cannot see the 357 listed for the A7SS in the parts book for 1960. It kept the same valves, springs collars and collets as the iron head and was listed with 8:1 compression.

The US market got 8.5:1

from my limited experience with an a65 spitfire. i found the highly tuned motor was very fussy about carburation. the new amals have removeable pilot jets and thats the direction i would go in.
check your spark with a strobe. if you have points are they insulated properly or sticking?

Hi,

Checked battery; ok.

Not done a compression test, but it feels ok.

Plugs look like it is running rich; same both sides.  More than likely because I am struggling to set the carbs up due to missing/poor running.

Doesn't appear to be passing oil.  Although I think I need to take the head off and change guides and valves.  The bike had been laid up for a long time (or so I was told) prior to me buying it and I wondered if sticking valves could be due to that. Especially as I had previously bought a bike that had been laid up with a similar misfire problem.

Dave

Hi Mike

I think a 3.75/4.00 is 110/90

 
 What is the eqivilant metric size of a 4.00 tyre.

Mike