Faults:

Minor electric problems.

Oil leak where a cylinder joined the crankcase.

Rebuilt the carbs.

Replaced the exhaust with 4 into 1.

No major mechanical problems.

General Comments:

I have owned 2 1973 Z1 900s and a 1974 Z1 900, 3 KZ650s from the mid 70s, and a 1978 KZ1000.

My last 73 Z1 900 was bought in 2000 for $800 from a college student who abused it, didn't take care of it. It started and ran like a clock. I gave it an oil change and a minor tuneup anyway.

Very scary motorcycle, 60 mph in 1st gear, had it over 120 mph with more to go, but chickened out.

Go fast, no stop. Brakes were crap and installed a second disc on the front to get a little more grab.

Frame was squirrely and would wind up under acceleration, had to be careful in the curves.

Put low short bars on it to get down a bit out of the wind stream.

This bike (all of them) had a bulletproof engine, started every time and ran like a watch. Very easy to tune.

Great to posture around town. No guts in the muffler, and when it started up heads would turn all up the block. Just idling it sounded like the monster bike that it is.

Great fun for about 100 miles, and then your butt would go to sleep and your arms flop while your hands got numb. A half hour break for fuel and a coffee would cure all that, and then back on for more serious fun.

My first '74' leaked oil from the where the cylinder head joined the crank case, I sold it and bought the '73'. I learned to do most of my own mechanical work, including carbs. These bikes are very easy to work on. The electrics always baffled me and it went to the shop for that.

When I retired and moved to Phuket, Thailand, I sold two '73' Z1 900s, (one was a mostly all there parts bike) a '78' KZ650 and a '78' KZ1000. Dang! Wish I had imported them. Both the Z1 900s were bought and sent to Japan to be restored and sold for big bucks to collectors.

I have owned two Yamahas, a 650 twin and here in Thailand an early 80s engined early 90s frame xv750 Virago. I owned it for 3 years and it was in the shop for at least one and a half years of the time I owned it. I now have a 8 year old one lung 175cc Kawasaki Boss that has never failed me.

I saw a 74 Z1 900 here a few years ago. I gasped and offered the guy whatever he wanted for it. He just laughed. He had imported it from the US.

The old Kawasakis are the best.