Hours vs. Miles

[Big Fred]

I log my miles after every ride/race. Is there anyway of knowing how many hours on the bike by caculating the miles.
Thank You.

 

[velosapiens]

you can guess. i know that in the deep woods we have in norcal, i usually average 10-15 mph. my 02 300 exc has about 6000 miles on it, so i estimated somewhere around 450-500 hrs. i'm gonna put in a new top end sometime soon, but the bike still runs fine. of course i short shift and lug it around alot.