+- The CB1100 Community Forum (https://cb1100forum.net/forum)
+-- Forum: Honda CB1100 Discussions (https://cb1100forum.net/forum/forumdisplay.php?fid=5)
+--- Forum: Mechanical & Technical (https://cb1100forum.net/forum/forumdisplay.php?fid=7)
+--- Thread: High Speed Front Brake Pulsation (/showthread.php?tid=5555)
Pages:
1
2
High Speed Front Brake Pulsation - AzBob_imp - 10-02-2015
Before I get a chance to tear the front brake apart, was wondering if anyone had any ideas:
Noticed yesterday coming home the front brake pulsates at speeds > 50mph under moderate to heavy braking. Bike has only 6k miles on it. I was thinking that one of the rotors might be slightly warped, but I don't see how. I plan on taking a look at both rotors and pads when I get a chance this weekend.
RE: High Speed Front Brake Pulsation - the Ferret - 10-02-2015
Are you sure its the brakes? How is the front tire?
RE: High Speed Front Brake Pulsation - Motogeezer1949_imp - 10-02-2015
I had a bad set of rotors. Waranteed. They are kind of thin and get hot easily, especially in the mountains. I use both brakes a lot now rather than mostly the front to try to keep them cooler.
RE: High Speed Front Brake Pulsation - grover_imp - 10-03-2015
(10-02-2015, 09:32 AM)Motogeezer1949_imp Wrote: I had a bad set of rotors. Waranteed. They are kind of thin and get hot easily, especially in the mountains. I use both brakes a lot now rather than mostly the front to try to keep them cooler.
^this. That sounds like warped brake rotors
RE: High Speed Front Brake Pulsation - Rocky_imp - 10-03-2015
I had this pulsating problem (very rapid grab release, grab release) with the front brake on my Bonneville last year during braking. Braking from a high speed was machinegun like and very annoying.
I changed the rotor and it was gone.
Very strange for it to happen on a low mileage machine that has never been abused, but it did.
No such problem with the CB.
RE: High Speed Front Brake Pulsation - dave - 10-04-2015
I've replaced two front brake rotors on my VFR800 over the past ten years that suddenly, and for no reason warped. My bike exhibited the same symptoms you describe. Out of curiosity, was your front tire replaced recently? The mechanic could have damaged the rotor when replacing the tire.
RE: High Speed Front Brake Pulsation - Rocky_imp - 10-04-2015
(10-04-2015, 05:09 AM)Dave_imp Wrote: I've replaced two front brake rotors on my VFR800 over the past ten years that suddenly, and for no reason warped. My bike exhibited the same symptoms you describe. Out of curiosity, was your front tire replaced recently? The mechanic could have damaged the rotor when replacing the tire.
No, the tire had not been changed.
While I was at it I took the opportunity to change the rotor with an EBC kit which included a new rotor and brake pads.
It much improved the braking so in a way I'm glad it happened.
RE: High Speed Front Brake Pulsation - immgunn_imp - 10-04-2015
They sell a dial indicator / vise grip tool for measuring rotor run-out. Maybe a parts store that lends tools has one. YouTube will show you how to use it. A micrometer is needed for thickness variation.
RE: High Speed Front Brake Pulsation - Tim_in_AZ_imp - 10-04-2015
Might just be brake pad deposits on the rotors.
RE: High Speed Front Brake Pulsation - Pterodactyl_imp - 10-04-2015
(10-04-2015, 12:37 PM)immgunn_imp Wrote: They sell a dial indicator / vise grip tool for measuring rotor run-out. Maybe a parts store that lends tools has one. YouTube will show you how to use it. A micrometer is needed for thickness variation.
A runout check is good advice. A basic check, to see if there is any runout, can be done by clamping a wire, or other object, in touch with the rotor and then rotating the wheel. Any significant runout can be then observed by eye. To measure that runout you will need a dial indicator. A reasonable quality dial indicator is not expensive. Runout limits are described in the service manual. I don't have my manual by my side but will post the runout limit if you need.
Cheers.
Minimum rotor thickness is 3mm. I measured mine last week.