Bill Forbes always ran a Balance pipeIn period 3 racing here in Aussie (that is bikes from 1946 to 1962) you can run some types of delorto carb's but no accelerator pumps allowed. Brian I think they are for a balance pipe of some sort. I've only installed one of those top end kits on a Comet, so I blanked the fitting off with a suitable bung. The alloy tank looks good, I should have put one on the racer.......................Cheers..........Greg.
Any idea what size inside ?, Cheers Bill.Bill Forbes always ran a Balance pipe