Hi Sean
I would run the Blade on Fully Synthetic oil. The Super Dream and the 550 I would run on good quality mineral oil, with regular changes at about 1000 miles on the 550 and Super Dream.
Grizzly
Some models mentionned may not have been available in Canada. Now that you read Grizzly specific advise, (which appears to be quite wise), I will limit my contribution to general guidelines about using synthetic oil on old motorcycles, so you that can make your own opinion.
I'm not a mechanic or motorcycle expert, but I got four Honda's (CB175 1971, Goldwing GL1100 1981, CH250 1986 Scooter and CM400T 1980). Here is what I learned by digging into the service manuals and several articles and asking expert mechanic advise:
Recommendation #1 : Any wet clutch must be kept into the same type of oil it was started with. The fiber compound of a wet clutch is loaded with the original oil. Beware: If you switch from mineral to synthetic, your wet clutch (soaked in motor oil) has good chances to start slipping.
Recommendation #2: If you use synthetic or semi-synthetic, make sure JASO is listed in approved test. This means anti-friction additives are calibrated to work with a wet clutch. Synthetic oil for cars is NOT compatible with wet clutch.
Recommendation #3: At least old Honda bikes (such as CB) and possibly newer models use gaskets that are designed to swell by absorbing engine oil in order to make a tight seal. Changing the oil type for synthetic may cause engine gaskets to start leaking... interested ?
Recommendation #4: keep on the same maintenance schedule with synthetic... do not space up oil changes. Beware that some model have different filters for synthetic oil, there must be a reason.
