A lot of that era euro stuff runs 25 to 1 for road use. If your racing i would go to 20 to 1. Yes rings wont bed in with sythetic and you will get glazing. Some people say bikes smoke too much with 20 to 1 but when ever i run bikes with that ratio with just a basic 2T oil there seems to be stuff all smoke at all, even at idling/low revs.