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Great video.

Spitting from the carbys at the rpm you had (about 3000 rpm) tells that the idle circuit is lean.
As you noted,unscrewing the idle mixture screws helped.
Just a thought,,go up 1 size in the idle jet.
Hopefully the idle mixture screws will be out about 1-2 turns from the bottom.
If the idle mixture screws are out more than 4 turns,means that the idle jet is too small.
The video tells that the carby syncronisation is pretty close,so just play with the next size up= idle jet.
Tell us how this goes.
No,you dont have a burnt valve at this stage,but a compression test will tell all.
If you had an exhaust analyser,that can tell lots also,but after 30 odd years of playing with carbys,my ears tell me the most.
To get the best out of it,after you sort out the idle jets,put it on a chassis dyno,with an exhaust analyser up the exhaust to get the best out of the engine.
By the way,where is the engine breather pipe going to now ?

Robert
 

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The more turns out (over 2.5 )on the idle mixture screw generally means that the idle jet is too small.

The hesitation when having to pump the throttle to make it run better usually means the accelerator pump jets are not squirting.
Remember,when adjusting carbys,make sure you do it at engine operating temperature.
Or at least,make adjustments to get it to engine operating temperature,and then do all final balance,idle mixtures and idle.
It all just opinions,but we can only help with solutions with what information we have.
The video tells me that the idle jets are too small,or the idle mixture screw need turning anticlockwise.If the idle mixture screws are out too far=more than 3 turns,the idle jet is too small.

Robert
 

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hi again Espresso Veloce Tim.

I did start by writing about my opinion and others opinions but deleted it.
I prefer to start with the easy way,by richening the idle circuit,then evaluating from there.
I promice not to add any more to this topic.
Good luck.

Robert
 

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Im still here.

I would not follow Roberts advice if all is good now= no spitting.
But usually,idle mixture screws wound out more than 3 turns GENERALLY means that the idle jet is too small.
If you feel it is running lean between idle and 3000 rpm,and at cruising,you know what to try.
If its all good now= leave it alone.
Sorry about my previous comment,but I usually start with the easy things first,and then look for the problems.
Here in Australia,for some reason,I am putting in bigger idle jets and it USUALLY fixes the problems.= spitting
Remember,,all tuning is done at engine operating temperatures first.
Then play with idle circuits
Cars require a richer mixture when starting,like using the choke.
By all means= check tappet clearances and cam timing,and compressions and point gap and timing,etc,but the start of this thread said = everything was good before.

Robert
 
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