What pisses me off today is CB750 front brake master cylinders. I installed a kit in one awhile ago on Ken's K1, then for the last couple of weeks, I've bled up the brakes, but had no lever pressure. Bugger.
Today I found another MC, installed another kit, bled it up, still no joy. Turned out both MC's had blocked breather holes, and they were blocked so bad I had to use a jet drill to unblock one. As soon as I did though, I had pressure, and it took me just five minutes to bleed them.
I suppose it really pisses me off is that it took me so long to realise what was wrong, I've only been playing with these old buggers for 34 years!