i bought this quad a couple weeks ago, i got a good deal but the last few days it hasent seemed to have as much power as it did. its still reving fine at first i thought it was the tires spinning because there getting bald today i was climbing a hill and it almost didnt make it, usually it goes right up no problem at all i thout the tires were spinning but i looked back and they werent first gear seems alright but after that the rest dont have the power they did a few days ago. before it would pull up no prob now im having a hard time, also i let my buddy take it out the other day he said he put oil in so i checked it today after about an hour of riding i was curious when i took the stick out to check the oil started poring out the top so i asked my buddy how much he put in he said he filled it to the top at least he put it in the right place but any way i drained it to where it should be but could that have something to do with my problem? i also tried adjusting the clutch cable up at the handle but didn't help at all. any one know where i should start or what i may need
thanks

 

are you thinking the clutch is slipping?

 

bet clutch is slipping be wise to replace it
the oil level on those z400 can be tricky it can show low at oil tank you fill it next time you chk its overflowing its because sometimes oil stays in motor and does not go back to tank what I do is if oil level is showing half a inch on dip stick I leave it alone as long as it not blowing blue smoke out tailpipe you will be fine

 

What kind of oil did he put in ? with a wet clutch you have to use oil with no "friction modifyers". It will make the clutch plates slip. Seth 03