interesting point about the missing ring from beneath the valve guide,i could see why oil could be sucked down into the cylinder,yes i did fitted the new guide myself,did it years back on a cb125 twin,heating the head up in the oven till cooked lol and putting the guide into the freezer then drifting the guide home,it lined up nicely and im sure i remember fitting the washer first,tapped it in nice n straight using a drift that fitted on the outer shoulder where outer valve spring would sit then using course grinding paste until a nice even unbroken seat then fine grinding paste,ive heard your meant to recut a new seat but didnt have that type of equipment,but got a good seal good compression.
