Id say the top one with the groove for o-ring is a 76 model.

Youd be better off with the older style kz650 forks that look like your 900 forks.
I use the fork tubes from the 650 which are around 3/4" shorter with the 900/1000 lowers,that way the 900/1000 brakes can be retained.

Ive run them on high strung 1197 streetbike/weekend dragbikes back in the day with no problems.

A big ball bearing that fits closely in bolt hole and rear axle bolt normally works

I know we just met and all,but I want to have youre children! :lol: Ive been looking for a blue 78 since around 79-80,I finally landed a mostly complete 80 z1r a couple years ago that I want to clone into my own version of what a blue 78 turbo bike should of been like from factory. My version will h...

Blue loc-tite is what I normally use,In a pinch the wifes clear finger nail polish will also work!

That is going to be a cool bike!

That depends on where youre located

Ive found of the years the secret to sealing any brand of paper gasket is to spray both sides down with aerosol "copper coat".
Let it get tacky then install.

A 3 1/2" rim with a 130 tire is usually plenty of rubber to fill a stock swingarm

Find a shop that can surface flywheels,thats where I have my rotors done.

Ive got a j with the number 5 stamped in intake ports also,I was guessing the head on my bench was an 81-82 gpz1100 since it has black overspray inside of head and in cam chain area.

Did Brian get you some gauges?

Will the axle spin with the nut removed?

Well open it already!