Spitting And Sputtering

[budhoot]

ok you guys i have a 2001 YZ125 that i bought used like a month and a half ago. Ok. When i am running it at about half throttle in like 1st 2nd and 3rd im unsure about 4th and 5th but my bike is sputtering like crazy. I rode for about 2 hours the other day and before i put it up it dident do it. but what is this a sign of?

 

[sparkysakitas]

i would look at jetting first and check plug and do a compression test to make sure its not time for a top end
check air filter make sure its clean and oiled
i know there is other stuff but thats about all i can think of

 

[budhoot]

alright thanks

 

[j32]

check the plug,and the cap,and if you plug has the screw on top make sure it is tight!!! or it will sputter -as if it was rich
also check the reeds