'Modern' rear master cylinder replacement, swing arm bearings, and other rebuilding questions

Hello all, I've been a long time lurker of this great site, and now that I have finally bought most of the parts to rebuild my '78 KZ650C3, I have some questions I hope you can indulge me with answers to.

1) I probably should have asked this earlier, but what is a relatively straight-forward master cylinder that I can use for the rear disc? Mine is locked hard and very very corroded, and my friend's 70 KZ750B has the same MC and the same problem. Looking for something that will basically bolt in place as I dont want to modify the frame really, but i'm open to messing with the pushrod to make it work with whatever I put in there.

2) How the heck are you supposed to assemble the needle-bearing set for the swingarm shaft? Do I need to press them in place? If so, any tips to do that with normal hand tools?

3)What tires do you guys like for your 650's? Mine will be ridden mostly for commuting 26 miles/day, but, I do live within an hour of the Dragon, and then there's other great curvy roads in the Smokies that I like to drive/ride, so some performance potential would be wonderful. (Not a knee-dragger tho, no super soft compound needed ) If I can get 4-5k out of a set i'll be happy.

4) I know this isn't a 'chassis' question, but if someone happens to know the answer i'd appreciate it, otherwise i'll post separately in the carb section later..... but here it is ----> What jets should I order (range of 2-3 sizes is fine, i know it's just an estimate) for a KZ650 that's all stock aside from pods (emgo) and a Kerker/Mac 4-1? I've found anything from 110 to 117.5. Jets that come w/ the rebuild kit were 102.5


I appreciate any bits of knowledge passed my way. I'll post up some pics as this project gets going. It should be interesting to say the least.

Before resorting to replacement, could attempt restoration of existing rear m/c and caliper. Some of these can look pretty horrible yet still be repairable, depending on extent of pitting inside the bore. Good Luck!

I have replaced mine with a newer type with a reservoir. I believe it is from a GPZ, as long as the holes line up where you bolt it on you should be OK.