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V7 Ingesting Oil on Trailing Throttle

JasonC

JasonC

Cruisin' Guzzisti
GT Contributor
Joined
Jun 5, 2021
Messages
371
Location
Katy, Texas
My 2010 V7 Cafe with a big-bore kit has been consuming oil on trailing throttle for some time now. This is a classic symptom of worn valve guide seals, which seems premature as this bike has less than 9,000 miles on the clock. However, I pulled the valve cover hoping I could remove the valve springs with the head in-situ to access the valve seals, but I didn't have a valve spring compressor small enough to fit the valve train area.

So off came the cylinder head. A quick inspection of the head gasket suggested that the oil leak path was not the valve stem seals after all, but a ~5/16" area on the lower portion of the head gasket; see pic.

Question: Does the big-bore kit (820cc I think, I was not the installer) require a special head gasket, or will the OEM gasket work?

Thanks!

Jason
 

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JasonC said:
Does the big-bore kit (820cc I think, I was not the installer) require a special head gasket?
Click to expand...
Yes it does. I didn't develop, sell or have anything to do with the parts or disaster of an installer who did the bike originally. I had some custom all-metal gaskets made originally for my kit offerings here, but then the (older) V9 (84mm pistons) was released with all-metal gaskets, I switched to them. They used to offer different thicknesses. Just be sure to check piston to head (and related) clearances and compression.
 
GTM® said:
Yes it does. I didn't develop, sell or have anything to do related to the disaster of an installer who did the bike originally.
You can use the older V9 all metal gaskets. They used to offer different thicknesses. Just be sure to check piston to head (and related) clearances and compression.
Click to expand...
Thank you for that information.

I looked up gaskets for a V9 Bobber 2016--2022 is this old enough? Notably the gasket that was installed was fiber and metal, not all metal and it measures 0.045" / 1.143mm thick.

There are three (3) Bobber gaskets listed: 1A004660, 0.6mm thick; 1A004661, 0.8mm thick; 1A004662, 0.1mm thick (I think this is a misprint and should be 1.0mm thick.)

None of the Bobber gaskets are as thick as the gasket that was installed.

Do the aforementioned part numbers sound correct for an 820cc application?

Jason
 
JasonC said:
Do the aforementioned part numbers sound correct for an 820cc application?
Click to expand...
Can't say. I developed my pistons for both all-metal OE base and 1.0 mm head gaskets (you are correct on the typo).
 
I infer from your riposte that you use the 1A004662 gasket for your big-bore kits?

If so, that sounds like a good starting point for me and I'll do the clay test to check for any valve clearance issues.

Jason
 
JasonC said:
I infer from your riposte that you use the 1A004662 gasket for your big-bore kits?
If so, that sounds like a good starting point for me and I'll do the clay test to check for any valve clearance issues.
Click to expand...
Correct, and you won’t have any valve clearance issues on the reverse dome pistons, only possible piston to head as stated above.
 
GTM® said:
Correct, and you won’t have any valve clearance issues on the reverse dome pistons, only possible piston to head as stated above.
Click to expand...
Well, I installed the 1A004662 head gasket (V9 Bobber gasket) and all seems good so far. The gasket that I removed was made by Cometic and has a published effective thickness of 0.043", whereas the V9 gasket appears to have a compressed thickness of 1mm or 0.0394". The difference between the two is only 0.0036", so I don't think I'll have a clearance issue. I checked valve clearance with clay and have in excess of 0.1" on both valves. Regarding piston-to-head clearance it appears that the pistons stop short of the head by over 0.06" so I think I escaped a clearance issue there, too.

Thank you for the head gasket suggestion, Todd.

Jason
 
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