Oil. What grade in old bike?

[kiwi cowboy]

Ok cb900f honda 83000km's and does use oil but my question is this.
I am useing mobil synth S in it now being an older bike is this the right oil for it or would another type of oil be better and slow the usage?
It never blows smoke so not sure were its burning it [rings or valve guides?].
cheers for any coments

[RobRod]

Using a synthetic is perfectly okay as long as the grade is okay. Years ago when those old bus were still reasonably new I used to run castrol grand prix in them, seemed to work although oils have come a long way and the Bol d Or was in the era of API 'SD' and 'SE' rated oils. Ny bet would be to run 10/30, 10/40 oil that can handle being around a clutch without causing it to slip through too many friction modifiers. Whether mineral, semi synth or full synthetic is up to how much you want to spend and how often although a good mineral with frequent changes of both oil & filter is best.
Sorry for the long post.

[Bonez]

Ok cb900f honda 83000km's and does use oil but my question is this.
I am useing mobil synth S in it now being an older bike is this the right oil for it or would another type of oil be better and slow the usage?
It never blows smoke so not sure were its burning it [rings or valve guides?].
cheers for any coments

Here's a usefull resource for the CB1100/900/750 range. http://www.cb1100f.net/

10w40 and 20w50 is suitable according to the manual.

[MSTRS:Me]

Probably not the best using full synthetic. Plus it costs way more than suitable mineral oils.