Hey gang...heres a good one...  
 i have a master cylinder that is acting very sluggish...  
what i mean is..  the piston that goes in and out when the handle is operated...  does not return to the all out position..  which in turn lets the handlever become very loose...  at times it will slowly return to the all out position..  and the brake handle is fine..  am i looking a a case of a  master cylinder wearing out.?  i do not see any dirt or rust in the reservor that may be keeping the piston from working smoothly..
in all of it's quirkyness....  the brake pressure is fine...  i hit the brake lever..  and she stops no problem...  any suggestions??

Remove the lever. Be very careful, the switch is ultra fragile. Push the piston in with a dowel or phillips screwdriver. As far as you possibly can. Odds are, you've got some minor (perfectly normal) seepage and corrosion sludge built up in the bore. Clean everything out with a cotton swab and some high test alcohol (Everclear works great, just don't drink it... ) if you have no denatured alcohol handy. Or even swab it with some clean brake fluid. ALL motorcycle master cylinders "weep" a bit in hot weather, basically enough to make things sticky but not otherwise affect operation. If the area is reall gooped up, you may need a new piston seal. From the hardware store, it's just a 10 cent o-ring or two. Let the piston out, dab some grease or )preferably) soap on the top and bottom of the lever pivot points. Grease the bolt, reassemble everything. Keep your toes crossed (your hands are too full to cross your fingers) that the brake light switch is still in one piece. Did I mention it is ultra fragile?? and will snap off if you breathe on it too hard?
-WD

If the brake master cylinder is leaking or does not build-up any pressure:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4547136910...

Hope to be of service

Greetz
Kropatchek