I think you should adjust your brake pedal free play.
I know this is an old posting, but hate to start a new one. I've recently had this happen twice. Had Accutronix controls put on about 3000 miles (6 months) ago by Honda. All was well and then about 200 miles ago the back brake started to lock up. By the time I stopped it was totally locked. Called a tow truck. By the time it came the breaks were fine. So rode it home and for another couple hundred miles. Then the same thing happened. I pulled off and hit the pedal a couple times with my hand. Everything worked fine again.
Should I take it to Honda for an adjustment or is it something easy that I can adjust? Hate to go to Honda because I'm sure they would want me to leave it and pick it up which means I need to find rides and lose the bike for a day or two.
Thanks if anyone is still reading this thread.
John
Your brake pedal free play needs to be adjusted correctly for your brakes to function correctly. If you have air in the system, the brake pedal will travel long way before the brake works, if it works at all. Therefore air in the system will not cause the brake to lock up unexpectedly. Too much free play can cause the brakes to not work at all. Too little free play can cause your brakes to drag. Dragging brakes creates heat and may expand the brake fluid causing even more dragging. This excessive dragging can discolor or even warp the brake rotor. This can cause the brake to lock until the fluid cools. This is true with ALL brake systems, not just Accutronix.
1) Pull the rubber accordion boot back so you can see the brake push rod, the brake piston, and the brake piston snap ring.
2) Push the pedal down while watching the push rod move the piston into the master cylinder and away from the snap ring.
3) Slowly lift the up the brake pedal and watch the brake piston seat against the brake piston snap ring.
4) After the brake piston is seated against the brake piston snap ring, keep lifting on the brake pedal. Watch the push rod separate away from the seated brake piston, this separation is the brake free play. Measure (by eye) the separation distance. If the brake push rod does not keep moving after the piston seats against the snap ring, you have NO free play.
5) The distance between the push rod & the seated piston should be 1/8” to ¼”. To increase the free play, loosen push rod lock nut with a ½” wrench. Then screw the push rod into the heim joint shortening the overall length & then tighten the lock nut.
6) Verify the correct free play measurement & correctly install the rubber accordion boot.
NOTE:
1) The brake fluid level should be 3/16” to ¼” from the top with the top of the master cylinder level. Use the brake fluid that your owner’s manual recommends for your bike. If your fluid is brown or cloudy, flush the system with fresh clean brake fluid.
2) There is a 0.040” vent hole in our master cylinder lid. This vent hole needs to be open in order for the vacuum diaphragm lid gasket to function properly.
3) If you are short & need to move the brake arm up to reach it more easily, the brake push rod length is NOT the correct method adjustment.
Hope this helps,
Troy