Just picked up a new project and it's a first for me. Clutch side piston lost the exhaust valve.
Besides the basic parts(sleeves, head, piston, cam chain tensioner, gaskets) what else should I look at replacing?
Sounds like you have a fun little project. Also sounds like you have the basics.
You can pretty much rebuild them on the side of the road with plyers, a screwdriver and a rock.
Get a good shop manual! They are fun little bikes. This is a great board for seeking knowledge.
Welcome aboard!
parts source in S. Cal: https://www.facebook.com/photo?fbid=1215620473491497&set=pcb.10161636122253768