I’m changing over the plastics on my 04 ZX12R. I noticed a marking on the back of the cylinder head that simply said “K26-75”. Does anyone know whose numbering system that is? The guy who sold it to me said the head was ported but had no idea who did the work (I actually didn’t believe him). Any info would be great. It’s Either K26-75 or K2b-75. Thanks again.