Yeah, since the Rincon is fuel injected, it should have a throttle position sensor of some sort. There is a link to a manual for a 650 Rincon at this site. I would say the fuel injection would be basically the same on the 680.
YOu can actually clean the throttle body like you do an auto but sometime you can do whats call the wiggle test on electronic components such as the TPS, I would unplug it and pllug it back in soetimes that will clear an issue.
if it has a tps it should have a idle air control valve.
The iac is what controls the idle,not the tps.The tps could cause your problem but if I was a betting man I would remove the throttle body,clean it and see if the iac is stuck open.It is a piston the moves in and out to let air in and adjust the idle speed.