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Alex, “oil leaks for $200”

FedeleMotoGuzzi

FedeleMotoGuzzi

Tuned and Synch'ed
GT di Razza Pura
Joined
Dec 22, 2021
Messages
87
Location
Southeast Texas
We all like to play the “what’s leaking oil” guessing game.

In previous posts, I cleaned up my new to me 2003 EV by changing all fuel lines, fuel filter, EVAP delete, changed all oils, new tires blahX3.

Last week I rode about 3 miles to check out the steering before raising forks ~1/2”. Today I rode for just less than an hour on the highway. First half steady 3500 RPMs to get a feel for bike and check out the side to side fork wobble without fork snubber installed. Coming back, I ran up and down the RPM range and noticed the clutch slipping in 5th when I cranked on the throttle. Stopped and check the free play and it was good. Did not “notice” any oil on the outside of engine at this time (wasn’t looking either) nor did I smell any. When I pulled into the driveway, there was plenty of oil on the engine. There is oil as far forward as the coils.

Engine is too hot to remove the tank, but I’m wondering if the large frame vent line came off.

Anyone want to play the guessing game?

I’ll remove the tank tomorrow and see what I can find. Will post the results tomorrow or Monday.

IMG_9050.png IMG_9051.png IMG_9052.png IMG_9053.png IMG_9054.png IMG_9055.png IMG_9049.jpeg
 
kenrover said:
I'm not certain from the pics, but my guess is rear main oil seal.
Click to expand...
Not rear main. The oil won't go up. Likely a vent line. As for clutch slip, only oil from the gearbox can get to the clutch plates. Flywheel prevents engine oil from getting to the clutch plates.
 
Last night I dreamt that I over serviced the recent oil during oil change. How's that for having the issue on my mind? Will take tank off this evening. I am prepped for the worse case scenario! :)
 
The rear main seal relies on being periodically heated and bathed in engine oil to maintain its flexibility.

When a motorcycle sits for years, the seal dries and becomes brittle.

Then, when putting the motorcycle back into service, the heating and cooling actually cause the seal to crack and weep and this oil drips down right onto the clutch pack.

You notice the effects (slippage) when running hard in high gear or climbing steep grades.

If you look under the bottom rear of the clutch bell housing with a mirror, there is a weep hole at the bottom and oil coming out of this hole, is a dead giveaway of the damaged rear mainseal condition.

This is a Quota, but you get the idea and can see the oil running downwards from the leaking rear mainseal.

 
MotoGuzziFan said:
The rear main seal relies on being periodically heated and bathed in engine oil to maintain its flexibility.

When a motorcycle sits for years, the seal dries and becomes brittle.

Then, when putting the motorcycle back into service, the heating and cooling actually cause the seal to crack and weep and this oil drips down right onto the clutch pack.

You notice the effects (slippage) when running hard in high gear or climbing steep grades.

If you look under the bottom rear of the clutch bell housing with a mirror, there is a weep hole at the bottom and oil coming out of this hole, is a dead giveaway of the damaged rear mainseal condition.

This is a Quota, but you get the idea and can see the oil running downwards from the leaking rear mainseal.

Click to expand...
More likely gearbox input seal, or the sealing rubbers on the clutch push rod leaking causing the clutch to slip. Engine oil can't get to the clutch. It is enclosed in the flywheel and the flywheel will deflect any engine oil from getting to the clutch plates. As I said earlier, oil on the engine is from a vent line. He may have excess crankcase pressures causing the vent line issue.
 
If you smell oil that's coming out of weep hole on bottom of bell housing you'll know if engine or trans.
The big 'S' shaped hose that blows up into frame are known to crack & leak, bad Italian rubber.
My Cal2 has had rear main leak for over 25yrs, clutch has 100K mi on it & doesn't slip even pulling a sidecar at 100mph in 5th.

I wonder if it is a Hydro w/single plate clutch, I think they had those then like the V11 Sport model. Can't remember for sure.
 
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V700Steve said:
If you smell oil that's coming out of weep hole on bottom of bell housing you'll know if engine or trans.
The big 'S' shaped hose that blows up into frame are known to crack & leak, bad Italian rubber.
My Cal2 has had rear main leak for over 25yrs, clutch has 100K mi on it & doesn't slip even pulling a sidecar at 100mph in 5th.
Click to expand...
And that big vent hose is part number 00823956080
 
In any event, whenever I have to separate a gearbox from an engine, I go ahead and update everything I can. For a 2003EV, that would be rear main, gearbox seals, and o-rings, and the 3205 input and output bearings get replaced with steel cage bearings. I've seen too many of the plastic cage ones fail. If there are enough miles, the clutch plates and hub gear. Since yours is slipping, then do the clutch plates. If a single plate, convert to dual plate clutch. The single plate units were an experiment that failed. I've converted a couple that had single plate clutches, but they were spine frame bikes.
 
john zibell said:
In any event, whenever I have to separate a gearbox from an engine, I go ahead and update everything I can. For a 2003EV, that would be rear main, gearbox seals, and o-rings, and the 3205 input and output bearings get replaced with steel cage bearings. I've seen too many of the plastic cage ones fail. If there are enough miles, the clutch plates and hub gear. Since yours is slipping, then do the clutch plates. If a single plate, convert to dual plate clutch. The single plate units were an experiment that failed. I've converted a couple that had single plate clutches, but they were spine frame bikes.
Click to expand...
If it leads me to splitting the thing, then I will follow your wise recommendations. Thanks for the suggestions.
 
Took the tank off and here is what I found. I had left the frame upper forward vent line disconnected. Obviously, it’s at the highest point and wouldn’t be leaking right this second nor probably even when it is idling. But more than likely was source of the oil cover wiring immediately below/above it around the frame during higher reving.

Looks like there might be an inspection port on the right side of the bell housing. Tomorrow, I’ll bring home a boroscope and look around in there to see what I can see. A single thing that is bothering me regarding the clutch slipping symptoms, was that in fifth gear at 50-55 mph when I cranked on the throttle, it almost felt like the rear tire spun on the pavement and the bike slightly fishtailed. The first time I pawned this off as engine torque pushing the bike sideways, I did it a second time to verify. Repeated the same rpm rise and fishtail feeling. Could not conclude and didn’t want to do it again. Part of me is hoping that there was oil on the rear tire and the tire broke loose from the pavement versus the clutch slipping. I guess we’ll know tomorrow when I take a peek inside the bell housing.

Also, not seeing any oil dripping out of the bottom of bell housing (from inside).

One more also, I checked the oil level and it was JUST on top of the top line.

IMG_9072.jpeg IMG_9073.jpeg
 
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You won't see much when you remove that rubber plug on the side. On older bikes it is removed to see the timing marks on the flywheel. Take a picture of what is behind the rubber plug. We can tell if it is the wide flywheel (two plate clutch) or narrow for the single plate. I think you have found your problem from that vent hose. At least now the components up top won't rust with a good coating of oil :giggle:Possible you have oil on the tire, clean it off well,
 
FedeleMotoGuzzi said:
Took the tank off and here is what I found. I had left the frame upper forward vent line disconnected. Obviously, it’s at the highest point and wouldn’t be leaking right this second nor probably even when it is idling. But more than likely was source of the oil cover wiring immediately below/above it around the frame during higher reving.
Click to expand...
That frame fitting is really too large for the hose that's supposed to go onto it. The fitting is ~ 10 mm/3/8" and the hose from the airbox is 8mm/5/16". I buy a 5/16" to 3/8" plastic adapter at the hardware store, use a short length of 3/8" hose on that frame fitting to the adapter and 5/16" the rest of the way. Clamps on every connection point.
 
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