The return of the Oscillation

[max]

On my hornet the oscillation was slowly changing, it seemed that the "sticky patch" was getting bigger ( longer ) and less apparent, so it seemed to fix itself over time.

You could feel it when applying and maintaining the brake lightly whilst pushing the bike forward through the cycle.

What fixed it in the end ( to my surprise ) was a change of pads

So something simple to try is to replace the pads or swap them around and write down what went where so it can be traced back later, just an idea, the shop sounds good too.

Something else that happened to me was the forward cup of the master cylinder was oversize in the master cylinder and was not clearing the small breathing hole in the master cylinder ( dragging ), took me a while to find that but a new cup fixed that, probably not your problem but worth knowing.

Thanks for bringing up the subject MP.

[jtopiso_imp]

Check if the caliper pistons are retracting properly. Or check if the front calipesr are heating up after a ride, even if you brake with the rear.

I had the same problem on an old car: it warped a set of discs, replaced, and did the same to the next set. It ended up being too much fluid on the reservoir, so when the system was heated the liquid expansion was enough to apply some braking all the time, leading to overheating the discs and warping.

Or just check fluid level and make sure it's not over the "max" mark.

[misterprofessionality]

Small update: the fluid level is normal, the lever doesn't seem to have excess play against the piston, but I did try an experiment by riding home from work today without using the front brake at all. When I parked I took my glove off and felt each disc, one was cool, one was hot. Not crazy hot but definitely hot. Of course, this is the one that's on the same side as the one brake pad that's more worn than all the others.

Conclusion: yea one of those calipers is dragging slightly at all times.

[GoldOxide_imp]

... excellent. Glad you were able to safely arrive home Mr. P. with just the rear brake.

[misterprofessionality]

Its not so hard.

[1973cb750]

i weigh 235 and i run about 6 more psi in my front and the cupping has almost been eliminated i think a cupping tire causes your issues

[Tev62]

I take it the front wheelbearing is in good order and that there isn't a little play giving rise to a little one sided lean on the wheel and hence the rotor?