I remember reading this from the ZRXOC when I first researched the problem with my ZRX. Don't know how much truth is in there but interesting to here from others with the same bike. Hope this is useful to someone here. Link to full discussion below.
http://www.zrxocboard.com/board/showthr ... nd-pitting"Camshaft wear is almost exclusively a 1200 problem, you won't ever see a set of worn ZRX1100 cams. You do get pitted ZZR1100 cams, but nowhere near as bad as ZZR1200 ones go."
"To the OP, Kaw cams pit because Kaw didn't spend the money to properly harden the cam surface and/or because Kaw's low-budget cam supplier allowed impurities into the cam metal during manufacture. All Kaws with this basic engine suffer from cam pitting, ZZRs, ZRXs, Concours, and the like. Kaw assumed the bikes would be out of warranty when the problem was discovered. It takes a lot of pitting to cause engine problems, though some say the circulating detritus can't be good for the oil pump. Kaw uses the "no harm" argument to avoid warranty repairs when the problem occurs within the warranty period, though Kaw Australia has been very good about post-warranty fixes for bad cams. Kaw loaded the problem onto the end user so you have to figure out what to do."
Cheers
KiwiMat