Originally Posted by Bill Kapaun

I was recently bequeathed this and when you rotate the crank backwards, the chain ring doesn't rotate.
https://www.giant-bicycles.com/us/explore-eplus-3--2019

yep. Park made their chan cleaning tool to work in the opposite direction for mid drive e bikes. on the tandem I just use the back crank to clean the chain. I think the wirr sound comes from the back but not sure the clunk sure does.