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  #11  
Old 07-03-18, 15:39
asklepios asklepios is online now
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Understood. One certain thing from the exercise is that your current gaskets are suboptimal so you could hardly be worse. Colour Tune...have two sets still in my garage.

Ethanol was my first thought but wiser heads have discounted. They look carbonised to me. Too much heat? Backfiring through the carbs?? Keep us appraised.

Last edited by asklepios; 07-03-18 at 15:40. Reason: typing
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  #12  
Old 07-03-18, 15:48
Lolat492 Lolat492 is offline
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Will do.
Atlas must be reading this thread, as 5 mins after posting my latest they emailed me!
They need to talk to me before quoting etc.....not a good sign, but they understand and have a solution.
Will call them tomorrow, but ready to cut my own now.

This latest failure is exactly what happened 3 years ago, same supplier, same gasket type.
I have the same engine in my classic 911, engine made in 1985, never been apart and running the same fuel as the hillclimb engine except on injection and engine management all Porsche.
130K miles and still perfect.

Porsche of course do not make the right gaskets for these carbs.
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  #13  
Old 07-03-18, 19:08
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Why not just RTV and be done with it?
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Working on increasing my carbon (fibre) footprint
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  #14  
Old 07-03-18, 19:54
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redturner37 redturner37 is offline
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Graham, isn't there anything in he Weber DCOE range that will fit, maybe some Mysabs. I may have a few that you could try without having to buy some...
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  #15  
Old 07-03-18, 20:52
Darvie Darvie is offline
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When i said viton i was referring to "O" rings, just to clear it up so as not to send some one up a blind alley.
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  #16  
Old 07-03-18, 21:47
Lolat492 Lolat492 is offline
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Silicon is possible of course, but messy and tricky to 'un-seal' as the contact surface is quite large, but a possibility.
The issue for a simple O ring is the irregular shape of the port in the head. The port in the manifold is circular, but the head has a 'half-moon' cutout to allow the injector spray to entre into the inlet tract, thus an O ring on one side is easy, other face very tricky.

The paper gasket is a simple and serviceable approach.

Time is running out too, Loton is a few weeks away which is why I'm looking to DIY the paper gaskets hopefully tomorrow.

When fresh, the double gasket design is very good. This set of USA gaskets were fine until the tail end of 2017 when the odd pop and bang started to appear on the one side of the engine, the side with the leak.
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  #17  
Old 08-03-18, 07:59
Hillman Hillman is offline
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[QUOTE=SteveSlowboy;146937]Why not just RTV and be done with it?

My (limited) experience of RTV is that it is good with oil but breaks down when exposed to petrol.
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  #18  
Old 08-03-18, 08:18
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redturner37 redturner37 is offline
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The inlet manifold on my Zetec, on carbs has never had a gasket fitted since I installed the engine, just RTV. I use the same fuel as you Graham....
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  #19  
Old 08-03-18, 15:02
Lolat492 Lolat492 is offline
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Just to bring this little saga to a happy finish:

Cut the paper gaskets today using two of the 6 plastic heat insulators as a cutting jig, worked a treat, and 30 mins later all 12 were done.
Having a scalpel-sharp Xacto modelling knife worked wonders.
The 2 x 8mm dia stud holes were cut using my hole punch which was a god send in the task.

Cleaned the surfaces and rubbed the plastic sealing faces on some fine W&D paper on a good flat surface to remove any high spots and to roughen the surface a touch.
Assembled the lot and fired the engine up...

Fantastic!
Sound great, the pulses coming from the twin silencers are as even as can be, instant throttle response.
Just to be sure, I sprayed some brake cleaner on the spot that was leaking, no a slightest of engine tone change.
All cylinders now at '5' on the meter scale across all 6 pots.

Job done, if only I could get the little 2 stroke engine to run (at all) in my 1950 French motorcycle the world would be perfect.

Thank you all for your help and suggestions.

I am now actually ready for the practice day at Loton!
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