1981 KZ440 Engine Rebuild

So i'm working on rebuilding one of my KZ440 engines, and i've never done this before. i have two set up 440 engines so i hope to make one good one out of the two.

the one i'm working on was ridden this year. the bike was never fully up and running and functioning properly. there was a knocking towards the top end of it since i bought it. i had it up and running at about 20mph when i heard a pop and the bike locked up on me and i skidded to a hault. walked it home and when i went to try and start it again, the starter just clicked ever since.

so i started ripping it apart to see if i could diagnose the problem.

here's some more info:

1981 KZ440 LTD - Chain drive, 2 Cyl, ~12,000 miles

the only thing missing (besides the engine now . . .) is part of the air filter + element. i have the air box on it, but it's missing an attachment that houses the actual filter. pretty common to be missing off of these bikes (used) from what i've read.

i started pulling the engine apart today. its looks like its the 1st time its been apart, so if anyone can give advice and/or suggestions if anything looks funny (since i've never done this before . . .) it would be much appreciated.

here goes:





















i have the piston bosses off now. i haven't seen anything blatantly broken yet. there seems to have been some rubbing against the right piston shown in the picture. and the left side seems like its getting more oil than the right (the right side being pretty dry actually). i'm trying to find the source of the original knocking sound i was getting. maybe thats what the "rubbing" marks are from?

*sorry for the cross post from kawi motor forums to anyone who reads both*