My xs650 brakes stink.

[Bandito]

I built my xs650 last year and have put about 500 miles on it since.

I put brand new calipers on the front, all new pads, braided lines, new master cylinder/lever combo.

Everything is nice and tight, I've gone through it all... the brakes are bled and feel very solid.

BUT the brakes absolutely suck. Even for single pot calipers. The worst part about it is a vibration through the forks up to the bars as the bike comes to a stop... that last little low speed bit.

The steering bearings are adjusted right... I'm at a loss for what might be causing it aside from just garbage pads. I bought all the parts from mikes and I'm 100% confident it's all setup correctly.

Anyone got any thoughts or suggestions?

 

[xjwmx]

Have you checked to see if your rotor is warped? That could account for the "vibration" I think. I have stock brakes with braided lines and I can lock up the front wheel at town speeds. That's more than enough for me.

 

[Bandito]

The rotors seem fine, there is no pulsing at the lever during braking... aside from this funny vibe as you are coming to a halt.

 

[xjwmx]

I have an '81 basically same as your year. Mine's stock. If it's stock I don't see what else could be done except check for tightness and trueness. For fork oil I have the manual minimum amount of the the manual recommended weight...a random choice basically.

 

[Tech7]

Like XJ said. your rotor is either warped, has thickness variation, or not mounted on the wheel correctly. Easy to check with a dial indicator. Anything more than .003", you're gonna feel.

 

[gggGary]

Are you running dual disks?
Is your master cylinder bore matched to the Piston area?
See this chart: http://www.vintagebrake.com/mastercylinder.htm
A mismatched master cylinder can make the brakes feel "wooden". Be a little more specific than they suck? Do they throw you over the bars they are so powerful? (kidding)

 

[jamesgs4]

have your pads ever come in contact with brake fluid or fork oil?

 

[grizld1]

Bandito, adjusting tapered roller steering head bearings can be tricky; it's not unusual for the bearings to be loose enough to permit the shudder you describe even though you can detect no slop in the steering stem when you raise the front wheel and feel for it. For improved performance with a single floating caliper use an 11 mm. MC, remove all traces of material from the old pads from the disc with garnet paper (the kind with real sand on it--don't use metallic oxide wet-or-dry paper as it will leave deposits that will contaminate your new pads) and acetone, and use premium grabbers like Ferodo Platinum or Vesrah Sintered pads.

 

[xjwmx]

...vibe as you are coming to a halt.

I'll bet he's right that it's a steering bearing problem. If it was a rotor I think you'd feel something whenever the brake was applied, at least a car's that way, plus I think I've had your same problem due to loose steering bearings.... I still have balls and races but after I'd done some work to them and and it wore in and loosened I had a funny vibe through the bars right as it was coming to a stop, and only then. In my case I knew it was the bearings because I'd just worked on them. Snugging them again fixed it for me.

 

[Travis]

Bug and tar remover will also contaminate the pads.

 

[gentlemanjim]

These bikes have weak brakes - those single pot calipers are crap. They worked ok for me, but any other bike I've ridden is far superior. My XS400R is even worse. If you need your rotor trued up I know a guy that does great work.

 

[retiredgentleman]

The brakes on my 78SE are just excellent. I have disk brakes front and rear with stock m/c's, stock calipers and stock type pads. The rotors have been drilled to help clean the pads. I've had the odd panick stop and these brakes will lock both wheels if need be. I feel very safe on them.

If you want to know what bad brakes are................drive a vehicle (car or motorcycle )with drum brakes front and rear................now those are bad brakes.

 

[gmiller217]

If you want to know what bad brakes are................drive a vehicle (car or motorcycle )with drum brakes front and rear................now those are bad brakes.

Yeah ain't that the truth ... 77 cj5 running 33's with four wheel drum = very scary My zuk had front and rear disc, my yammy has front disc rear drum ... trying to find a rear disc setup for 16" spoke wheels ... not having much luck with that but I would rather stick with drum brakes than go alloy (purely from a cosmetic standpoint)

 

[Travis]

They are bad or good depending on what you compare them to. If comparing to any modern sport bike, they suck. If comparing to drum front, they are great!

 

[gentlemanjim]

Travis it be so very true.