Front Brakes ain't what they used to be

[misterprofessionality]

It was only after riding with another CB this past weekend that I realized my front brake responsiveness on the old CB just isn't what it used to be.  Its as of the engagement position on the lever is about 15-20% farther down than on a fresher bike. The brakes work.  They stop me just fine. There's no squeak.  The pads are relatively new with less than 4000 miles on them.  The fluid is fresh, and the performance didn't change for better or worse after it was bled. 

Any ideas what could be causing this? What can I do to get those snappy CB1100 brakes back?

 

[Cormanus]

Worn rotor?

 

[misterprofessionality]

Those are also relatively new actually. 4000 miles.

 

[Cormanus]

Not that, then.

 

[1973cb750]

i find greasing the pivot point on the lever makes a huge diff and the slide pins on the calipers i grease my clutch and brake pivot twice a year at least it really ninds up if you dont also the small rub point on the master

 

[misterprofessionality]

Yes, I do grease up the slide pins each time I change the pads, which with my mileage is pretty close to what you're describing. As far as the pivot point goes, it isn't really the smoothness that's in jeopardy. It's more like an engagement issue. It almost feels like the back pressure on the piston in in the master cylinder is reduced.

 

[peterbaron]

It was only after riding with another CB this past weekend that I realized my front brake responsiveness on the old CB just isn't what it used to be.  Its as of the engagement position on the lever is about 15-20% farther down than on a fresher bike. The brakes work.  They stop me just fine. There's no squeak.  The pads are relatively new with less than 4000 miles on them.  The fluid is fresh, and the performance didn't change for better or worse after it was bled. 

Any ideas what could be causing this? What can I do to get those snappy CB1100 brakes back?

Good pics of the rotor's surface/4 and the pads surface/4 are needed.
I assume that front brake lever is firm and hard when pressed?

 

[Whoops]

It was only after riding with another CB this past weekend that I realized my front brake responsiveness on the old CB just isn't what it used to be.  Its as of the engagement position on the lever is about 15-20% farther down than on a fresher bike. The brakes work.  They stop me just fine. There's no squeak.  The pads are relatively new with less than 4000 miles on them.  The fluid is fresh, and the performance didn't change for better or worse after it was bled. 

Any ideas what could be causing this? What can I do to get those snappy CB1100 brakes back?

You said fresh, but when did you last change the brake fluid? I know the manual says 2 years, but I feel like that's something that I prefer doing annually, especially with an ABS system with no test function to help cycle old fluid out of the pump.

 

[misterprofessionality]

I mentioned that. It was recently bled fully and the performance of the brakes did not change in any way before or after the bleed. Recently means 3 weeks ago at this stage.

 

[Whoops]

I mentioned that.  It was recently bled fully and the performance of the brakes did not change in any way before or after the bleed.  Recently means 3 weeks ago at this stage.

Righto. Could it be aging or degradation in a master cylinder seal is possibly reducing pressure at the calipers when you squeeze the lever? Maybe the master cylinder rebuild kit could yield results?

 

[misterprofessionality]

well...i admit i dont know anything about the longevity of master cylinder seals and such. The one that's in there was changed out about 4 years ago for a new seal, spring, and piston. How often are these things supposed to be changed out?

 

[Whoops]

well...i admit i dont know anything about the longevity of master cylinder seals and such.  The one that's in there was changed out about 4 years ago for a new seal, spring, and piston.  How often are these things supposed to be changed out?

I would put your expertise far above mine in that respect. I would also think 4 years wouldn’t be enough time for them to go bad, so clearly I’m just tossing stuff at the wall to see if anything sticks.