Welcome to the site from the U P of Michigan. Sorry to see you are having trouble with your new to you Wing. There are several different steps and adjustments that could cause your problem. I know you said the starter button relay clicked, but also did the neutral lite turn off and reverse lite turn on? Did the headlights turn off? Was their plenty of battery voltage? Without sufficient voltage, such as right after starting the engine, reverse has a hard time working. If none of this helps, look at the troubleshooting guide for your bike on reverse problems.
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