Maxim front brake dillemma

So today I went to Gamuru's place to install my new front brake master cylinder and pads. What we both thought would be a short project took much longer than we planned.
The problem: after bleeding the daylights out of the lines, the lever felt squishy instead of making solid contact. The same symptom appeared using the old master cylinder as well. We can't find any leaks, and I'm sure we got all the air out. The only thing I can think of is perhaps the rubber brake lines (likely the originals) have weakened and are ballooning under the pressure of the piston. The brake works, as long as I don't need to stop quickly.
Don and April's bikes have these fancy composite lines, and their levers feel good and solid.
Anyone else have this problem?

 

You answered your question here : "the rubber brake lines (likely the originals)"

and provided a solution to your question here : "fancy composite lines"

Get chacal on the line and get steel braided brake lines.

 

steel braided brake lines:

That's what Gamuru has on his two bikes!

 

Hey guys. Jeff and I bled and bled and bled those damned brakes. The best we could get was the feeling of a firm marshmallow when squeezing the brake lever. Here's a picture of what we found in the original master cylinder:



I suspect the hoses, too. They're about the only thing left that could be bad that makes any sense.

 

Hoses are supposed to be replaced every five years, nobody ever does.

With a master cylinder looking like that, I wouldn't even ride the bike until the hoses get replaced.

 

I've already parked the bike, and I'm ordering the new lines tonight. And I owe Don about a gallon of brake fluid! 8O

 

You're getting stainless lines, right? Biggest single improvement you can make to the stock Yamaha brake.

Don't feel too bad about the brake fluid, you go through a lot anyway.

And that M/C wasn't so bad, the one on my '81 looked worse than that and PO was riding it! The stuff that came out of the caliper had lumps in it too.
Yours looks rebuildable.

(be careful once it's fixed, the brake actually will work-- I had to back off the adjuster at the bar and introduce some slack.)

 

Yep, steel lines are only $20 more than rubber. I can pop for that.
And I plan on using the new MC I got from Len. Maybe I'll rebuild the old one and sell it to some noob. :lol:

 

+1.

 

Jeff, if you decide to rebuild the old one and need it cleaned let me know. I have a friend that can get her cleaned up like new.

 

You may not need it, but you could ask Len to send you the illustrated writeup I created using his install instructions. I did my 750 a while back -- MC rebuild kit, new caliper pistons/seals (couldn't get the seals without the pistons), new pads, stainless lines, fresh banjo bolts and crush washers. Even replaced the little window on the master cylinder.

Holy crap does it stop now... :mrgreen:

 

Installed the new lines today. BIG difference!! Len sent complete instructions, very helpful.