i've spent most of the day dodging raindrops and trying to get firm brakes on the cb900.
i've bled and bled till my hands cramped but i still can't get a firm lever/pedal.
The fluid seems to be coming through clean and free of air bubbles anyone got any tips?
i seem to have got a little rusty in this dept!!!
thanx guys...

There's two tips I've heard on bleeding, which might be useful.

One is to remove the caliper and tie them about the height of the master cylinder. Since the bubbles want to float up, its easier to bleed them this way.

The other way is to tie back the brake lever and leave over night, to try and let the bubbles make their own way out.

try what davie suggests, have you checked the master cylinder seals?

the ms seals seem ok, i've clamped both front and rear levers wide open for the evening we'll see how things are in the morning.

Fit goodridge hoses or new brake lines. They made a massive difference to bikes I've owned.
I was going to suggest clamping the levers back before BD beat me to it, that's worked for me.
I used a brake bleeding kit from HALFORDS before to sort out a brake bleeding problem on a car. It uses air pressure from an inflated tyre to force the fluid through.

I just noticed the bit about you dodging rain drops, brake fluid absorbs moisture

Ima
had the same problem on a cbr1000 I had some time back,it took me three weeks to sort it even after contacting honda who had no idea.

In the end it was simple.....

The person who owned the bike before me CHANGED THE C/LEVER TO A PATTERN TYPE and the difference was the hole where the m/cylinder push rod enters, IT WAS TO DEEP and not allowing the push rod to be fully pushed in.

It may not then again? it could be the prob, so check the depth of the f/brake lever to see (if thats an original) and see if the hole depths tally.

All I did to correct it was cut the end off a bolt as a distance piece and slip it into the hole n' BINGO prefick..

Yes I agree with most of these tips. I too have tried a cheapo kit from Halfords, - basically it is a one way valve with a container to collect the old fluid. Works fine on my old Golf after pumping the pedal a few times and saves the hassle and danger of snapping off the nipple. Can't think why it will not work on a bike when replacing the fluid with new - incidentally the old stuff should be much darker so you should know when it has all been pumped out.

I have had this problem on many occasions often takeing me days to sort, i have tried all the sugestions above with varied results, the straping of the leaver back i have found most sucsesfull method, i used a cable tie.

I often try tilting the caliper and bleading at the same time, ther could be trapped air in the piston chamber.

I have also been known to reverse the flow by blowing hard down the blead hose with the nipple open and some fluid in the pipe, this worked as there was some air trapped in the splitter on the front hoses.

Sounds bizzare but it worked , but it is hard to get enough pressure to force the fluid back up. Dont forget to tie the leaver back to alow flow and watch the resevoir as it refills.

I would be ready to kill the previous owner!!

Another tip that works sometimes, is to tap the lines, master cylinder and calipers. Sometimes air bubbles cling to the internals of these. The braided lines comment, I can't agree more with!!! Did wonders on just about every bike I've used them on.

I found a car high perfomance shop that sells the lines and fittings, including pressing them on for less than half of what a bike shop charges for precut lines.

You may want to give it a try to save some money. I just bring in the old lines and fittings and they match them up. And to top it off, they were using Goodrige fittings. The lines were on a large spool.

I have found that on some bikes the braided lines make the rear brake a tad too sensitive so keep this in mind.