Thanks a lot guys.

I know that I need a new head, kit, piston and many other things.

I'll try to make a comprehensive list tomorrow and post it.

The situation does pretty much suck as I use the bike for transportation (and intense leans in upstate New York-yes you can put your knee down on a gs) and the season is slipping away, but at least I have time to fix it now that my semester is over.

I don't really have the funds for a new engine and will definitely try to repair this one if possible.

Thanks again for the advice and encouragement.

p.s. I noticed that the mechanic I bought it messed around with it rather than rebuilt it.  Besides for the obvious, he reused all of the old O-rings  (they were rock solid), and definitely changed the millage on the bike (when I bought it had 1000 miles on it, but from the abrasion to the cylinder--even on the good one--it's clear that it had more than 15,000+.

O.k. guys,  here's the list of what I need so far:

1.  A "complete" cylinder head (must have all the valves).

2.  A top end gasket kit

3.  Four  new wristpin circlips

4.  New pistons and ring sets, next size up, (If I decide to rebore the cylinder), or pistons and rings set with new cylinder (if I decide not to rebore the cylinder that I have)

I'd prefer to get the original size pistons and cylinder since I have no idea where I could rebore a cylinder in NYC, how much it'd cost, what next size pistons I'd need, and there's the chance that the place I find will mess up.