Rear brake rotor "hot" spots

[columbusgary]

IMG_5536[1].jpgIMG_5537[1].jpg
Just noticed the "hot" spots on my rear brake rotors the other day. They are visible all the way around the rotor in the same pattern. I bought the bike new last spring. Put 700 miles on it last year and took it to the dealer for the 600 mile check up/oil change and then garaged it for the winter. I've had it out a few times this spring (150 miles). The back brakes WORK fine. I'm wondering if anyone has seen or can explain the hot spots on the rotors. I can't be certain they were not there prior to the service, but I'm suspicious... Any ideas?

[1Cruiser]

I've never seen one like that. Take it to the dealer and keep us updated.

[russellohioboy]

I had 44,000 miles on my raider and it never looked like that either. Does the back brake feel like it is dragging? I had a problem like that one time and I had to push the brake hard a couple times and then it freed up. If i let off the gas while riding it would slow me down when it was dragging.

[Beethoven]

Interesting. I removed the "accent" piece (the finny thing) and polished my rotors so they looked like chrome. After a while I noticed a heat discoloration that looked like rust, but was in the surface of the metal. I just did my rear tire, and put the cooling piece back on. I also did the rear pads (28,000) and checked the piston and it was fine (no binding). I am wonderig if I might be touching the brake lever a tiny bit when I ride. I am going to adjust the linkage so I have to move the lever more before the brake engages. I never had a problem with "brake fading" or any sign that things were on all the time, but I did see heat discoloration.

[almost_there]

That doesn't look right at all. Is it possible you are resting on the brake while riding? Maybe you're not riding enough and the brake seized a bit? Maybe with all your enthusiasm with the new bike, you hauled ass all over town and were braking hard?

I would guess this happened for a short period and resolved itself; however, it happened long enough to tarnish the rotor. If this dragging was a continuous issue it would look much much worse.

I'd replace the rotor and inspect the pads. Once the metal is overheated its structure is changed and there may be micro-cracks. Good luck!

[CharlieA]

It could have got contaminated at some point. Solvent, oil, gas, almost anything could have been splashed on the rotor then when you rode it and used the brakes it caused the discoloration. However I agree with the prior post, at any point no matter the cause it would not be a bad Idea to replace the rotor & pads because of the effect the hot spots have on the metal. If you happen to know a good machine shop you may try to have the rotor resurfaced. I don't think I would take more than .005-.010 in. per side unless yamaha gives a spec. for min. thickness.
Charlie

[coldfinger]

Seems like they are about equal distance between, no?

Maybe retorque the bolts that hold the rotor.

Spin the rear wheel and see if the rotor is warped.

If the brake pads have been replaced, maybe the pistons were dirty when they were compressed and now there is a little grit holding the pistons or keeping the pistons from releasing after you brake. I went thru a set of pads real quick on my Concours because I didnt clean the exposed piston surface before I compressed it to fit the new pads and the pads were dragging.