Depends on the speakers and the helmet. The soft,fabric speakers can be simply moulded into position and stick with the Velcro. Some helmets, like shoei's open face platinum r are designed to fit speakers easily.

Thanks Mickle Spook and Fatbat.

i still like maps, i have had bad experiences useing GPS in cars, hate them. a good map will never let you down.

& they can't track you.

but liked the read, still would not get me to put on on a bike.

A GPS doesn't track you, it tracks the GPS satellites. Airlines use GPS to tell the pilot where they are, but they don't transmit that position back to base. For the sake of a $2000 piece of commercial grade hardware the size of a cigarette packet, and a $1000/yr subscription they could have known within a few kilometres where that plane ended up. Buy shares in commercial GPS companies because airlines will be forced to install them on every plane from now on.

unless it also got turned off

Hi folks. 

Just saw this on gumtree for $250

Second hand Garmin Zumo 550 waterproof GPS for motorbike. I've got one myself. They are a great simple unit. An old unit in the scheme of things. Usually come with free lifetime maps. (just updated mine this morning) Mount on most bikes with Ram or handlebar mounts and can easily be swapped between bikes. 

Located Noosa QLD area. Nothing to do with me but could be an option for one of you.

https://www.gumtree.com.au/s-ad/tinbeerwah/audio-gps-car-alarms/garmin-zumo-550-gps-navigation-for-car-and-motorcycle/1138308074