Does anyone know a way to do so, or to wire it up to stay on when the bike is on

 

I forget the specifics of the wiring, but i'd simply find the constant positive to the fan or the sensor for the heat. Do so by turning the bike on and checking which has a constant 12~ volts. Then find your negative (find what has continuity to the frame, which is ground).

The fan should have a positive and a negative. I don't know the colors off hand. Disconnecting one and seeing if it goes to the frame (ground) should tell you which is which.

Next up, run from your positive to the switch. Run from the switch to the fan's positive, and make sure the fans negative line is still in place.


Viola! Done and shredical!

 

You might look at the fan relay. On my 08 1kRR the fan relays have constant 12V power and the ground is switched. I installed a manual switch by running a ground wire through a 3-way switch and over to the relays so I could turn one or both on whenever I want to, thus the reason for the 3-way switch. If yours just has one fan you'd just need a single on/off switch.

The fans still come on automatically if the temp gets too high and they will turn off if I turn the key off at the ignition. Running 12 volts directly to the fan(s) through a switch could leave accidently them running after you turn your bike off if you don't hear the noise and drain the battery.

One of these days I'm probably going to replace the switch I originally installed with an LED 3-way so that I'll know whenever the fans are running as I'm riding, whether I turn them on manually or not.