1998 Honda 300TRX - Hesitation Or Skip

[HanksRide]

I have a 1998 300 fourtrax that I have owned since it was new. It has done its fair share of sitting over the past few years but I have started and used it atleast 4 to 5 times a year and sometimes pretty hard around deer season. For the last few years it has had a skip or hiccup when running at half to full throttle (steady throttle). This thing has always started perfect, idles perfect and takes gas great, runs great except for this hiccup when holding it at a steady throttle under load. Sitting you can hold the throttle all you want and it purrs like a kitten. I have done the complete tune up, cleaned the gas tank, replaced a broken choke cable where it screws into the carb, took the carb off and it looks extremely clean, blew out the vent lines. I have also ran it with the gas cap off and I believe it runs better (hiccups less often) with it off then with it on. I have ran seafoam through it. Done about all I know to do except take the jets out of the card and clean them. Like I said the carb looks clean with no varnish buildup of any kind in it.

Any ideas would be helpful.

[oxidized_black]

have the valves been adjusted at all ?