G'day All, After reading a lot of previous posts on brake bleeding, have just spent about a lifetime trying to bleed the  brakes on the 86 K100RS aka the yellow beast. The reservoir on the MC was drained for repairs, installed but no luck in bleeding. Took up Rickmeister's suggestion of draining fluid right through the system by leaving both caliper bleeding screws open. this presumably ensured that the brake lines were filled with fluid and no air in the lines. Followed the Clymer instructions on bleeding ( after all everything else has failed) but still no luck.
Got some advice from my local mechanic who bleeds the MC by gently tapping the brake lever until all air bubbles have gone. Tried it and bingo, brakes bled in about 10minutes.
Feel better now that a new bit of information has been learnt. Cheers Tom

G'day All again, forgot to mention the MC piston must be pointing upwards. I put the bike on the sidestand for this. Worked a treat. Cheers Tom

That wont work with the ABS equipped bikes. The banjo fittings will sometimes hold air bubbles and it can be very difficult to dislodge them and that technique can help.

You got a good result in the end Tom, well done.
I always bench bleed M/cylinders before I fit them, a habit I've gotten into.
I worked for a brake and clutch supply company, and we had to bench bleed all m/cylinders prior to fitment.

a good win tom

put it in the memory banks for all us In the  future

Thanks for the info Rick and Smithy, Yep, good result in the end - just about given up - was turning blue in the face from sucking and blowing brake fluid.... Going to attack the rear brake next - should be much easier. Cheers Tom

Using this metod everytime when doing work on front masters,
(changing piston and cleaning bores) and it have been plenty of 20 mm's .
Emptied only reservoir and bore, refill reservior...turn handlebar full left,
move a bit to change the angle while getting the air out...loosen the clamp
around the handlebar so the MC angle also can be varied in that direction.

Start with long strokes on the lever, veeeeeeery slowly...it comes plenty of
air up inside thre reservoir in the beginning.
When it coming less bubbles (and it's very thiny ones) use shorter and shorter strokes.
When it seems to be no more air...vary the length of the stroke and area
along the bore...also vary the angle at the MC....it always comes a few
more tiny ones.......continue untill you are shure all air is out.

You can see the tiny bubbles inside the two small ports in the bottom of
the reservoir....when getting close to finish, it's often that it takes several
small strokes with the lever before the bubble you see in the bottom of
the port(s) comes loose.

hey Tom. Glad to hear you're getting that yellow beast into shape. Will hopefully be down your way sometime next month after easter. Hope to see it on the road for a run.
Cheers

After I finish bleeding the system, I put the brake under pressure and lock the brake lever in this position for the night.
The next morning, when I release the brake lever, I always find that the last bubbles of air have made their way to the MC.

CF

I like to add a bleed screw to the banjo bolt at the top of the tube that passes through the steering column on early K's.

All in the interest of getting rid of every last bubble.

Paul.

G'day All, thank you for all your input which will be stored in my ever diminishing memory bank. Thanks heaps. Cheers Tom