1967 Spitfire MKlV Fuel Tank Capacity and MPG

[Big Phil]

Hi,
   I have a 1967 USA Export Spitfire MKlV which I have only covered 500 miles on and so far have only filled with a maximum of 7 or so litres of fuel from near empty. I always had it in my head (from where I no not) that these tanks held 2.20 imperial gallons but I noticed today in the general data of the workshop manual it states 2.25 US gallons or 10 litres. However 2.25 us gallons is only approximately 8.5 litres. So can someone please kindly confirm what the exact fuel capacity is for the USA tank.

Also out of interest my bike is fitted with Amal premier carbs but still running on points. I am getting 67 mpg on a good run (50 miles plus) but as it's only covered 500 miles I'm still running it in and not exceeded 60 mph or 4K revs. What sort of mpg are others getting?

Regards
Phil

[ChrisG]

60-70 mpg is about right for an A65 so the Premier Carbs are doing their job well. I always fit a new Premier on my BSA's as no matter what you do to an old carb, the slide bore will be worn and unwanted air will get around the slide. Also, more likely than not, the pilot jet which is inaccessable will be partly blocked and no amount of carb cleaner down the tube will clean it out. The removable jet on the Premier is a godsend!
As most of the time when at cruising speed, the throttle position is in the 'Pilot jet'area on the Amal info i.e., the area we use the most.

[Big Phil]

Thanks for the reply Chris and it's good to know the mpg is at the higher end of what I could expect. When I first got the bike it had the original concentric carbs and was only achieving 50 mpg and l couldn't get it to tick over consistently once it got hot. On stripping the carbs down I found the slides were sticking at high throttle opening's but slack at mid point and below. So I decided to change to new premiers as the concentric were clearly worn out and not safe to use at high throttle openings. Luckily as I am running the bike in I hadn't opened the throttle past half way so avoided any safety issues with the slides sticking wide open!