Pulsing in the Rear Brake Pedal

[rndlmn4]

My T7 is the first motorcycle I've had with ABS. I also know that the T7 swingarm is designed to counter rear end squatting.  When I apply the rear brake in a normal way - not hard braking - I feel the pedal pulse lightly under my foot. This happens on dry, good traction, surfaces. There's no need for ABS to activate, and the indicator light on the dash does not come on. Being new to this feature, I'm wondering if the pulse I feel in the pedal is ABS - even under normal braking. Or, is an affect of the anti-squat swingarm design. For reference, the rotor is straight and the pads are good. Anyone else feel pulsing in the brake pedal.

[Mapbook]

If the rotor is true check the thickness it might have worn thin at one point.

[Dougie]

Yeah sounds like the rotor. How true is it? Dial gauge or eye? Is the chain slack correct and well lubed? Does the wheel feel different turning freely when on a stand/lift? Is the wheel fitted straight? ( really, and not just on the swing arm marks) These would give different resistances as the wheel and chain goes around noticed more under braking. Rotor for actual pulsing pedal though. Could just be a rough patch on the disc/ uneven wear as @Mapbook says. 

Edited May 20, 2023 by Dougie

[mpatch]

Either warped rotor or you have a spot on the rotor that’s slick. 
First thing I’d try is scrubbing the rotor with some sandpaper or a scuff pad and see if that fixes it. 

[rndlmn4]

Thanks for the suggestions; I do appreciate it and will check the rotor more closely.

 

Today, I did a longer ride with a lot of gravel and some nasty downhills (muddy and roached out by side-by-sides), giving me a chance to really utilize the Off-Road mode. I did not feel any pulsing when rear ABS was shut off. I'll take a close look at the wheel speed sensor ring to make sure all of the slots are in good shape. If I make any discoveries, I'll follow up here.

 

[Rich TT]

5 hours ago, rndlmn4 said:

Thanks for the suggestions; I do appreciate it and will check the rotor more closely.

 

Today, I did a longer ride with a lot of gravel and some nasty downhills (muddy and roached out by side-by-sides), giving me a chance to really utilize the Off-Road mode. I did not feel any pulsing when rear ABS was shut off. I'll take a close look at the wheel speed sensor ring to make sure all of the slots are in good shape. If I make any discoveries, I'll follow up here.

 

Hi. I think you've answered it yourself here.

 

It must have been the ABS coming on, as that's exactly what it feels like, and maybe you were pressing the rear brake pedal harder than you thought you were perhaps?

 

I had to put mine in off road mode when I was riding the passes of the Pyrenees downhill as the rear ABS would come on all the time and was annoying. I was riding quite hard. I always switch it off when I'm off road.

 

For reference if the ABS ring is bent, it will show the ABS light on the dash.

 

Cheers

Rich

[rndlmn4]

19 hours ago, Rich TT said:

Hi. I think you've answered it yourself here.

 

It must have been the ABS coming on, as that's exactly what it feels like, and maybe you were pressing the rear brake pedal harder than you thought you were perhaps?

 

I had to put mine in off road mode when I was riding the passes of the Pyrenees downhill as the rear ABS would come on all the time and was annoying. I was riding quite hard. I always switch it off when I'm off road.

 

For reference if the ABS ring is bent, it will show the ABS light on the dash.

 

Cheers

Rich

 

Rich,

 

I haven't noticed the ABS light coming on while applying the brakes, but maybe the brake pedal force is enough to cause some pulsing, but not enough to trigger the indicator light. I know that doesn't make sense because it's electronically controlled. A condition that would cause the control unit to modulate the brake line pressure, should also cause the indicator light to come on. It's not as if brake pedal force triggers the indicator light.

 

I do notice that the ABS light comes on when starting the bike, and it remains on for a moment before turning off, before even moving the bike... hence no ABS ring input. I haven't timed how long it stays lit.  I need to ride on some grass with ABS on, and try braking hard to see if the light comes on. Too bad you can't go into dealer mode (or some sort of analytics app) and see when different electronically-monitored/controlled events have occurred.  

 

Scott

[Uncle M]

@rndlmn4 I've never had the ABS light come on while braking. The owner's manual says the ABS warning light will only come on (after the initial start-up) if there's an ABS system malfunction.

[Firebolter]

The light also comes on when you go to OffRoad or ABS off and stays on until you turn off the ignition. It is normal to feel the rear pulse some under load as the bike slows, more so if you get on the rear hard. The ABS system on this bike is crap. I turn my off every time I ride the bike. I rode mine to work today and got on the rear a little hard at speed on purpose, and sure enough it will pulse some as you slow down and push harder on the pedal. At the next light I turned it off and no pulsing with the same experiment when I repeated it.

 

I have Cory's new pedal and it helps alot, but the ABS used is just crap IMO. You should check your rotor, but you'll probably find it is not warped and you don't have any bad spots-Still using stock brake pads? They suck too!

Edited May 22, 2023 by Firebolter

[rndlmn4]

On 5/22/2023 at 10:58 AM, Firebolter said:

I have Cory's new pedal and it helps alot, but the ABS used is just crap IMO. You should check your rotor, but you'll probably find it is not warped and you don't have any bad spots-Still using stock brake pads? They suck too!

 

Cory's pedal? Is that the Camel "Fix", or something different?  I always ran EBC HH pads on my V-Strom and thought they worked well. I had braided SS brake lines on it too. Some of the T7 mod lists I've seen tend to show Gafer pads. I think that's what my KTM 300 XCW had on it, and it had great brakes.