Brake puzzle with GS500

Discussion in 'Tech Area' started by RCB600, Jul 11, 2010.

  1. RCB600

    RCB600 RCB600

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    Saturday May 22nd in the first morning practice I felt my front brake fading after 2 laps. (could not make turn 1 and turn 3). Before the second practice I bled the brakes and checked oil level. (nothing unusual)
    After 2-3 laps in second practice I had same failing front brakes. My lever was also not properly locking in widest position so decided to drive home and pick up new lever and oil (DOT-4)
    Working on the bike I found out that my new ?unbranded? brake pads were completely worn after the few 8 morning practice laps (less than 1mm left)!!. Cleaned out the caliper and bought set of EBC HH pads at the track. Replaced the lever, installed new pads,flushed oil and was ready to go for afternoon races.
    First race (MWT) , after 3-4 laps bike slowed down (felt like loosing power) on main straight. Decided to run out the lap slowly and went to pits to check on ignition and fuel delivery. Found a bad plug connection and blamed it for the trouble.
    Second race (Vintage), after 3-4 laps bike slowed down again and to save engine I slowed down again, went to pits and removed carbs for complete check up. Verified and reconnected all ignition wires etc.

    Sunday May 23rd. First practice. Rode slow first 2 laps, than pushed in 3rd lap. Coming full throttle to turn 3. Hit my brakes and got instant front end lock-up.So I was airborne !
    I cannot remember anything from the crash as I was knocked out for a minute or two. Also do not remember transportation to hospital.
    Simon told me that the front end was solid locked up when they picked up my bike. Alex, George and Kevin took care for loading up my truck and bring all home as I was in Hospital for two days. Thank you guys.
    Injuries not too bad. Broken collar bone and some bruises. Helmet however is shot and leathers were cut in pieces too!
    Now the puzzle !!
    Apparently I had brake problems on Saturday morning (wearing out new set of pads in few laps) I must have head same brake problems in the afternoon with the new brake pads (explaining loosing speed on the straight)
    However I did not notice a front end brake dragging !
    See enclosed the pictures of the front disk and EBC HH brake pad. Disc turned blue and brake pad glue came loose from backing and dripped in disc holes as bike was laying down.

    Blamed it on bad lever (not releasing properly). However testing afterwards, few weeks ago, showed that it could not have been the reason.
    Maybe too much oil, NO, level was correct.
    Hanging caliper, NO all is moving freely and easy. (pins are all OK)

    Still have no clue what caused it to lock up. I am just happy it did not lock up on its own, coming in to turn 1, or going in 5 or exiting last corner !
    Installed new disc and new set of standard brake pads.
    Quitting racing, not so much of my innury, but mor the fact that I am running 2 companies and cannot afford being out too long. Maybe few track days only. (don't know yet) GS500 will go up for sale end of season and still need to finish up my SV650 project. (details in other story soon)
     

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  2. Dennis

    Dennis New Member

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    Is it possible the master cylinder has something intermittently plugging the little hole that the fluid is to pass through when returning after the lever is released?
     
  3. RCB600

    RCB600 RCB600

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    Hi Dennis, Could be possible. I removed the whole brake system, flushed it and re-installed. Nothing odd showed up. As at this moment its all working OK. Guess the race track will need to prove it. (At least no aggressive EBC HH are installed now)
     
  4. Simon

    Simon New Member

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    Replace your brake hose, see this all the time with cars.
     

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