Can someone please let me know what is the best type of oil to put in these old engines? the oil code in the owners manual no longer exists

Thanks

 

its best to use a 10-40w motorcycle specific oil. car oils have friction modifiers in them, and sometimes can cause problems with the shared gearbox/clutch on a bike.

 

^ Agreed. Also do not use synthetic.

 

Use a motorcycle oil, YES you can use synthetic without worry. Many guys here use Amsoil Synthetic in their Hurricanes and swear by it. I use Royal Purple Max Cycle. Oh and just as an FYI, there aren't any "FULL" Synthetics out there anymore When you buy a "Synthetic" Oil, its blended. Even Mobile 1 is not fully synthetic. Except ones that are not SAE approved.

 

If you want the closest oil to the manufacturers spec, go to the dealer and buy Honda 10W-40.

 

Not entirely true. There are full synthetics but if you are not paying about $15 a quart then you probably don't have a true synthetic. If you are in Europe, then if it says synthetic then it is a real synthetic.

I've been told by a several mechanics not to use AUTOMOBILE synthetic, I accidentally left that out.

 

Yes 10w40 if you live in a warmer area. 10w30 if you live in a cooler area. Change it frequently with a new filter every time. No friction reducing additives. Check the level before each ride.
These old engines last a long time when properly cared for...