drew95gt Posted August 6, 2012 Report Share Posted August 6, 2012 Picked up a gently used 2007 Ninja 650R last week (4k miles on it) to satisfy my sportbike/commuter itch and I have a quick question. The thing runs awesome, but the front brake seems to be "surging" or like grabbing and releasing...like what you would imagine if you squeezed and released the brake lever over and over again. There is no shake or shimmy with high speed braking, this is more of a lower speed issue. Any ideas of what it could be? The pads look great and the rotors show no signs of neglect and no squealing or other problems. Thanks for any ideas of where to start tracking down this issue. Quote Link to comment Share on other sites More sharing options...
Helmutt Posted August 7, 2012 Report Share Posted August 7, 2012 Warped rotors, check the runout Quote Link to comment Share on other sites More sharing options...
J_Copeland Posted August 7, 2012 Report Share Posted August 7, 2012 ^^^^This !!! Quote Link to comment Share on other sites More sharing options...
chevysoldier Posted August 7, 2012 Report Share Posted August 7, 2012 Yes, Warped rotors. Quote Link to comment Share on other sites More sharing options...
drew95gt Posted August 7, 2012 Author Report Share Posted August 7, 2012 Will check...that seems kinda odd for such a low mile bike to have warped rotors though doesn't it? I thought it may have had something to do with the fact it sat for basically 1 and a half years. Quote Link to comment Share on other sites More sharing options...
J_Copeland Posted August 7, 2012 Report Share Posted August 7, 2012 I had a bike with 1,700 miles with warped rotors. 1 Quote Link to comment Share on other sites More sharing options...
drew95gt Posted August 7, 2012 Author Report Share Posted August 7, 2012 Cool, I will change them out then..thanks guys. Quote Link to comment Share on other sites More sharing options...
Helmutt Posted August 7, 2012 Report Share Posted August 7, 2012 Will check...that seems kinda odd for such a low mile bike to have warped rotors though doesn't it? I thought it may have had something to do with the fact it sat for basically 1 and a half years.Never know, sometimes a little abuse goes a long way. Jack up the front wheel or the whole bike to get some sort of pointer or indicator up against the side of a rotor. Spin the wheel and you'll know right away which one is bad or possibly both. You may get lucky and find some rotor bolts have backed out causing the imbalance, but I'm doubting thats the case. Free-floating rotors or are these one piece? Sorry, not familiar with 650R's Quote Link to comment Share on other sites More sharing options...
drew95gt Posted August 7, 2012 Author Report Share Posted August 7, 2012 (edited) Free floating...and the thing that got me was there was no high speed shimmy like you would expect from a warped rotor. It is more of a pogo effect (even the fork compresses and rebounds slightly) when applying the brake. It is weird...no shake to the bars or anything just a bouncing like slamming the brakes on and off. I will check the rotor bolts too, good idea. It is funny, kinda makes me look like a noob when stopping like I am jamming the brakes then letting off. Edited August 7, 2012 by drew95gt Quote Link to comment Share on other sites More sharing options...
magley64 Posted August 7, 2012 Report Share Posted August 7, 2012 the master bleeback port slightly clogged?The brakes didn't like to release on that cb900c, and the master bleedback port was completely clogged. 1 Quote Link to comment Share on other sites More sharing options...
Helmutt Posted August 7, 2012 Report Share Posted August 7, 2012 Slightly warped rotors at speed "may" feel like more of a vibration, or tick, or barely noticeable at all until its moving slow enough allowing you to feel more of the drag against the pad. I dont have a lot of experience with warped rotors but do listen to smart folk on occasions, so I falsly appear like I be more smarter than I is:D 1 Quote Link to comment Share on other sites More sharing options...
drew95gt Posted August 7, 2012 Author Report Share Posted August 7, 2012 Thanks again and +rep to all you guys for the help. Quote Link to comment Share on other sites More sharing options...
oldschoolsdime92 Posted August 7, 2012 Report Share Posted August 7, 2012 Triumph used to do a similar thing, brake dust would build up on the pistons, and I had to get in there and clean the pistons with brake parts cleaner. 1 Quote Link to comment Share on other sites More sharing options...
drew95gt Posted August 7, 2012 Author Report Share Posted August 7, 2012 I'm going to try and clean everything first, especially since the bike sat for a while. Perhaps the little buttons are seized on the floating rotors as well, looks like I will be spending my next day off in the garage...lol. I'm going to try everything besides full replacement first, OEM rotors aren't exactly cheap, but if it needs them..it needs them. Quote Link to comment Share on other sites More sharing options...
drew95gt Posted August 8, 2012 Author Report Share Posted August 8, 2012 Cleaned the buttons on the rotors so they spin freely now, several were seized up probably due to sitting and not being ridden in a long time. I also scuffed the surface of the rotors which helped as well. Took it for a test spin and it is much improved...will still probably throw some new pads on after the summer when I change the fluids. Thanks for the help and ideas. Quote Link to comment Share on other sites More sharing options...
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