I just completed a total strip down and repair of the twin disc system om my 1988 BMW.(MC on the handlebars)
I rebuilt the callipers and master cylinder and changed to twin braided lines with a double banjo at the MC.
I was having trouble building pressure with a totally empty system so I used 2 long clear hoses pushed onto the bleed nipples, they were long enough to go higher than the MC.
I opened the bleed nipples and filled the MC with fluid, topped up the MC a few hours later then left it overnight, the next morning the fluid in the clear hoses was sitting at the same level as the fluid in the MC.
I shut the nipples, topped up the MC and then bled the system of the little air that was left just as you normally would.
It only took a couple of pumps this time whereas I had tried for a hour before with no good result.
Some of the 19 rides in my shed
2014 V2, Snoopy
2009 Wee, Pumbaa the pig
WR450F, The Blue Postie Bike
YZ250N smoker with rego, Stinky.
Yamaha MT09 (FZ09), The Scud missile.
Club Lead not Club Med.
He with the most toys wins.
Out of my depth in a puddle.
Live life on the edge you will see more that way.
Ridding a motorcycle keeps things in balance.
At the end of each trail and at the end of each day history is made.