Mel, I don't really see your answer given here. I have a 1968 CL175 and the needs of it are the same. I suggest a motorcycle specific oil in the 10W-30 or 10W-40. I would go to my nearest Honda, Yamaha, Suzuki, or Kawasaki shop and pick their brand. None of the big 4 makes oil - but they do license their names and provide factory warranty for their machines using them. When you buy a brand from one of them, you will also get motorcycle specific oil which is free of the "Energy Conserving" additive packages used in today's automobiles. There is a difference and that's why I suggest a motorcycle specific oil - one carring the CCMC G-5 or JASO MA standards. These will be free of the additives common to cars, but not best for wet clutches. I use only Motul synthetic - but it's a personal preference.
Anyway - even more improtant than what oil - is changing it. You are absolutely right to want it out of the engine. The moisture/humidity of the incoming air/fuel mixture is mixed with the sulfur in gasoline. This generates sulfuric acid during combustion. The PH of the oil will change and turn to a metal surface-eating acid the can/will cause damage. Engines that are run short distances and aren't ran long enough to get rid of all and any moisture are even more susceptable. It's best to change it and kick it through several times - without starting to get a good splash everywhere for it's long rest.
Best of luck to you and enjoy that CL come Spring.
Regards,
Gordon
