Front wheel and tire for my pro street KZ1000

I have a 1977 KZ1000 that is stretched 13" over with 300 Avon rear tire on a jackshaft swingarm. The rear wheel is a 5 spoke Weld Racing Charger 5. I found a front 5 spoke KZ/gpz 550 front rim that looks very similar. The front rim is 1.85" and I have a 100/90v19 Avon AM26 tire. The 1.85 rim is recommended for a 90/90v19 tire, but i think thats a little too narrow. Would the 90/90v19 be too narrow for the KZ1000. Im not doing winding roads but want to ride and have adequate rubber on the front too. Of course I'll have the front rim chromed to match. Tom

a 1.85x19" rim is the stock size for the KZ1000, so you could go to a 100/90/19 no problem. if you want the fatter look you can have the wheel widened, but that ain't cheap.

Actually, the 100/90-19 tire is the correct size tire for the 1.85 front rim. The 90/90 is too narrow. I've been running 100/90-19 front tires on my 1977 KZ650 (with stock 1.85 rim) for 39 years. Ed

Thanks gentlemen. Just wanted to make sure.

Would a 18" 90/90v18 be too small of a tire for this bike mounted on a 1.60" GPZ305 5 spoke rim? I mean, should i use a bigger tire for MY bike cause I know the GPZ305 is lighter but the wheel is the 5 spoke single rotor design that fits the look I want. I have a GPZ550 rim in 19" but it is a dual disc wheel and I'm using single disc with trying to keep the weight down. The bike should weigh a little under 500lb when done.

You can use the GPz550 wheel with just one rotor/brake.
Remove one side, cap off or redo the brake lines.

oh, i know i can use single rotor. My kz has single outlet brake block, but i was looking for a wheel designed for the single rotor just for the cleaner look. Ill probably use the 550 rotor and have an aluminum cover fabbed for the other side.

The kz650 B models came with a single rotor in some markets, and a cover on the hub on the other side.
650 wheels use a 4 bolt brake rotor mount, until sometime in the '80s where they switched to 7 bolt.
550 is a 7 bolt rotor I believe?
Did some 550 models come with single disk brake up front, and cover on the other side.
Sorry, not too familiar with the 550s.

oh, i know the single disc rotor wheels that are out there but I was wanting to do the 5 spoke as my Weld wheel is. thanks,though.