It would seem I have a right hand rocker cover gasket failure, as least at first glance I have…and the tell tale oily boot. I there really an issue with the standard Guzzi replacement gasket or should I be thinking about a non-Guzzi part. Any pointers regarding the job would be gratefully received. Thanks
Roy Green from the Forest of Dean
For your Griso 1100 2V, the rocker cover gasket you want is:
- Moto Guzzi OEM part no. 976139 (MG976139) – quantity 2 (one per cylinder). This is the correct valve/rocker cover gasket for all Griso 1100 2V models.
While you’re ordering parts, I’d also recommend replacing these if the covers have been leaking or if you’re doing a valve service:
-
Spark plug cover (the little plug tunnel cap): GU06023400 – quantity 2.
-
Rubber bushes/grommets for the cover bolts: GU91120617 – quantity 4. These harden with age and are a common source of oil weeps that get mistaken for a failed rocker gasket.
A few fitting tips:
-
Clean the head and cover mating surfaces thoroughly.
-
Fit the 976139 gasket dry—no RTV or sealant is normally required.
-
Torque the rocker cover fasteners gently; overtightening can distort the cover and cause leaks.
If you’re chasing an oil leak, can you tell me where the oil is appearing—bottom of the rocker cover, around the spark plug cap, or around the mounting bolts? The Griso has a few typical leak points, and I can narrow down exactly which seals you need.
at bottom of the rocker cover, around the spark plug cap.
If the oil is at the bottom of the rocker cover and around the spark plug cap, there are two likely culprits on the Griso 1100 2V:
-
The rocker cover gasket (976139) – oil runs down the bottom edge of the cover.
-
The spark plug tunnel seal/cap (GU06023400) – oil seeps from around the plug cap and then runs down, making it look like the rocker gasket is leaking.
On these engines, the plug tunnel seal is often the actual culprit, especially if the leak seems to start around the spark plug cap itself.
I’d suggest ordering:
-
2 × MG976139 rocker cover gaskets
-
2 × GU06023400 spark plug tunnel seals/caps
-
4 × GU91120617 bolt rubber grommets
It’s inexpensive insurance, and then you’ve renewed all the usual leak points in one go.
A couple of checks before ordering:
-
Remove the plug cap and look inside the spark plug recess. If there’s oil pooled around the spark plug, the plug tunnel seal is definitely leaking.
-
If the recess is dry and the oil starts at the cover’s lower edge, it’s more likely just the rocker cover gasket.
Also inspect the rocker cover itself for any slight distortion around the bolt holes from previous overtightening—it’s uncommon but can happen.
How many miles has your Griso done, and has the leak started recently or has it been weeping for a long time? That can help narrow down whether the rubber seals have simply aged out.
I had the same problem with my 2 valve 1200 sport after a spirited ride down to the mandello open day a few years ago. The gasket appeared to have been sucked into the engine causing the rocker cover to leak. Could’ve been due to the cover bolts not being tight enough but they seemed ok. I bought new gaskets from Agostini’s in Mandello that are rubberised aluminium rather than just paper and never had a problem again.
I still have a couple I can send you if you’re interested? I won’t be needing them
Gerard
This is Chat GBT’s answer. Seems reasonable.
For your Griso 1100 2V, the rocker cover gasket you want is:
- Moto Guzzi OEM part no. 976139 (MG976139) – quantity 2 (one per cylinder). This is the correct valve/rocker cover gasket for all Griso 1100 2V models.
While you’re ordering parts, I’d also recommend replacing these if the covers have been leaking or if you’re doing a valve service:
-
Spark plug cover (the little plug tunnel cap): GU06023400 – quantity 2.
-
Rubber bushes/grommets for the cover bolts: GU91120617 – quantity 4. These harden with age and are a common source of oil weeps that get mistaken for a failed rocker gasket.
A few fitting tips:
-
Clean the head and cover mating surfaces thoroughly.
-
Fit the 976139 gasket dry—no RTV or sealant is normally required.
-
Torque the rocker cover fasteners gently; overtightening can distort the cover and cause leaks.
If you’re chasing an oil leak, can you tell me where the oil is appearing—bottom of the rocker cover, around the spark plug cap, or around the mounting bolts? The Griso has a few typical leak points, and I can narrow down exactly which seals you need.
at bottom of the rocker cover, around the spark plug cap.
If the oil is at the bottom of the rocker cover and around the spark plug cap, there are two likely culprits on the Griso 1100 2V:
-
The rocker cover gasket (976139) – oil runs down the bottom edge of the cover.
-
The spark plug tunnel seal/cap (GU06023400) – oil seeps from around the plug cap and then runs down, making it look like the rocker gasket is leaking.
On these engines, the plug tunnel seal is often the actual culprit, especially if the leak seems to start around the spark plug cap itself.
I’d suggest ordering:
-
2 × MG976139 rocker cover gaskets
-
2 × GU06023400 spark plug tunnel seals/caps
-
4 × GU91120617 bolt rubber grommets
It’s inexpensive insurance, and then you’ve renewed all the usual leak points in one go.
A couple of checks before ordering:
-
Remove the plug cap and look inside the spark plug recess. If there’s oil pooled around the spark plug, the plug tunnel seal is definitely leaking.
-
If the recess is dry and the oil starts at the cover’s lower edge, it’s more likely just the rocker cover gasket.
Also inspect the rocker cover itself for any slight distortion around the bolt holes from previous overtightening—it’s uncommon but can happen.
How many miles has your Griso done, and has the leak started recently or has it been weeping for a long time? That can help narrow down whether the rubber seals have simply aged out.
Hi Gerard, thanks for your reply. The bike has done only 20000 miles but it suddenly leaked quite spectacularly on the way to work last week. From memory I was giving it a bit of stick for a change and yes, I would be very glad to have the Agostini gaskets. If you are happy to email me your bank details I’ll send you whatever you’d like for them plus postage of course. Could I also ring you sometime this week as I’m going to take the cover off tomorrow and could then describe to you what I see. My phone number is 07956 765600 and email rtggreen@hotmail.com. Thanks again Roger. (‘Roy Green from the Forest of Dean’ is just a nickname that a very good friend gave me - sadly he is no longer with us)
No worries Roger, I’ll give you a ring tomorrow, had a few beers what with it being Father’s Day n all 
You can have the gaskets though, don’t want anything for them, happy to help another Guzzisti, just need your address.
Bet my answer was a relief after all that Snapchat nonsense what a load on boll&x!