claudea Posted February 26, 2009 Share Posted February 26, 2009 1992 FZR 600 - Genesis Pulsing rear brake. Disc has been checked and it’s not warped. With the bike off the ground, spinning the wheel with the pads in place is enough to notice them contacting just one spot. This is enough to cause the rear wheel to lock under braking. The bike has only done about 30k and this problem appeared suddenly. I have removed the disk, checked the 6 mounting points for the disk and they’re all clean, Cleaned all the threads with a tap. After cleaning all the bolts I have used Loctite (blue) on the bolts each time. Steps taken so far with the bike on a stand and the pads removed: . With a dial gauge on the disk there is a high spot/ run-out of .012mm . Rotated disk and the spot is always on the same position on the wheel. . Tried another disk on my wheel and the high-spot / run-out was 0.006, same position on the wheel. . Tried another wheel - and my disk and same result, - and with another disk same result Axel is straight. All wheel bearings replaced, but no change. Have also checked it without fully tightening the axel but there is not change. Have run out of ideas on what could be wrong and how to correct the problem. Not very keen on sanding down the disk mounting points to remove the high spot. Any thoughts or suggestions. Link to comment Share on other sites More sharing options...
JimR Posted February 26, 2009 Share Posted February 26, 2009 1992 FZR 600 - Genesis Pulsing rear brake. Disc has been checked and it’s not warped. With the bike off the ground, spinning the wheel with the pads in place is enough to notice them contacting just one spot. This is enough to cause the rear wheel to lock under braking. The bike has only done about 30k and this problem appeared suddenly. I have removed the disk, checked the 6 mounting points for the disk and they’re all clean, Cleaned all the threads with a tap. After cleaning all the bolts I have used Loctite (blue) on the bolts each time. Steps taken so far with the bike on a stand and the pads removed: . With a dial gauge on the disk there is a high spot/ run-out of .012mm . Rotated disk and the spot is always on the same position on the wheel. . Tried another disk on my wheel and the high-spot / run-out was 0.006, same position on the wheel. . Tried another wheel - and my disk and same result, - and with another disk same result Axel is straight. All wheel bearings replaced, but no change. Have also checked it without fully tightening the axel but there is not change. Have run out of ideas on what could be wrong and how to correct the problem. Not very keen on sanding down the disk mounting points to remove the high spot. Any thoughts or suggestions. Hi, have you checked the caliper ? if you have the other bits checked .... it leaves 2 options ... the caliper (likley) or the swing arm. If the caliper has seized and you didnt notice this may twist under the heat of the binding brake (Yamaha calipers are not the best) and hence you have a problem that you cannot find because it is not supposed to go apepoo. So if you have a caliper & some new pads it might well be worth trying them too. Regards Jim Link to comment Share on other sites More sharing options...
claudea Posted March 2, 2009 Author Share Posted March 2, 2009 Hi, have you checked the caliper ? if you have the other bits checked .... it leaves 2 options ... the caliper (likley) or the swing arm. If the caliper has seized and you didnt notice this may twist under the heat of the binding brake (Yamaha calipers are not the best) and hence you have a problem that you cannot find because it is not supposed to go apepoo. So if you have a caliper & some new pads it might well be worth trying them too. Regards Jim Jim, The checks were completed with the bike on a stand and without the pads. So there is no load on the wheel and the disc is free, eliminating the caliper or pads as the cause or contitibutor. Not sure how to check if the swing arm is causing this. - What I have tried is disc on the wheel and mounted on the bike, . I have tighten the axle bolt as per normal, . Then backed it off so that is just keeping the swingarm in touch withn the hub but the problem is stilll there. How should I check the swing arm? I'll look at getting an overhall kit for the brakes once I get this issue sorted. Thanks Link to comment Share on other sites More sharing options...
JimR Posted March 8, 2009 Share Posted March 8, 2009 Jim, The checks were completed with the bike on a stand and without the pads. So there is no load on the wheel and the disc is free, eliminating the caliper or pads as the cause or contitibutor. Not sure how to check if the swing arm is causing this. - What I have tried is disc on the wheel and mounted on the bike, . I have tighten the axle bolt as per normal, . Then backed it off so that is just keeping the swingarm in touch withn the hub but the problem is stilll there. How should I check the swing arm? I'll look at getting an overhall kit for the brakes once I get this issue sorted. Thanks Hi there, here is a page from the Yamaha workshop manual as you can see the run out is .5mm so the run out on yours discs shouldnt be an issue with the problem you have, so perhaps you need to look else where .. I guess you have changed the caliper mounting bracket as this could be warped. To check the swing arm for alingnment ensure that the wheel is at the same ref point (for chain adjustment) on both sides of the arm then visually check the wheels are in line, if not you may have a slight bend in the arm itself Regards Jim Link to comment Share on other sites More sharing options...
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