I’ve made some improvised plugs and cut out a set of covers from transparent plastic to protect all essential surfaces of crankcase from glass blasting and to minimize penetration of glass beads into crankcase.
Then I loaded KZ650 cases onto my Zephyr 750 and rode to glass blasting workshop. After work was done crankcase looked much better. Now cases were as clean as possible from both inside and outside. I removed all plugs and covers. Sure, all the way I used fresh rubber gloves to keep aluminum clean and degreased.
I accurately packed crankcase and went with it to paint shop. Earlier I experimented with engine paints, but after Honda CB815 project I decided to stick with Eastwood engine paint. Their universal aluminum color is exactly shade of silver I like and it’s quite close to silver that Kawasaki use for painting engines, only a shade or two lighter. Painter did the work well and I especially glad that he prefers to paint halves of crankcase separately. That’s essential for ideal result.