Man... I'm so afraid of working on valves or anything after blowing up a Mazda 626 that I just got the head rebuilt. I also did a tranmission on my 1993 ZX7R, blew that up and ended up with a used motor...... lol. I know what your feeling. My heart still races when I think of that ticking it made. *makes me feel like nails on a chalkboard*
I have always wondered with these bike where the cut off is as how much money to spend on repairing a motor vs replacing it with a used motor with 1K miles. I always believe that if I can get away with a used motor with only a few hundred miles is better than fixing up an already dead motor. Don't get me wrong, I would love to tear it down and learn the ins and outs. I have and it never turned out well. I just don't see it being cost effective when you have to factor in all the parts / work / tools and time needed to rebuild when the motors are less money.
Either way, I hope you get back on the road again soon. I'm sure either route you decide to take has the same end result. To get back on and ride another day!
I was able to find this.
http://cgi.ebay.com/ebaymotors/08-Ka...Q5fAccessories
Sometimes the trick on ebay when looking for parts for this bike is to search as EX250 instead of 250R.
Good luck!