Hmmm. I had to replace shift forks in an 08 that was doing that. It still ran and drove, but just made a horrible noise.
https://www.hondaatvforums.net/foru...5-420fm-rattle-under-throttle-bottom-end.html
That was on a footshift bike, driven by a kid who was rough on shifting. On an ES machine I have a hard time thinking that would be your issue.
Have you checked your muffler clamps to make sure one hasn't rusted through allowing it to rattle? I know it sounds silly but you'd be surprised at the noise something like that will make.
https://www.hondaatvforums.net/foru...5-420fm-rattle-under-throttle-bottom-end.html
That was on a footshift bike, driven by a kid who was rough on shifting. On an ES machine I have a hard time thinking that would be your issue.
Have you checked your muffler clamps to make sure one hasn't rusted through allowing it to rattle? I know it sounds silly but you'd be surprised at the noise something like that will make.
