The car runs a swiftune sw8 cam
yes split weber 45 on longman manifold
no balance pipe
As far as I remember I run the little springs from weber, what do you mean with thakeray washer? Are these the washers which look like a sort of mini spring?
And yes, it happens after thrashing around on higher revs. The engine only looses any idle speed, you can still keep it going with the throttle but under hard braking and no throttle it just dies.
How can you check that the screws are not too tight?
Thank you very much
Yes, the thackeray washers are the little springs.
The tightness of these is not an exact science I found. As I said, too slack they leak air in and too tight they foam the fuel. If they are really slack the engine will suck the O rings in too.
Hard to say the correct tightness but the thackeray washers should not be fully compressed and if you grab the air filter end of the carb there should be a tiny bit of movement where the carb rocks on the rubber O rings.
Weber may have some data on the tightness of the thackeray washers if you look on the net.
I would put my money on heat vapourising the fuel.
What length inlet manifolds are you using?
Short ones will have the carbs over the exhaust manifold so will increase the heat on the carbs thus making vapourising more exaggerated.
Might be worth checking the O rings are in good order too.