Kz900 lower end questions

I was looking at a parts bike today ( kz900) late model I think it was made in 77

The guy that owns it says that he heard that 900 crank shafts are lighter then a 1000's crank shaft
Is this true?

Is it the same transmission?

Will a 900 lower end bolt up to a 77 set of jugs and head without any issues?

Will it fit into a 77 kz1000 frame without any issues

Off the top of my head the 900s came with pork chopped crank journals and the 1000s came with round crank journals. My crank was lightened by Falicon by carving my round 1000 crank to resemble the 900 crank. ( Lots more goes into it but that is the short version . ) So 900s dont have the same mass as 1000s so they can rev up easier
Dave

Here is a comparison of the cranks




Source:
www.oldkawman.com/okndcranks.html

1000 is basically a bored out 900.
900 crank is lighter .
900 crank uses 8mm alt rotor bolt and keyed rotor.
1000 crank uses 10mm alt rotor bolt and non keyed rotor.
Don't fit a non keyed rotor to the 900 crank. It WILL spin on the taper.
Heads are the same apart from the 1000 having 8mm exhaust studs.
900 cases will take the 1000 block but some early 900's need the crankcase mouths opening slightly to take the bigger 1000 liner spigot.
Gearbox is the same.
All 900/1000 engines with kickstarts will fit the 77 frame.

My KZ 1000 barrels fit the 900 case, barely. Tight fit.
Steve

To all your questions the answer is YES.

Cool, thanks for all the great responses,

The guy that has it has tons of metric parts for bikes mostly the other brands but some Kaw stuff
He has a 900 LTD that has been picked at but still has most of the stuff I am lacking for my next project,
I shot him a price that I thought was fair, of course he thinks he is sitting on gold and says he has to talk it over with his partner,
we'll see what happens.
The bike has a nice set of gauges that read 32,000 miles so if they are original I would have a fairly low mile tranny.

Thanks again guys