I have an 01 F4i and since a couple of months I have this problem with my brakes. When I start the bike and get going, the brake lever is soft and i can almostly squeeze it all the way before i achieve a good braking effect. After plunging the lever a couple of times , the lever gets to its normal self (it gets hard and i can achieve maximal braking with just minor pressure with my finger) As soon as i spend a minute or so not using the brakes, the lever becomes soft again. I did bleed my brakes but the problem remained there. Do you think that upgraing to the SS lines will solve the problem?

Thanks
Chris

 

sounds like air in the line or your rubber hoses begining to flex too much. Try bleeding them again (just to make sure) and if that dont help, i would change the lines

 

If bleeding the lines again and you are sure that the rubber lines are fine with no leaks, your master cylinder may be leaking internaly.

 

Check your seals around the calipers behind the pads as well. Look for residue on pads . Find this problem in a hurry before you need to quick brake and plant your face on the side of some assbags car that pulled out in front of you. This ones about as serious as it gets.

 

i hear you raft!

we will soon be going overland for a 2 week trip with the bikes and i really want to sort it out now. The brakes never failed me actually... I can always get as much braking as i need, even emergency braking. However i got really fed up to find a stiff lever and a second later the lever is soft like a baby's ****

 

yea if there is no fluid leakage and the fluid is new...and you've gotten all the air bubbles out...then the problem would lie in the MC not being able to hold pressure.
either rebuild or replace.

 

Could also be a warped rotor pressing back the pistons.

 

his symptoms aren't consistent with that of a warped rotor. he keeps losing brake pressure...it would build up and as it sits, it slowly goes.

 

Sounda like master cylinder to me, had the same thing happen on my car. Replaced the master, bled the brakes and all is good.

 

thanks for the quick reply guys!!

so u think it is the master cylinder ey? I will have a look at the manual to see what a rebuild involves. I will try and rebleed them again and if that doesnt work i will rebuild the MC. If still no luck, SS lines would be the last think to replace (apart from the calipers)

Thanks guys