Gentlemen, I appreciate your assistance on what can only be described as a rather delicate matter.
Mine is 1/78'' long. The inner end has a slotted cheese head and I know it's short because the top end has been shortened by one of the two previous owners. I think they did it as felt the ensemble was too long.
I never bothered about it until I noticed a slight weep from the joint between the 'V' banjo nut and the lock-nut above it, when after 33 years off the road I put fuel in to attempt a start.
It has turned out the fibre washer at the cheese head end is letting by and presently I am filing the circumference of a metric version so it will fit in the hole just to get the beast to make noise without the fear of an inflagration.
The lack of length does pose me a problem in that to obtain the float bowl scribed line to match the bottom of the circle I don't have an awful amount of thread left to screw on the top nut onto the hanger bracket.
If any of you chaps help me out by looking at yours and describe the head and the length I will know whether mine is normal.
I do not have a drawing of an AMAL
GP carb so right now I'm working on what I see with mine only.
Thanking you in advance chaps, Graham.