warped rotor?

[elwaxoro]

Front brake use causes a regular bouncing motion- like it's gripping then letting go: warped rotor?

I took the bike in for tires last week, when I got it back, it didn't seem to be doing it anymore. Last night it was not noticeable, this morning it was so bad I didn't want to use it. Temperature seems to be a factor- last night it was 80+ and this morning it was ~45. Is that still consistent with the warped rotor theory?

Apologies for the newbie questions- this is my first bike, so I'm pretty much stabbing around in the dark here.

[jimfj]

I have the same problem on my Gs850. It started after I took the calipers off and cleaned everything up. One of my front calipers was sticking--meaning it would not move back and forth. I have no answer for you other than you may want to bleed the brakes. After doing all this to mine and its initial bleeding I still have some air trapped in the lines and need to get it out.

There will be someone with more expirience than I that will give us both an answer.

Jim

[Nessism]

If the rotor is warped, or has thickness variation, you will get brake pulsation all the time – not just when it’s cold/hot.

If the piston is sticking in the caliper at cold/hot temperatures, park the bike immediately. You are risking your life.

One other possibility comes to mind; the caliper is binding and not floating side to side like it is supposed to.

Brakes are pretty easy to work with. Remove the caliper piston and replace the seals. Grease the sliding pins and such. Replace the old rubber line. If the rotor is worn/damaged, replace it. Your service manual should have a servicing procedure.

Good luck.

[Matchless]

I seem to recall BassCliff refering to an issue that if you had recently replaced the disks with new ones and they were not properly 'burned' in this happens. I have seen it happen to a car. As the disks heat up when you use the brakes in traffic the sort of pulsing starts and gets worse and is apparently due to some transfer between the disks and the pads and the difference in expansion of the disks as they heat up due to this not done properly with some good high speed hard stops after installation.
Hopefully an expert on this will confirm this.

Edit here a link: Seems like I should read it as well:http://www.pagidusa.com/bedding_in_procedure.htm