12-04-2019, 08:39 AM
(12-04-2019, 08:19 AM)max_imp Wrote: MP, assumptions are fine as long as you don't over-rate them, testing various things will point you in the right direction.
From what i read in your explanation there is one friction point on ( one ) of the disks, that does not mean the disk is bent, to test this you can hold a torch behind the brake pad, maybe open the pads up a bit so you can "see the light".
By watching the reflection in the gap and rotating the wheel you are likely to see a change in one place, if the opposite happens on the other side of the disk it is indeed warped and you may have a re-course on the tyre installer.
2nd thought; prise the pads away from the disk, put a sheet of paper in the gap and use the brake lever to close the gap so you can feel the sheet start to lose movement ( like with a feeler gauge ) then repeat the placing at all four pads and see which ones providing the pulsing, you may need some assistance here.
Another simple trick is Kiowa eagle's suggestion, put the old pads in and see if anything changes, here's why;
On my cb900 ( similar system ) i had a buildup of brake pad something, same effect as you describe, pulsing in one place of the wheel, i think this happened when i put the bike away after a wet ride, a little corrosion happened under the pads and because of the change in abrasiveness it picked up some material, i lived with it for some time until the pads needed changing and the problem went away for 90% and improved still more over time, that is all the explanation i can give you and maybe another good suggestion is coming up, no rush, take your time and find out what really happened.
Thanks, this is the kind of stuff that I need. Buying an expensive single-use tool just to get a "yes or no" answer on the condition of the rotors just seemed like a bad idea destined to put me more in the hole. I've already given the rotors a good scrub with brake cleaner, but i haven't used Acetone. I didn't know that was a good option. I actually thought that might have been the problem, just as you describe, because when i tried that i did imagine that it had improved a bit and the oscillation was less noticable, but not totally gone. the next day, however, i realized it was just my imagination and it was operating in the same way. Here's a question though: if I can't see the deposits on the surface, how will I know when i've scrubbed enough?
It was also suggested above that i disassmble everything and put it all back together to ensure that it went together the the way it was in the manual. I've done that before coming here to post, so if i'm making a mistake in that area, i couldn't tell you what it is.
I'll give the light and paper sheet ideas a try. those are free, and the light idea seems like it would provide a pretty definitive answer on the subject of the discs.
(12-04-2019, 08:39 AM)Lord Popgun_imp Wrote: To answer another question asked, a member posted that TRW MST278 is a direct replacement for CB1100 front rotors. I don’t know what they cost.
Thanks for that. I'll keep it on file. Would it be safer to buy both discs in the event that I do in fact have a bent disc, or is there no issue with leaving the unmolested original still in place?