Alright so I am an owner of a Honda 400ex i believe it was manufactured in 2000 but i may be wrong but thats not the point im looking for a general idea of why my ATV is acting strange. Alright here is the scenario, My 400 runs like a champ but eventually all motors get hot, so after mine gets to a normal running temp that all ATV's will get, when the motor goes below a certain RPM rate, it just shuts off, now idk what this sounds like to you but its not right. If i pull the clutch in just to kinda slow down and start using my break as soon as the Motor Rpm's get low enough it just shuts off, after it starts rolling at a slower pace it just shuts off, now i am really not capable of knowing whats wrong so please help me if anyone knows, if you need anymore info on it just let me know. I wanna do a rebuild of it then start racing ATV's

 

Welcome to the forums.


Since you didn't say it had any mods done to it, I'm going to move this over to the Honda section. You should get a better response over there.

 

Start with the simple stuff first. Check you gas tank vent hose. Is it kinked or clogged?

 

Like Scooter said a list of mods would really help. Here is a list of things I would check. 1) air filter, how dirty. 2) Check the fuel flow out of tank.Turn the gas off, pull the hose from the tank to the carb and turn the fuel on. 3) Check the carb itself, is the carb seated in the boots properly, adjust idle screw, clean the carb and check the pilot jet. Sounds like your carb may be dirty.
If you have no mods and it runs good until you let off the gas its odds are its a carb issue. BTW if you look on the front of the frame you should find a sticker with the year on it.