+1 My 12r is the same... I believe from what i have read that hot running is common 12s, My fans cope very well though, they seem to keep the temp needle 1 below hot but when you get on the open road it cools straight away which is fine in my book.Kinda having the same problem after i changed the coolant. But mine is fine while riding, but at light's the temp jump's up quickly. City riding the fan almost run's constantly.
Basically how i did it. i still think there's air trapped because every time the fan came on it would spit coolant up. i'm running coolant, distilled, and water wetter. How many bottle's of water wetter do you run? Also if the bike is running lean, would the also cause it to run hot?You gotta burp the cooling system by letting the bike run and get hot with the cap off.
Make sure the overflow tank is not dry or you'll just suck air back into the system as it cools.
The 12 has an air pocket in the cylinders that'll trap air until things start getting hot and moving around. Lightly tapping on the cylinder bank with a soft rubber mallet seems to coax the air out as the coolant reaches hot.
If you really want to cool her down, run distilled (always used distilled regardless) water and Water Wetter. You can add some coolant if you like, but the 50/50 mix is a killer on heat transfer.
In the summer I run 1 cup coolant, and the rest distilled water/Water Wetter mixed as recommended. Makes a HUGE difference. Just do not forget to flush it and 50/50 anti-freeze it well before freezing weather if you live in the snow belt. A cracked block is no laughing matter. ;-)
I also wrapped the header, but it's only down to the collectorWell, I've never met a zx-12 that doesn't run on the hot side.
Mine will blow the fans all day long in stop and go traffic with coolant in it.
I use 1/2 a bottle of Water Wetter, which is half what they recommend for a car. Trust me, it makes a HUGE difference over 50/50 antifreeze.
Water Wetter claims 20 degrees F cooler and I believe them.
Also, I wrap my header pipes. That makes a difference too, not only on the heat pouring onto your legs, but the air-box is cooler which = more HP.