i left my 4oo ex at a friends house for a month now i pick it up it wont run right it starts great but when i try to frun it hard it pops out the exaust and falls on its face and wants to die i thought it had water in the tank so i draind it still the same it has a t 4 pipe dyno jet kit k and n filter has it all not sure whats wrong it pops so loud out the exaust it almost souds like a two stroke anyone know what the deal is i sur would like to know thanks

 

Sounds like a carb problem.....pull out the drain hose for the carb and see how much fuel runs out....if it is just barely dripping, you need to clean your carb....if the system checks a-okay, check your valves.....

 

my money on clogged carb also.

 

well thats what i was thinking was the carb or the valves but really dont know how to mess with the valves

 

thanks guys i will check out the carb first hope its not the valves

 

I would try to clean the carb and filter because it sounds like its running lean from a lean condition

 

I hadn't touched my carb in 6 years....one day, go to fire up the quad....Kicked over only when I gave it full throttle......Local shop overhauled the carb, problem solved....

 

i forgot to say that when i first start it it seems to run fine but after it gets warmed up thats when it seems to run like crap i checked the plug its fine i checked the carb not a whole lot i just dont like to rip into things like that but i looked it over it didnt look dirty i took the airhose and blew it out a friend said it may be the valves and i dont know how to mess with them bbut i think im gonna start with the carb and dip it in some chemicals that a friend has it just makes me mad one day it runs great then i start it up then its crap thanks for all the help guys i will try all i can im a mechanic on cars guess its time to figure out the bikes lol

 

When you think about it, theres only two parts that can make your quad run semi-correctly, the carb and valves.....and air filter, if you want to get technical.

 

use some seafoam on it