I got the tensioner bolt loose last night with the bolt grips. They work like a charm! Guess I'll be making a trip to Honda for a new replacement bolt.

 

Not to be cute, but a bolt has threads on outside, a nut has threads on inside. You need a tensioner nut, not a bolt. Engineers are peevish about such details.

good luck

 

You're right it's a nut, not a bolt.

 

This is entertainment. I envision the face plant. The crank " bolt " washer has a large surface area. This ,in part, is the reason they are so hard to break loose and the source of the "pop". Thats what the folks at Honda tech line say.