1975 Moto Oil Change ??

[Neb954]

I've been riding my gf's 1975 Kawasaki KZ400 around town every now and then. Anyway she changed the oil last year with what she thinks was 5w-30.

I would like to change the oil on it and from online it sounds like it calls for 10w40 ro 20w50.

Anyone have an 'older' bike and what oil do they use on it?

If memory serves me correctly the Valvoline HighMilage Synthetic blend oil doesn't have any of the additives that a lot of the 'normal' oils have. (run it in my 91 stang)

Any input? Or do I just use the same oil that I run in my 954?

[brennahm]

Weight isn't terribly critical. I'd use whatever motorcycle oil you prefer.

[TFOGGuys]

Given that it's an older, air cooled bike, I would run whatever brand of motorcycle specific oil you prefer, in a 15w-50 or 20w-50 during the summer months. Air cooled engines run significantly hotter than water cooled ones, and as a result, lose more oil viscosity. Motorcycle oils differ from recent(API SH and later) car oils in that they contain relatively high levels of zinc diphosphate in the additive package (a no-no in cars with 3 stage catalytic converters) that acts as a high pressure lubricating agent to prevent galling and pitting of the transmission gears under load.

Also, some older bikes will exhibit a tendency to leak more easily with full synthetic oils, so a semisynthetic blend or mineral based oil might be a better choice.