I tried to buy a new Master cyclinder from Motorworks Uk. The payment failed so I thought I woudl do it again next day. Next day the price had gone up about 6 quid - Brexit and exchange rates not doubt. They agreed to supply at the old rate although as yet I have not ordered it because I found that someone had replced the high handlebars with straight bars but had kept the 230mm long top hose needed for the high bars, just scrunched it up under the handlebar consol (pre sept 81 model). I had a new 160mm (meant to be 150mm I think) steel braided pipe made locally and hey presto brakes fixed - no more pumping required. In between all that I had honed the master cylinder as the bike had been sitting for 6 years and there were some signs of corrosion - the hone barely changed the cylinder diameter, the bore was perfect and the old piston works fine but in actual fact I think that top hose was the real problem.