What engine oil should i use for a Honda monkey engine?

What engine oil should i use for a Honda monkey engine for a mini bike / chopper? Also i don't have a manual or anything to tell me what to use! (1P39FMB) is on the engine alos

10W-40 API SG or 10W-40 API SL conventional oil.

Depends on which engine you are asking about. Go here and download your owners manual which will list the correct eight oil.

I'd use Shell Rotella 20W-50. It is wet clutch safe and not too expensive.