[pat in Santa Cruz]

3 and 4 look oily too, which leads me to suspect the scratched bores and possibly worn rings. I don't like home fixes for valve seats. If you're installing new valves, you should replace the guides. Then the seats should be cleaned up, centered to the guides and re faced by a machinist. If your rings are shot and the cylinders scored as much as they seem in the photo, new valves will increase the oil burning. A proper valve job means pulling the engine. If the cylinders are as scored as it appears in the photo, you might as well bite the bullet and consider a rebuild. Or button it up and drive it through this touring season as it is and have it rebuilt next winter.