had it out 4 or 5 times. I tried GE Silicone Seal several times and wasn't pleased with the remaining seep after a few thou miles. Ditto other stuff, still seeps. To my way of thinking, it shouldn't seep AT ALL!

On top of that have you personally used the Loctite Blue?

But of course! I use it wherever any steel fastener goes into aluminum, and for just about every other steel/steel threaded fastener on the bike. Decades of use on dozens of engines, bikes, cars, etc.... Doesn't everyone?

What was the reason that you kept trying different sealants?

I can't recall such a simple-looking thing being so stubborn to seal! It's not like the thing has any appreciable pressure behind it??!!

Did the sensor keep getting loose or did it just keep weeping oil that made you switch products?

It never was loose. I was just chasing the seep.

I've been looking for a good excuse to get a bottle of Loctite anyway.

Don't take this the wrong way, Richard -- but I can't conceive of owning a motorcycle without Loctite Blue (or equivalent) close at hand at all times, and a tube of Loctite Red in the drawer with the rest o' the various sealants!!!

Would too much sealant actually affect the correct clearance between the sensor & the timing pickup? Enquiring minds wanna know :!:

In my opinion, this is one of those applications where the critical clearance determined by the shim might be thrown off by too much sealant. I've used it very sparingly here. It occurs to me that the soft aluminum isn't the best surface to get sealant to adhere to between the flange on the sensor and the case. After careful scrub-down of everything with lacquer thinner and "surgical" cleanliness, I've tried a little "fillet" of sealant around the cylindrical part that goes in the case, and another little "fillet" around the flange.

Btw Ratchet...how many times have you stripped your bike down & put it back together lol? It seems you're familiar with every little washer & nut.

Richard, when I get a new bike, I make it a practice to go thru it from stem to stern fairly rigorously to familiarize myself with the components, adjustments, and overall status of things. Nearly everything accessible gets threadlocked and where appropriate, torqued. In the case of the Guzzi, I was "blessed" with the opportunity to have the trans out for the infamous trans recall on my series of bikes. I chose to have the trans out and back in myself rather than have the dealer do it. They couldn't have been happier with this arrangement, whereby they did the "inside the box" work and got paid for the whole job by Guzzi, and I learned a lot very quickly. The only remaining "unmolested" parts last touched by Mandello are the crank, cam and followers, rings, and inside the heads. Heads are next on the agenda.

 

FWIW: I just looked up the timing sensor in the Service Manual. Guzzi offers different shims. They're spec'd out by 0,1 mm thicknesses and the air gap spec between sensor and pickup on the cam wheel is 0,7 - 0,9 mm. It must be a Hall Effect sensor, but this would be strictly speculation on the part of a Perpetual Journeyman Shade-tree mechanic.

[richard100t]

Well now I have ridden the bike a good 50 miles since I cleaned up the sensor & wiped the area clean. So far I havent been able to find any other source of leakage. Assuming it was the sensor weeping oil, I can live with that amount of leak. I'm not going to put any sealant on the aluminum gasket but I will eventually get some loctite & treat the bolts.

[kevdog3019]

I thought that was the RPM sensor. Is that synonymous with timing sensor? I've done both Breva 750's with silicon and they seem to be pretty good now. The wife's was blowing oil out when we caught it. She said "look at my Stitch...it's caked with oil." Left head had oil all over it and running down left side of bike. Found the culprit and got to mine before it gave me fits.

[Guest ratchethack]

I thought that was the RPM sensor. Is that synonymous with timing sensor?

Yep, it's wot drives the EFI and tach. Also known as T.D.C. sensor in the Guzzi manual.

 

The last sealant I tried was hylomar. Same thing happened with GE silicone seal and Yamabond: 50 miles -- no seep. You think you've nailed it. A few hundred miles yesterday, and it's seeping again.

 

Time f'er more serious measures: Indian Head Gasket Shellac.

 

Will advise.

[docc]

Having discovered the whole left side of the engine oily and dirty, I've been chasing a leak which has led me to the phase/revolution sensor. After a new O-ring and such, it looks like the oil is coming through the sensor. Could it be so? Can this be sealed?

[luhbo]

I'm not sure whether you really want to. If the part fails you'll push your bike.

 

Hubert

[docc]

I'm not sure whether you really want to. If the part fails you'll push your bike.

 

Hubert

 

Good point as usual, Hubert!

 

I'll get a call in to my World Famous Parts Man.

[richard100t]

I tried using gasket sealer on mine and I think it just made it worse. It seems that it was designed to fit in there with no sealant so I finally cleaned all the sealer off, made sure it was spotless and carefully bolted it back on. What I mean is I tried to bolt it back on the way you bolt a wheel on a car. I never replaced the gasket and it still hasnt leaked in these last few years. Its probably just that the gasket has to seat in there perfectly or it will drip a little.

[docc]

The seal doesn't appear to be leaking on this one. The oil looks to be pushing through the sensor itself. A new one is 167USD, or a couple hundred bucks / a-buck-euro-fifty. Too many lire to count. Crazy.

 

I'll have to try and have my way with it using my arsenal of sealants and adhesives.

 

150 Euro . . . I just can't.

 

Please say a little prayer for my RTV silicone.