Inlet venturi coked up

[Woody850]

I have taken my Premiers off to clean them for the winter and also removed the inlet stacks.
Peering down the inlets in the head with the help of a mirror I see that the left cylinder has
what looks like a build up of black coke. Going over to the right cylinder it is even further up
the inlet.
Is this a sign of the valves not seating properly, I do not think it is normal.

 

[baz]

Do you have a fiberglass tank?
Any sealent in your tank?
Are your fuel pipes intact?

 

[Woody850]

Do you have a fiberglass tank?
Any sealent in your tank?
Are your fuel pipes intact?

The fibreglass tank was ditched about three years ago and the new one has no sealent,
as for the fuel pipes I use the green Italien types.

 

[Schwany]

Compression test should give you a clue about the valves not seating.

 

[swooshdave]

Picture?

When you switched from the fiberglass tank did you check the inlet then?

 

[Tornado]

Can you see the valve top sides and a bit of the stems? Mine had a coking build up. I ultimately had inlet valve seals failing and replaced. Later after getting left side misfires, ultimately determined the oil drain passage on the rocker inlet box floor was partially blocked, leading to oil getting drawn into inlet ports and fouling valves. Unblocked the passage using a long wire down the opening to timing chest. Oil then draining better. Ran some Seafoam into running engine and it did clean valves up somewhat.

Recently lost the head gasket so now its getting new valves/guides and seat work.

 

[Esmerela]

I have taken my Premiers off to clean them for the winter and also removed the inlet stacks.
Peering down the inlets in the head with the help of a mirror I see that the left cylinder has
what looks like a build up of black coke. Going over to the right cylinder it is even further up
the inlet.
Is this a sign of the valves not seating properly, I do not think it is normal.

I would take a look at your valve guide oil seals, sounds like oil could be getting by and travelling down the valve stem.

 

[Woody850]

When you switched from the fiberglass tank did you check the inlet then?

Unfortunatly not!

Pictures will be coming but first I must update my VIP Membership.

None the less I thank you all and I hope I get to the bottom of it.

 

[swooshdave]

Unfortunatly not!

Pictures will be coming but first I must update my VIP Membership.

None the less I thank you all and I hope I get to the bottom of it.

In the meantime you can just use another photo hosting site.

 

[Woody850]

Well here are the left and right venturi, the right being the worst of the two.

 

[Torontonian]

I agree , likely your valve seals are toast . Try fitting the Kibblewhite type , after the clean up of course.