Motorcycle Repair: oil api rateing, friction modifier, 1994 honda magna

Question
1994 honda magna, my question is can catrol sae 10w-40 api-SM, be used in the place of honda gn-4 oil. HONDA RECOMMENDS A SG OR SF API . THANKS

Answer
 Jonny,
 engine oils such as API SJ thru SM will contain some level of friction modifier. While the friction modifier improves fuel economy, it is not compatible with wet clutches used on motorcycles. The friction modifier causes the wet clutch to slip. This is especially true if the motorcycle manufacturer recommends using only engine oils carrying API SF or SG Service Categories.

hope this helps

Eric