Have you tried this? I've posted this before so this time I'll just copy it here.
BLEEDING BRAKES.
I've been working on bikes since before they had disc brakes. I usually drain & refill mine at least once a year so I've had lots of practice.
I get a length of 3/16" clear tubing long enough to reach from the bleeder screw to the master cylinder. I fill the m/c, put the hose on the bleeder screw & open it about 1/2 turn & hold the free end of the tubing in the fluid in the m/c reservoir. Keeping the free end down in the fluid, I slowly pump the brake lever until I have a solid stream of fluid in the hose. I then close the bleeder screw & remove the hose from the bleeder. If you clamp the hose just above the bleeder before you take it off, you won't even make a mess. This has always worked for me & gives the firmest lever of all the methods I've used for years. It works because when you release the lever, it will draw fluid into the hose & not air, & when you squeeze the lever the air will bubble out. Just keep the free end IN THE FLUID so you don't draw air in.
Between my 2 bikes & my friends, I do this several times a year. It even works for rear disc brakes too, as I found out when I did my V-Star 950 the first time.
I first came up with this idea in 1980 when I put a disc brake front end from a '72 Norton Commando on my '70. After spendng a frustrating day going through the m/c & caliper, cleaning & rebuilding both, I still couldn't get it to work. I tried this & was done in 15 minutes. You don't forget what works when you've been as frustrated as I was that day.