Motorcycle Start Button to Starter Solenoid Circuit

[Sportyrider]

The circuit to engage the starter solenoid on my chopper failed inside the controller. So I would like some help on selecting the best way to get 12 volts at about 16 amps to the solenoid using a switch that is only rated at 250 ma that switches ground to the output. (I am guessing at the amperage using the fact that it has an 18 gauge wire carrying the load to the solenoid).
Thanks for any suggestions.

[KMoffett]

What make/model motorcycle? Finding a wiring diagram will help.

Ken