Brake lever 'pulling away'?

[stp_1101]

I'll start by admitting that I'm going to do a bad job describing this, so please bear with me. I bought my 2009 C14 ABS just a few days ago. For the most part, everything's been great. However, today was the first time I tried moderate/heavy braking at highway speeds. To my surprise, after a second or so of braking, the brake lever (front, of course), started moving away from the bar (while I was holding constant pressure). Braking force also seemed to stay constant. This does not happen at slower speeds (less than 50 mph or so). It definitely seems to be related to heat in some way. The faster I'm going when I brake, the faster the lever moves back. Same thing if I brake harder. It feels like something in the brake system expands due to heat, but much more than could ever be considered normal. I did get some maintenance records with the bike, a shop installed new front pads about a year ago, along with new fluid. As much as I hate how loud the pads are, the performance is great (EBC HH pads). If anybody has experienced this before, I'd love to hear about it.

Thanks.

[Conrad]

Only one thing can be causing this.

You have air in the brake lines and as the fluid heats up the air bubble expands and causes what you're describing.

Are the brakes spongy at all?

[VirginiaJim]

Wondering if it's something with the ABS system?  Heavy braking should initiate that, although when it happened to me (several times) I don't remember the brake lever doing something like described above.

[just gone]

Silly question, but you are a C14 newbie right: You are very sure it's a 2009 model?..cause it sounds a lot like the strange feel that some get with the co-active braking of 2nd gen bikes, where the front lever doesn't move out but it gets an instantly much firmer feel to it when you press harder on the rear brake. 
Just a thought, no judgement about being a newbie was intended, we were all there at one time or another. I remember that when I first got mine, the first day I kept turning off the traction control thinking that I was turning it on. Later that day reading the manual while on the throne I realized my error. DOH!

Unrelated to the brakes, but an important newbie recommendation is to completely familiarize yourself both in knowledge and practice of using both the active and passive features of KIPASS.

[stp_1101]

I'll try to answer all the questions I've seen here.

Conrad, I suppose there could be air in the system, but the brakes are not spongy at all. It takes very little travel to generate a lot of braking force.

VirginiaJim, I wondered if it's ABS as well, I have no experience with motorcycle ABS. In every car I've used ABS in, there is significant shaking and general harshness when it activates. This is a very smooth effect.

fartymarty, not a silly question at all. I'm about as sure as I can be. The VIN on the frame matches the title, which says it's an 09, and entering the VIN into the insurance company's website brought up an 09.

I got to try it out again today, and I'm getting less sure of myself. It takes so little effort to slow it down, that I think I'm not necessarily holding constant lever pressure, as much as relatively constant braking force. It seems reasonable that performance oriented pads such as these might be a bit more effective when hot, so the increase in CoF is making me let up on the lever to achieve the same amount of braking? I'm really not sure anymore. I'm starting to think this might be general new bike stuff. Last time I got a new bike was in 2013.

[Freddy]

2010 models with linked brakes = K-ACT & K-TRAC were released in 2009.  Does it have those buttons on the grips?

[zrx mitch]

I'll try to answer all the questions I've seen here.

Conrad, I suppose there could be air in the system, but the brakes are not spongy at all. It takes very little travel to generate a lot of braking force.

VirginiaJim, I wondered if it's ABS as well, I have no experience with motorcycle ABS. In every car I've used ABS in, there is significant shaking and general harshness when it activates. This is a very smooth effect.

fartymarty, not a silly question at all. I'm about as sure as I can be. The VIN on the frame matches the title, which says it's an 09, and entering the VIN into the insurance company's website brought up an 09.

I got to try it out again today, and I'm getting less sure of myself. It takes so little effort to slow it down, that I think I'm not necessarily holding constant lever pressure, as much as relatively constant braking force. It seems reasonable that performance oriented pads such as these might be a bit more effective when hot, so the increase in CoF is making me let up on the lever to achieve the same amount of braking? I'm really not sure anymore. I'm starting to think this might be general new bike stuff. Last time I got a new bike was in 2013.

Are you using both brakes or only the front brake?

[maxtog]

VirginiaJim, I wondered if it's ABS as well, I have no experience with motorcycle ABS. In every car I've used ABS in, there is significant shaking and general harshness when it activates. This is a very smooth effect.

I can't speak to the gen 1 (2008/2009) C14's ABS, because it is different than the gen 2.  But on the Gen2, the ABS is like a quick buzz.  It isn't harsh and I don't recall the brake lever moving in or out or pulsing, other than the buzz feel.

As for gen1 vs. gen2, attached is a photo of the controls of a gen2 with ABS.  But determining gen 1 vs. gen 2 is easy because there are tons of changes (easily seen from a distance with the different fairings).  For example, if your dial/indicator backlighting is red (not white), it is a gen 1.

[gPink]

A pulsing lever could indicate a warped rotor.

[Freddy]

A pulsing lever could indicate a warped rotor.

True, but a warped rotor is felt more in the front suspension/bar/seat-of pants than the lever in my experience.

[jwh20]

The first thing I'd try is to completely flush and bleed the brakes, front and back.

Who knows how old the fluid is and what contaminants have built up over time?

Air is pretty commonly felt as "spongy" brakes but water absorbed by the fluid, which happens easily since DOT4 is hygroscopic (i.e. readily absorbs water from the surrounding air) and "water logged" brake fluid does NOT behave in a predictable manner.

[Jethrobolas]

I can't speak to the gen 1 (2008/2009) C14's ABS, because it is different than the gen 2.  But on the Gen2, the ABS is like a quick buzz.  It isn't harsh and I don't recall the brake lever moving in or out or pulsing, other than the buzz feel.

As for gen1 vs. gen2, attached is a photo of the controls of a gen2 with ABS.  But determining gen 1 vs. gen 2 is easy because there are tons of changes (easily seen from a distance with the different fairings).  For example, if your dial/indicator backlighting is red (not white), it is a gen 1.

I have definitely noticed my lever push back against my squeeze when abs activates.