Hey guys,
So I've been having a bit of trouble with my front brakes  on my 1998 GS 500  and need a little help. My brakes have been working great without a problem, until last weekend. I ride over to a friends house and left it there as we went out of town. I was only gone 2 days and when I came back I noticed my front brakes being a lot higher pressure than I remember. The lever was very tight.

Anyways I got home and rode it the next day and found that the pads were completely locked to the rotor. I rode it down the street and back and there was smoke all over take place. I read online that the pistons can get stuck shut if there is a lot of dust or rust or whatnot.I didn't really feel like rebulding the pistons, and I found another caliper on eBay for about the same price as the rebuild  kit. I put the new calliper on and bled the brakes.

All good to go right? Nope. I went for a 15 minute ride and found that the pressure had again built up in the brake system and the brakes were dragging again. Not nearly as bad as the first time, but bad enough  that's off the little smoke and a burning brake smell. However,  when I went to make the return ride home, it seems as if the pressure had given a little and the pads weren't as stuck.  I got home removed the caliper,  pushed the pistons back in and bled the brakes. I realized that I had forgotten to tighten well the two bolts that hold the calliper  to the frame in place to the rotor.  Would those town bolts not allow the pistons to disengage from the rotor? By that time it was pretty dark and I didn't get much of a chance to ride it to test and see if the brakes would stick again.

I find it unlikely that both calipers have sticky pistons. Is there anything else that would cause this?  What is the heat of the motor from writing causes the brake system pressure to go up?

Maybe change your brake lines? If there is internal swelling in the lines, the fluid could remain under pressure even when the lever is released.

Never had a problem with brake hoses but have had locking front brake caused by pushing dirty pistons back into wheel cylinders for new pads.   

There was a known issue with Buells and cheap aftermarket levers where the lever held the master cylinder piston in slightly causing the pads to rub.  Over time the pads would heat, causing the fluid to heat and expand (especially old and contaminated fluid), causing the caliper to tighten, and as a fire that fuels itself it would eventually lead to catastrophic brake lockup.

If you have aftermarket levers I'd double check they are properly functioning.  If you have factory levers I wonder if a master cylinder rebuild might be in order.

I'm glad you mentioned the aftermarket lever. I've spent this summer restoring the bike and I actually did replace the lever, with one I found at the junkyard. I don't know what kind of a bike it came from. I still have the old one, I'll have to throw it on to see if that may be the problem. However all the brake fluid is very new so I don't think that would be the problem. I just don't find it likely that both caliper's cylinders were locking up

When they are locked up open the bleeder screw and if they are released it was a hydraulic lock and if they are still locked it's binding pistons.