M/bike and car oil comparison - differences??

[ZZR]

Can anyone tell me if there is a difference between 10w/40 car oil and 10w/40 motorbike oil? Most garages don't seem to sell m/bike oil which is annoying if you need a top up.

[ZZR]

Thanks, I assumed there must be some difference and hence haven't taken the chance with using car oils.

Just means that I as my bike gets older and starts using oil I may have to start carrying some on the bike.