Re: timing chain engine idle question

[PGAHOWELLS@domain.elided]

Hi
If you start the engine, and then take off the filler cap and the engine note
does not change you have an air leak. The valve cover is connected to the
carbs, so lifting the oil filler cap lets in much air.
If the engine note does change then no air leaks. 
Since its getting so hot so quickly it may be your timing is far out or
mixture too weak.

I don't think it is your airbox valve but thats just my view.

If you take off the oil filler cap and look down there with a very small
magnalite torch, you can see the chain tensioners. You can also see the little
hooked back plate. The hook part stops the tensioner coming out of its
housing. If you tensioners are close to the hook  (1/16 inch) then chains are
almost at full stretch. If you have 1/2 inch clear which I had when last
looking, you don't need to change them. 

Good luck

Peter H