Hello, all. I am suffering from the exact same front brake bleeding problem. I have a 1994 Kawasaki KDX 200. The brakes worked fine, but since the motorcycle was purchased used, I thought it would be a good idea to drain and re-fill the front brakes with new fluid since I had no idea how old the old fluid was. The bike had 258 miles on it when I bought it, and I started fooling with the front brakes at 300 miles.
I have pumped out all the old fluid plus plenty of new fluid. To avoid a problem such as qwchrbeliakn mentioned, I took the front master cylinder off the bike and held it higher than the rest of the system. I believe I followed the service manual correctly to fill the system with new brake fluid. When attempting to bleed the system, I poured some brake fluid in the open master cylinder, then slowly pumped the lever a few times. The manual states that after a few pumps, the air bubbles inside the master cylinder will be bled off. I noticed that this didn't appear to be happening. After a few pumps, I noticed that if I barely pulled the lever in, several air bubbles would come up. Is this normal or not? I went ahead and screwed the cover down and tried to bleed them, but the lever would never build much pressure. I would pull it several times, then crack the bleeder valve open and the lever would go all the way in, then I would close the bleeder valve, then let go of the lever. It just won't build pressure. I would re-check the fluid level and have to add a little. I didn't run it completely out. After a few attempts and re-fills, it just won't maintain pressure.
Any ideas?
Thank you,
JasonWho