With the 15/35 I'm at just below 5000 RPM. With the 16/35 I'm just above 4500. Interesting to see how they compare. The pic of a MKII with a 16 there's more room between the fender and tire. I'd like to go back to my progressive shocks while I have the RFY shocks rebuilt.
My 1978 1000 LTD has a 16” rear mag and stock is a 33T rear.
The FSM for the 78 LTD shows 15/33, which is the same as the '78 kZ1000A and Z1R. The earlier Z1/900 and later '80 MKII used 15/35. It seems like they were playing with ratios over the years, but Kawasaki didn't necessarily use different ratios for 18" vs. 16" rear wheels.
The tires are slightly different in diameter. The 16" used an MT90-16, which seems to translate to a 130/90-16. The 18" used a 4.0-18. Comparing tires, the Bridgestone BT46 currently comes in both a 4.00-18 and 130/90-16. The 130/90-16 is about 1.5" small in diameter (25.079 vs 26.496). So the RPM at 70 would be a bit higher with the 130/90-16
Noodling around with a spreadsheet, this is what I came up with for RPM @ 70 MPH in 5th gear with those two Bridgestone tires, for different sprockets. It seems to sort of compare with the engine speed numbers people have mentioned, so the math might be right.
It's raining off and on here today so I didn't get out. We need all the rain we can get....over 200 forest fires going today. The town of Lytton has been completely wiped off the map. Unfortunately the forecast is for thunderstorms, which means a lot of lightning.
Sprockets are 16/33.
I have several restored bikes along with a 2006 Goldwing with a sidecar. My wife has a 2019 Suzuki DR 650 for on and off road.