Im pretty new to this ATV stuff, but my 400 seems to file out spark plugs really quickly, after about two days the performance gets really bad and u take out the plug and its all black and wet. why is this happening? and also just today i changed the spark plug and im still having performance problems..its just not getting up to speed..any advice is appreciated

 

your jetting maybe a ways off, or your oil injection is out of tune, you may also have a broken oil inj. return spring, mine broke a long while back and lucky for me it broke in the wide open position, my bike ran pourly to till i found out why it was, i removed the oil inj. and started running pre-mix to ensure oil delivery.

you may need to inspect a few things in order to figure out what it is.

 

Just something simple....have you cleaned your airfilter...if you aren't getting correct amount of air then it can cause a rich condition as well. Have you done anything to it recently? If so what was the last thing you did and backtrack from there.

 

heres the update..cleaned the air filter..she runs like a bad *** now..funny something so simple could screw up the way the thing runs so badly..probably still need to rebuild the top end since it is 6 years old....but i would just like to say thank you for the tips...