This is a great post I would like to hear more from guys with experience. I have heard stock hondas run a little rich also. Actually I just changed out my plug and from the looks of the old one it was running a little rich, i had 100 miles on the quad. Yes rich is better then lean. I want to put a hmf on mine as well and was wondering due to it running a little rich would I need to rejet or would it be ok. Good Luck