07 gsxr 600 Brake issue
Firstly the front master brake cylinder recall was 'taken care of' by a reputable local motorcycle shop.
This bike was purchased from a private seller this year, who had the front master recall done at said shop last year. Checked with the shop and they concurred, they replaced the master cylinder.
First day after 5 minutes of riding, the front brakes (left and right caliper) on their own begin applying pressure and slowed the bike to a stop mid corner with my wrist still trying to throttle. I pull over the best i can front brakes about fully locked, and the brake lever is stiff, completely not like it was moments before.
Called the seller and he walked me through how to release the brake pressure. (opening the bleeder valve nearest the master brake cylinder, squeezing the lever than re tighten the bleeder. Worked and it got me home.
Try riding the next day, same issue occurs. I bleed the brakes, and continue on riding the rest of the day brakes working as normal. I let the bike sit over night or possibly two and attempt to ride it again. i hear the brakes start to squeak, and the brakes start slowly applying pressure like it did before.
Did some research online, and attempt to change my brake fluid. went well, fluid was just as clear as the new stuff i'm replacing it with. bike sits over night, test it the next day and the same instance occurs.
Fast forward a few weeks, made an appointment at the same shop which is an hour away. Told them what I've done and that flushing it with my minimal tools didn't solve my problem. They flush the brake fluid with their tools, let the bike sit overnight and test it the next day. working fine. I show up a few days later to pick it up and we can hear the squeaking as he rolls it outside. They solved nothing. I asked if it could be some small piece of gunk lodging itself in a small hole in the master cylinder, and they said probably not it was replaced the year before.
Was not pleased and i drove it home. ( did a wheel to wheel inspection as well and they dropped the cost from $350 to $250) effing sweet deal
on the way out the mechanic suggested i try replacing the brake lines entirely, and if that doesn't work replace the calipers.
Well here i am today, i replaced the brake lines with steel lines with ones that are set up slightly different. Stock lines are rubber or whatnot, and the right line (longer line) runs down from the master cylinder and piggy backs with the left line at the right caliper. Than it travels around to the left caliper.
The new lines are steel and piggy back at the master cylinder, and run down to their respected calipers. I get them up to pressure and go for a test ride. Worked great, for 40 minutes.. The whole time i had been testing the brakes at multiple speeds, being ready for it to do it again. All seems good, get it up to 100mph and when i let off the throttle, the brakes are coming on harder than i've ever braked before at them speeds.
It has to be something wrong with the master brake cylinder right?
Something settles and clogs a small hole, and it acted crazy fast on my steel lines because they have no give when pressure occurs. When the lines were stock, they had give and took slightly longer and didn't brake nearly as quickly and hard.
And the switching of brake lines and new set up, doesn't that debunk the calipers being the issue theory?
they are both slowly seizing up in unison, i can feel equal heat on the discs when these instances occur.
I appreciate any of your thoughts on this, thank you Cheers