BrettZZR wrote:Gos - out of interest, what is it on the head that is different?
(-8
inlet manifold design. The head changed to a downdraught design with the first ZX10 of 1988. All the intakes were angled up at around 45deg compared to the previous GPz1000RX and GPz900R heads, which had the carbies in the normal horizontal position behind the head.
ZX10 and the subsequent ZZR1100 and 1200 motors all use the head with the angled inlet ports. The ZRX does not - it went back to the earlier design with the carbs horizontal behind the head. Internally, the heads are pretty much the same as far as everything else is concerned....maybe some slight changes in valve sizes and cam profiles over the years...
There was also a GPz1100 in the model range during the mid-90's - this used a horizontal design for the inlet tracts.....but basically the same motor as well.
You can also swap cams around between these motors easily - I think the go is to use ZZR1100 cams in the ZRX motor for some better top-end. But you can't fit a ZZR1100 head to a ZRX motor in a ZRX frame - there is not enough room for the downdraught carbies.
There are blokes in the US who are pulling 150hp out of old 1986 GPz1000RX motors using almost all standard Kawasaki parts....
