wildbill Posted September 22, 2003 Share Posted September 22, 2003 Lately I've noticed a slow-speed handling quirk on my 02 Le Mans, like the bike wants to stand back up to the high side in a slow turn. Checked air pressure etc, then felt the rear rotor and it was scorching hot - sound like a warped disk to you? I do get a slight groaning when the bike is rolled backwards. If you think it's warped, is there any problem riding the bike prior to replacing the rotor, or bring it right in? Supposed to go to VT this weekend and was looking forward to a nice fast jaunt on the Le Mans... thanks all, great info here... Link to comment Share on other sites More sharing options...
al_roethlisberger Posted September 22, 2003 Share Posted September 22, 2003 I'll be curious to see the outcome of this. I too have a slightly warped rear rotor, and my dealer *had* been getting a new disc for me. But apparently Aprilia audited the "warped" rear rotors they had gotten back for warantee, and apparently only a small percentage(especially front rotors) ...something like 3 out of 100, were actually run out of spec. That said, Aprilia is apparently requiring you to actually bring the bike in to be inspected, and the dealer has to measure run-out of the disc before MG will warantee replace it. Mine groans in reverse, and even forwards a bit too It's not scorching hot after a ride, but the disc is warm.... warmer then the fronts. I wonder if just replacing it with a better disc like the "wave" discs would be a better long-term fix. al Link to comment Share on other sites More sharing options...
docc Posted September 23, 2003 Share Posted September 23, 2003 These rear brakes do seem problematic. First, they are hung under the swingarm in the worst of the weather. Very likely the outer 'flat' o-ring goops in its groove hindering piston retraction. A regular cleaning is in order. Second, (this is noted in another thread) the hanging lever exerts constant pressure up on the master cylinder. The Sport1100's don't seem to do this, but why? Finally, the master cylinder is mounted above the exhaust and may be heat sinking causing fluid expansion and applying braking force after the bike is heated up. This was noted by one of the magazines on an Aprilia Tuono with similar brake mounting. Time to design a heat shield? Link to comment Share on other sites More sharing options...
Guest PAULSMART Posted September 23, 2003 Share Posted September 23, 2003 Good theory Docc - I suffer the rear brake disk groans when pushing the bike around - I could'nt understand why as I very rarely even bother using the back brake Another mystery solved! Paul Link to comment Share on other sites More sharing options...
Baldini Posted September 23, 2003 Share Posted September 23, 2003 Rear brake was binding as described by Al. I adjusted the rear master cylinder actuating rod for max freeplay and fitted an elastic between the brake pedal & frame, to act as a return spring for the pedal. The binding stopped... ...for now... 1500 miles ago...it may be fixed... There's old threads on the site about this. Are the rear wheel bearings OK? - check esp. brake side. KB, Mid Wales Link to comment Share on other sites More sharing options...
wildbill Posted September 23, 2003 Author Share Posted September 23, 2003 Thanks guys, but do you feel the bike is OK to ride like that (I'll be doing 500+ miles this weekend, and if necessary could ride my bmw), and do you think this is the cause of what seem to be low-speed handling woes? Link to comment Share on other sites More sharing options...
Baldini Posted September 23, 2003 Share Posted September 23, 2003 Wildbill, Check out the old threads on this. Things can get very hot back there... KB, Mid Wales Link to comment Share on other sites More sharing options...
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