2014 DLX - rear ABS clunk

[kvdv_imp]

I think I might already know the answer, but I have to ask... is it normal to hear and feel a pretty noticeable "clunk" when pressing the rear brake pedal hard enough to engage ABS? We have a very steep driveway/entry to our underground parking at the condo, and one day it was a bit wet out when I pulled in a little hot and stomped a bit hard on the pedal so as to stop on the incline and watch the door close behind (as per condo security rules). In doing this, I felt the pedal "hitch" down a little and at the same time heard a bit of a clunk from the rear end, but the bike definitely stopped without either tire locking. I thought it very odd that an ABS system would exhibit something like this yet at the same time seemingly function normally...
I parked the bike, inspected everything from pads to fasteners, brake pedal, even the right foot peg, everything is in beautiful shape and tight as a drum. Out of curiosity I've tried to recreate the effect since and sure enough, when pressing the brake pedal hard enough so that it would surely lock up a non-ABS system, I get that odd rickety clunk as the bike quickly stops. Mind you, I would never try this experiment at anything over 10 or 15 mph. Again, I've inspected everything, fenders, chain tension... is it possible that what I'm hearing is normal? It can't be, right? Or is it?

[Pauley]

I have a 2013 with abs and I get the same effect so it must be normal.


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[dave]

My rear ABS acts similarly, and I think the way the rear ABS works on my bike is odd. I tested mine several times at speeds from 30 to 50 mph and the results are always the same. I think the noise (clunk) is caused by a combination of the brake pads releasing the rotor and allowing the wheel to rotate after momentarily locking, and the chain slapping as the wheel quickly begins to rotate again. The rear ABS on my bike certainly does not act like any ABS I have ever experienced while driving a car, and I have used ABS in a car many times while driving on icy, winter roads in upstate NY. The ABS in the cars I have driven functioned by pulsing the brake system pressure off and on at several hertz (you can feel it in on the pedal), but on my bike there is none of this high-frequency pulsing. It feels like the frequency that the rear ABS operates on my bike is much slower. I posted a thread on this topic several months ago and another member responded with information describing how the CB1100 ABS worked - so there is a better explanation out there if you're willing to look for it.

[kvdv_imp]

Gentlemen, thanks for the replies. Well, I'll be darned! I'd have sworn I was going to hear back that this was most concerning and that I'd better get it checked out professionally asap. I'm surprised that this is the just the way it works, but since that's the case, I guess I won't worry about it. I almost never brake hard enough to engage it anyway (unless I was trying to), so "case closed," I suppose!
Thanks again!

[Easynow]

Apologies for dredging an ancient thread - I wanted to add that I have the same on my 2014.

An audible 'clunk' when braking hard enough to lose traction in the rear. The bike stops quickly with no drama other than the clunk.

I don't see anything untoward at the caliper. I thought maybe it's the swingarm bearing or something.

But now I'm unconcerned because of the other replies. Brilliant.

[peterbaron]

All three of mine CBs have ABS, and the 2013 model had cABS, and I have never heard any noise, clunk, qout, knocking or anything like that from the rear wheel or ABS.

[Easynow]

All three of mine CBs have ABS, and the 2013 model had cABS, and I have never heard any noise, clunk, qout, knocking or anything like that from the rear wheel or ABS.

Damn you! 

[Cormanus]

Well, Easynow, there's a couple of possibilities there: there maybe no knocking or clunking or carrying on, or there may be heaps but peterbaron's hard of hearing.

[peterbaron]

Well, Easynow, there's a couple of possibilities there: there maybe no knocking or clunking or carrying on, or there may be heaps but peterbaron's hard of hearing.

Cormanus, I heard when you were typing....but it's true about my hearing.
In August, I will be testing my CB abs on an icy surface and lyk

[Cormanus]

Please be careful in August, peterbaron.