1982 gpz 750 brakes

I have bled the front brakes, soft lever. almost to the handlebars before any pressure on lever. no air out of calipers no leaks at banjo fittings or hoses. I'm at a loss, never had this much trouble with bleeding brakes. Tried every trick in the book. any ideas? Rear brake was no problem at all.

What if anything have you done to the brakes? Have you ever torn down the system to clean out the crud?

Yes, from master cylinder to calipers, removed pistons and cleaned calipers and pistons. Actually pretty clean, checked and cleaned banjo bolts and checked orifices. cleaned pistons some pitting, but not leaking fluid at calipers. I have brake lever tied to handlebars will check tomorrow to see if there is any improvement.

I have been having the same problem for some time now. Bled them at least 6 times. Reverse bled them. No change. I am going to try a method I read on another forum. Disconnect from the master, remove air from lines , reconnect to master and try to get a firm brake. I even changed 2ea masters. I will be watching for your results. I will let you know if I have success as well. Good luck.

Hi to both of you, have you cleaned the seal grooves out? I spent mucho coin on my brakes , trying different calipers master cylinders and linesbefore being advised by a moto morini guru to get my grooves cleaned . he was correct no problems since.

Sponginess at the lever is typically because the caliper pistons have parked too far back into the caliper body. You need to get them to move closer to the rotor. Tying back the hand lever against the handlebar is to increase pressure in the system for a long period of time. With the lever tied back over night the caliper pistons will (hopefully) slowly creep closer to the disc, and eliminate or at least greatly improve, the sponginess. Needless to say you have to make sure the master cylinder and calipers are clean, particularly the small return port in the master. Fresh brake lines, hopefully some teflon/stainless braided type, are installed too. They don't expand as much as rubber lines and provide a more firm level feel.

Have you tried a vacuum bleeder?

+1

I had a difficult one recently, I removed the caliper and tapped the hoses and caliper body with a screwdriver and lifted it up to help the bubbles float to the top. Bingo, a couple of big bubbles and sorted.

If you very gently squeeze the brake lever you can let a some bubbles out, then button it up, bounce around on the forks, lean it from side to side and repeat. Put a cover over your tank and clocks as it is easy to let some brake fluid spurt out as you work the lever.

I received this message from another forum, from their moderator. I will try this method, hopefully this will work, will keep you guys updated.

The front brake bleed on a Kaw is complicated by the fact that the two lines go into a combiner and then come out with two lines. Generally, leave one bleed valve closed and use a Mity Vac on the other to DRAW FLUID THROUGH... keep a towel under the brake reservoir and keep it from going dry in the process. Thanks George! @ www.wgcarbs.com

and why is this in the ENGINE Section ??????

Reversed bled the brakes, fluid changed several times from both calipers no bubbles, noticed while depressing brake lever noticed hoses expanding, so at this point that's what I think so far. put wood blocks on calipers expanded pistons out and re-bled system same result soft lever, i does complete stop the bike but lever is almost to the handlebars.

I had the same problem on my '82 KZ750R1, new hoses solved my issues.