Finally have spongy front brakes

[Dopey]

After years of reading everyone's posts about spongy front brakes and thinking how lucky I am thai mine seem to be sufficient I went to ride today and noticed the lever dam near hitting my throttle. I have always noticed it was a little soft but nothing like what some have written about and I was always able to stop with the lever hitting no more then the half way point, and if necessary I could always give it a quick double tap and have a full lever. Im obviously going to try and bleed them first thing as I can say they seemed just a little different when I changed my pads and bled them a couple months ago so I'm hoping maybe an air bubble made its way thru. But if this doesn't fix the issue what all lines will I need to change for thre front bakes? I will keep the abs and I believe it was @ottafish that said he used a "hybrid" kit that kept ther factory hard lines and I would like to be able to do something similar and replace as little as possible since I just put new tires on and am trying to get a new helmet and possible windscreen and would like to stay married . Any suggestions are appreciated , EXCEPT to upgrade the master cylinder because while I will one day that would probably get me worse then divorced

 

[ItsDooomz]

Hayabusa ABS brake lines are fairly simple. The front brakes have two lines, master cylinder to ABS unit and ABS unit to calipers. They're a hardline pain in the ass. I replaced one of the rear lines from the ABS unit to the caliper when I did my extended swing arm. I have since gutted all ABS components.(C10 mod) It's a drag bike so I don't need ABS or extreme heat cycle performance and the Busa ABS system is archaic at best anyway.

 

[Berlin Germany]

@Dopey

what busa are we talking about ? gen1 or 2?

1. bleeding the brakesystem - at gen1 AND gen2 - best idea is to replace the short hose (fender crossing) by a long one, connected to the master by a doubble screw. by this every little bubble can climp up to the masters reservoir and air won´t be an issue any more. when changed tie the lever close to the handle for about 3-4 hours - the resulting pressure in the system causes even the smallest bubbles to rise (impssible when staying at the fender crossing "system")



2. gen1 - dismantle the calipers completely and do the deep cleaning
here some pure horror pics of a gen1 caliper i opened yesterday.

see the dirt in the notches where the seal sit - horror
here the notch of the small piston´s dust seal .

this little hill of dirt i put put of only one! caliper (6 piston´s notches)

3. gen1 + gen2 - eventually replace the rubber seals inside the master - sometimes they "quit their job" and let pass back a little bit of the dot4 into the reservoir.

 

[rubbersidedown]

Might be a good time for a full inspection Dopey. Mr.Berlin has a good idea with changing out the lines. Aftermarket lines such as Galfer or similar skip the connecting line between the 2 front calipers.High end aftermarket lines are better than stock as they don't expand with the squeezing of the lever.Good time for some high performance pads too.EBC HH or similar. As stated above the lever to grip method works good,but I'm an' impatient bastid and use a MityVac pictured below for bleeding and many other uses.Sucking old fluid out of masters instead of rags,testing vacuum,etc.
Rubb.
The generic one...vac bleed
The Real one,newer version than mine...vac bleed,twice the price

 

[ottafish]

PM sent

 

[Dopey]

Might be a good time for a full inspection Dopey. Mr.Berlin has a good idea with changing out the lines. Aftermarket lines such as Galfer or similar skip the connecting line between the 2 front calipers.High end aftermarket lines are better than stock as they don't expand with the squeezing of the lever.Good time for some high performance pads too.EBC HH or similar. As stated above the lever to grip method works good,but I'm an' impatient bastid and use a MityVac pictured below for bleeding and many other uses.Sucking old fluid out of masters instead of rags,testing vacuum,etc.
Rubb.
The generic one...vac bleed
The Real one,newer version than mine...vac bleed,twice the price
View attachment 1621208

@Dopey

what busa are we talking about ? gen1 or 2?

1. bleeding the brakesystem - at gen1 AND gen2 - best idea is to replace the short hose (fender crossing) by a long one, connected to the master by a doubble screw. by this every little bubble can climp up to the masters reservoir and air won´t be an issue any more. when changed tie the lever close to the handle for about 3-4 hours - the resulting pressure in the system causes even the smallest bubbles to rise (impssible when staying at the fender crossing "system")



2. gen1 - dismantle the calipers completely and do the deep cleaning
here some pure horror pics of a gen1 caliper i opened yesterday.
View attachment 1621203

see the dirt in the notches where the seal sit - horror
here the notch of the small piston´s dust seal .
View attachment 1621204

this little hill of dirt i put put of only one! caliper (6 piston´s notches)
View attachment 1621205

3. gen1 + gen2 - eventually replace the rubber seals inside the master - sometimes they "quit their job" and let pass back a little bit of the dot4 into the reservoir.

Mine is a gen 2 which is why I said I wanted to keep the abs, I didn't do a full rebuild but I did just go thru and flush the fluid and replace the pads a couple months ago. @rubbersidedown I'm impatient as well and being a mechanic by trade I have a mighty vac in the arsenal and used it when bleeding them . Im gonna give the lever tied back thing @Berlin Germany suggested a try when I bleed them this time as well. Im looking at getting the coremoto lines for the front right now I just have to free up some cash to do so which isn't the easiest thing to do with 3 kids and this crazy rona world we are living in. Appreciate the help as always fellas.