Any body have their rear brakes lockup?

[psicorp]

Crazy thing happened yesterday.  I haven't been riding the 748 too much lately because I have been riding the mountain bike to work.  But I thought I would ride the 748 yesterday to work and got about 1 and half from house and notice bike acting weird then all the sudden the rear wheel locked up and put me to a complete stop.  Luckily I was only going about 40 mph.  anyways I shut it down and I cant move the bike one inch.  A guy stops and helps me move it to the center turn lane and nothing I can do will move the bike.  I can clutch and change gears and attempt to pull away but cant go anywhere. 
   
I start thinking it is the rear brake and start messing with master cylinder hoping that will free up the pads. but nothing.  after messing around I jump back on and can move a bit and I start to go a bit and again it locks up.  I call my wife to come pick me up and before she gets there I can rock it back and forth a bit and try to take off and get about 200 feet down road and lock up again.  This repeats a few more times until I can park the bike on sidewalk.  Wife brings me home and I drive car to work. 

After work I retrun to the bike and put it neutral and rear wheel is free as sin.  so I ride it the last mile back home.  So my thought are some reason the rear brake is engaged and after a certain amount of time the pads over heat and clamp down.  The reason I could move down the road was it was like 10 minutes or so between when it locked up and they cooled down enough to all the wheel to roll.   After a few hours when I picked up the bike they were totaly cool and I could ride it all the way back home.   

Does this seem to make sense to anyone else?  Also, is there anything I should check, maybe tranny?  I don't think it is it because  on way home made to 3rd or 4th gear and it was shift fine.  Clutch engages and gets in neutral just fine.  Has anyone else had something like this?

I plan to replace the rear pads and rotor, should I look at the calipers?  I will probably do the front just to be safe and change the fluids.

Luckily it was the rear and luckily no one was riding my tail.  I didn't dump it or anything so it was basically like doing an emergency stop and all is fine with the exception of my pride. 

[Fresh Pants]

Manny had a similar issue on his yeller bike a little while ago after installing rearsets.
I think it was a plunger/master related issue.

[psicorp]

I am kindof thinking that, for I drained the Master cylinder to plunger, but that didn't free it up.  For the pressure was between cyclinder to the calipers.  I will check the plunger out also.  thanks.

[Manny]

The deal with mine was that the plunger was adjusted too tight. It needs at least a mm or two of free play before the cylinder engages. More free play than you might think if you're adjusting it yourself. It doesn't take much for that plunger to actuate the cylinder and make the pads rub on the disc continuously. I ended up replacing the pads after my little "episode," just to be on the safe side.     If you just messed with the master cylinder, I'd suspect this to be the most likely root of the problem.

A little brake cleaner in the calipers might not hurt either, just to make sure that nothing is clogging them up and causing them to stay clamped down after the pedal is released.

Your technique could also be a factor here. Be aware of where your right foot is at all times. Make sure your foot isn't putting pressure on the pedal without direct intention to engage the brake. Use your rear brake sparingly. At no time (under normal riding conditions) should you be using just your rear brake. The moral here is that the rear brake has alot less stopping power than the front, so it will build up more friction and heat in a shorter amount of time than the front.

[psicorp]

Rear brake is only used sparingly.  Do know you get 75-80% of stopping power from front brakes.  I think your observation about plunger is correct.  The guy I bought it from never used the rear brake and pretty much had is adjusted where it was pretty much not usable.  I do like the rear brake especially on a superbike in traffic when I come to a stop on a hill as I can put bike in neutral and take my hands of the handlebars and just use the rear brake. 

I suspect that I may have had it adjust improperly and it finnaly worked itself to engage and hence cause my brakes to overheat after a few miles. 

[Scottish]

I forgot to put the buddy bolt on mine when I was reassembling the bike, I had a lock up too. From the engine vibration slowly tightening the bolt on to the plunger. I didn't post it earlier cause yours sounded different with it releasing after a cool down. Good luck.