For those vintage engines in which the crankcase and cylinders are still two pieces, the ring compressors sold by the factories are really handy, if not mandatory. Here is a collection mostly from Honda and Yamaha. Each set of two matched compressors in my collection I marked and color-coded, and fits a nominal range, such as 65mm~67mm. You don't know how painless installing a cylinder block can be until you try these! Too bad they are long discontinued. But they still can be found here and there.