You got it - the left lever is traditionally the clutch lever, it just happens to be attached to the rear brake as a parking brake.
Only Polaris has the primary brake lever located on the LH side - with certain exceptions; Honda, Yamaha and the other ATV's have the front brake on the right, a foot brake for the rear and a parking brake in combination with the clutch lever on the left. Some models of Honda and others with semi automatic transmissions, have the front brake on the right, a foot pedal for the rear and a parking brake only on the left. Some people use the parking brake as the primary method of applying the rear brake and complain that it is almost impossible to lock up. When they learn to use the foot pedal, locking the rear brake is easy.
The switch on the 'clutch lever' is primarily to allow starting when in gear. Only Yamaha had to goofy setup where the 'clutch switch' affected the ignition. The eliminated it a few years later.
The switch on the T-handle activates the reverse light - it can only be shifted to reverse in neutral, but there were a few models that had to be shifted into reverse when the transmission was in low gear and even a few where reverse was selected on the output gearcase allowing 5 forward and reverse gears. It's akin to putting a Harley Servi-car 3 speed with reverse transmission into an old flat head 45 motorcycle making a motorcycle with a reverse. Was a PITA to use with a foot operated suicide mousetrap clutch, but it was commonly done for motorcycles with sidecars and the occasional clown who thought it was fun to ride backwards on two wheels.
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