'79 kz400 top-end rebuild

so i was told by the previous owner of my newly bought kz400 that there is a leak at the head gasket on the block. that said, the plan is to replace the gasket. so what is the plan of action while i am in there? should i look to change anything else while the motor is out of the frame?

also, i'm having a bit of a hard time finding parts specifically for my bike. it seems most parts are for 77-78, never reaching 79. am i looking for the wrong year, or will most of, if not all, parts listed as 78 work on a 79?

Is there some reason for removing the engine from the frame? That should not be necessary just to replace the head gasket. Ed

well, i initially wanted to disassemble the entire motor and have a look-see as to what's going on in there. the odo reads 26k, and me being a stickler for a properly maintained motor, i'd like to see what i can do to make sure it runs like a swiss watch. i don't know if the previous owner(s) have taken good care of it, so i'd like to inspect it myself. if that means stripping it and rebuilding, then so be it. but if you more experienced guys think it's unnecessary (kind of like how i just learned it is for replacing head gasket!), then i'll cease and desist.

also, i found this gasket kit and this bolt kit for the rebuild. anything else i need for the job?

Have you seen this leak?
What is leaking?
Maybe a pic.
Have you done a proper compression test?
And like I was told long ago,..if it ain't broke don't I fix it.

....and if if ain't broke don't break it. Ed

yessirbob. heck, i just noticed that there's a leak from the drain plug as well. but unfortunately i did not get to take a picture this morning. the entire bottom of the motor has a layer of oil and dirt. while i'm at it, the drain bolt is lefty-loosey, right? i've read some things on these motors are... backwards, that's why i ask. i couldn't get the drain bolt off for the life of me. think i'll use a breaker bar tonight.

i am going to perform a compression test tonight. what is a good range for compression? will update with results.

Yes, lefty-loosey. (Counter-clockwise to loosen.) Ed

alright alright, so i took the head and barrels off and disconnected the pistons. everything inside around the crank looks clean as a whistle, and the only parts that seem to need a cleaning are the pistons + combustion chamber on the head.

i'm planning on going at the carbon with some carb cleaner and a SS brush. if there's a better way to do it, i'm all ears.

also, there was a leak at the head due to a ruptured gasket. glad i took it apart to where i did, because the gasket for the barrels was pretty nasty, too.

edit: also, does anything in these pictures look like it needs to be replaced to you guys with the trained eyes?

piston rings maybe?